Tetrahydroquinoline derivatives useful for neurodegenerative disorders

Abstract: A class of 1,2,3,4-tetrahydroquinolines possessing at least one substituent, or a spirocyclic moiety, at the 4-position, and an acidic group or a group convertible thereto in vivo at the 2-position, are specific antagonists of N-methyl-D-aspartate (NMDA) receptors and are therefore useful in the treatment and/or prevention of neurodegenerative disorders..

Description: This invention relates to a class of 4-substituted 1,2,3,4-tetrahydroquinolines which are selective non-competitive antagonists of N-methyl-D-aspartate (NMDA) receptors and are therefore useful in the treatment and/or prevention of neurodegenerative disorders arising as a consequence of such pathological conditions as stroke, hypoglycaemia, cerebral palsy, transient cerebral ischaemic attack, cerebral ischaemia during cardiac pulmonary surgery or cardiac arrest, perinatal asphyxia, epilepsy, Huntington's chorea, Alzheimer's disease, Olivo-ponto-cerebellar atrophy, anoxia such as from drowning, spinal cord and head injury and poisoning by exogenous NMDA receptor agonists and neurotoxins. Various N-acyl-substituted derivatives of 1,2,3,4-tetrahydroquinoline-2-carboxylic acid, optionally substituted on the benzo moiety of the tetrahydroquinoline structure, are known to have angiotensin converting enzyme (ACE) inhibitory activity and are thus effective antihypertensive agents. Such compounds are described in, for example, DE-A-2937779, US-4273927, US-4374246, US-4390700, US-4401818, US-4461896, EP-A-0029488, J. Med. Chem ., 1983, 26 , 1267 and J. Med. Chem ., 1985, 28 , 1606. The parent compound in this series, 1,2,3,4-tetrahydroquinoline-2-carboxylic acid, is known from Chem. Ber ., 1928, 61 , 2377. None of the compounds specifically disclosed in any of the abovementioned documents, however, possesses a substituent in the 4-position of the tetrahydroquinoline moiety. Moreover, there is no suggestion in any of these documents that the compounds described therein may be useful in the treatment and/or prevention of neurodegenerative disorders. The compounds 4-oxo-1,2,3,4-tetrahydroquinoline-2-carboxylic acid and its methyl ester, and 8-hydroxy-4-oxo-1,2,3,4-tetrahydroquinoline-2-carboxylic acid, are described in J. Am. Chem. Soc ., 1967, 89 , 1017. However, no therapeutic utility is disclosed therein for these compounds. The compound 2-aminocarbonyl-4-methoxycarbonyl-1,2,3,4-tetrahydroquinoline, and its preparation from methyl 2-carbamoylcinchonate, are described in Chem. Abstr., 1969, 70 , 20044r. No pharmaceutical utility is, however, ascribed therein to this compound. The preparation of 1,2,3,4-tetrahydroquinoline-2,4-dicarboxylic acid and its diethyl ester, by zinc/formic acid reduction of the corresponding quinolinedicarboxylic acid and subsequent esterification, is described in Collect. Czech. Chem. Commun ., 1978, 43 , 1413. Again, however, no therapeutic utility for these compounds is disclosed. We have now found that a class of 1,2,3,4-tetrahydroquinolines, substituted at the 4-position of the tetrahydroquinoline ring system, are potent and selective non-competitive NMDA antagonists. They therefore have useful neuroprotective activity. The compounds act by selectively inhibiting the glycine modulation of NMDA receptors. EP-A-0203891 and US-4746653 describe inter alia certain phosphonic acid derivatives of 1,2,3,4-tetrahydroquinoline-2-carboxylic acid. The compounds described in EP-A-0203891 and US-4746653 are stated to be competitive antagonists of the NMDA-sensitive amino acid receptor. Hence, the mechanism of action of the compounds described in EP-A-0203891 and US-4746653 differs from that of the compounds according to the present invention in that the former compounds are competitive inhibitors of glutamate binding at the neurotransmitter recognition site whereas, as mentioned above, the latter compounds are non-competitive NMDA antagonists, acting as inhibitors at the glycine modulatory site on the NMDA receptor. EP-A-0303387 describes a class of substituted kynurenic acid derivatives which were found to act as NMDA antagonists by selectively inhibiting the glycine modulation of NMDA receptors. These compounds are therefore stated therein to be useful in the treatment of neurodegenerative disorders. The kynurenic acid compounds described in EP-A-0303387 possess the 4-oxo-1,4-dihydroquinoline substitution pattern; they are not 1,2,3,4-tetrahydroquinolines. The present invention provides a compound of formula IIC or a salt thereof: wherein R 1 represents a carboxy group or a group which is convertible thereto in vivo ; R 2 represents hydrogen; R 5 , R 6 , R 7 and R 8 independently represent hydrogen, halogen, cyano, trifluoromethyl, nitro, amino, carboxy, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 alkylthio or C 1-6 alkoxycarbonyl; and R a and R b independently represent hydrogen; or C 1-6 alkyl, C 2-6 alkenyl, C 3-7 cycloalkyl, C 3-7 cycloalkyl(C 1-6 )alkyl, aryl selected from phenyl, naphthyl and fluorenyl, aryl(C 1-6 )alkyl, C 3-7 heterocycloalkyl, C 3-7 heterocycloalkyl(C 1-6 )alkyl, heteroaryl selected from pyridyl, quinolyl, isoquinolyl, pyridazinyl, pyrimidinyl, pyrazinyl, pyranyl, furyl, benzofuryl, thienyl, benzthienyl, indolinyl, imidazolyl, oxadiazolyl, thiadiazolyl and tetrazolyl, or heteroaryl(C 1-6 )alkyl, any of which groups may be optionally substituted by one or more groups selected from methyl, ethyl, phenyl, chloro, aminomethyl, aminoethyl, aminopropyl, aminobutyl, methylaminomethyl, dimethylaminomethyl, aminopropynyl, aminobutynyl, hydroxy, methoxy, phenoxy, nitro, cyano, carboxy, acetyl, amino and acetylamino. For use in medicine, the salts of the compounds according to the invention will be non-toxic pharmaceutically acceptable salts. Other salts may, however, be useful in the preparation of the compounds according to the invention or of their non-toxic pharmaceutically acceptable salts. Suitable pharmaceutically acceptable salts of the compounds of this invention include alkali metal salts, e.g. sodium or potassium salts; alkaline earth metal salts, e.g. calcium or magnesium salts; and salts formed with suitable organic ligands, e.g. quaternary ammonium salts. Where appropriate, acid addition salts may, for example, be formed by mixing a solution of the compound according to the invention with a solution of a pharmaceutically acceptable non-toxic acid such as hydrochloric acid, fumaric acid, maleic acid, succinic acid, acetic acid, citric acid, tartaric acid, carbonic acid or phosphoric acid. The expression "C 1-6 alkyl" as used herein refers to straight-chained and branched alkyl groups containing from 1 to 6 carbon atoms. Typical examples include methyl and ethyl groups, and straight-chained or branched propyl and butyl groups. Particular alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and t-butyl. The expression "C 2-6 alkenyl" as used herein refers to straight-chained and branched alkenyl groups containing from 2 to 6 carbon atoms. Typical examples include vinyl and allyl groups. Suitable alkynyl groups include straight-chained and branched alkynyl groups containing from 2 to 6 carbon atoms. Typical examples include ethynyl and propargyl groups. Particular C 3-7 cycloalkyl groups are cyclopropyl and cyclohexyl. As used herein, the term "aryl" refers to groups selected from phenyl, naphthyl and fluorenyl groups. A particular aryl(C 1-6 )alkyl group is benzyl. Suitable heterocycloalkyl groups include piperidyl, piperazinyl and morpholinyl groups. As used herein, the term "heteroaryl" refers to groups selected from pyridyl, quinolyl, isoquinolyl, pyridazinyl, pyrimidinyl, pyrazinyl, pyranyl, furyl, benzofuryl, thienyl, benzthienyl, indolinyl, imidazolyl, oxadiazolyl, thiadiazolyl and tetrazolyl groups. Particular heteroaryl groups are pyridyl, furyl, thienyl, indolinyl and oxadiazolyl. The groups of formula R a and R b , where these are other than hydrogen, may in turn be optionally substituted by one or more groups selected from methyl, ethyl, phenyl, chloro, aminomethyl, aminoethyl, aminopropyl, aminobutyl, methylaminomethyl, dimethylaminomethyl, aminopropynyl, aminobutynyl, hydroxy, methoxy, phenoxy, nitro, cyano, carboxy, acetyl, amino and acetylamino. The acidic group R 1 may represent carboxy, or a group convertible thereto in vivo such as an in vivo hydrolysable ester or amido group. Such groups may be represented by the moiety -(CH 2 ) n COT wherein n is zero, and T is OR or NR p R q , where R is hydrogen, a hydrocarbon moiety such as C 1-6 alkyl, or an in vivo hydrolysable ester residue and R p and R q are independently hydrogen, a hydrocarbon moiety such as C 1-6 alkyl, or in vivo hydrolysable amido residues. Examples of suitable in vivo hydrolysable ester and amido groups for R 1 include those which break down readily in the human body to leave the parent acid or its salt. Suitable ester and amido groups R 1 of this type include those of part formulae (i)-(vi): -CO.Z.CH(R x ).O.CO.R y -CO.Z.CH 2 .Y.R f -CO.Z.R c .NR d R e -CO.Z.R c .OR h -CO.Z.R c .CO 2 R h wherein Z is O or NH; R x is hydrogen, C 1-6 alkyl or phenyl; R y is C 1-6 alkyl, C 1-6 alkoxy or phenyl, any of which may be optionally substituted by a group of formula -NR d R e ; or R x and R y together form a 1,2-phenylene group; R c represents C 1-6 alkylene optionally substituted by C 1-6 alkyl or by a carbonyl group; R d and R e independently represent hydrogen, C 1-6 alkyl, amino(C 1-6 )alkyl, mono- or di(C 1-6 )alkylamino(C 1-6 )alkyl, aryl or aryl(C 1-6 )alkyl, or R d and R e together with the intervening nitrogen atom represent a pyrrolidino, piperidino or morpholino group; Y represents oxygen or sulphur; R f represents C 1-6 alkyl, aryl or aryl(C 1-6 )alkyl; and R h represents hydrogen or C 1-6 alkyl. Thus, suitable in vivo hydrolysable ester and amido residues include, for example, acyloxyalkyl groups such as acetoxymethyl, pivaloyloxymethyl, α-acetoxyethyl and α-pivaloyloxyethyl groups; alkoxycarbonyloxyalkyl groups such as ethoxycarbonyloxymethyl and α-ethoxycarbonyloxyethyl; dialkylaminoalkyl especially di-loweralkylaminoalkyl groups such as dimethylaminomethyl, dimethylaminoethyl, dimethylaminopropyl, diethylaminomethyl or diethylaminoethyl; and heterocyclylalkyl groups such as pyrrolidinylethyl or morpholinoethyl. The benzo moiety of the tetrahydroquinoline ring system shown in formula IIC above and IID below may be unsubstituted, or substituted by one or more substituents selected from halogen, cyano, trifluoromethyl, nitro, hydroxy, amino, carboxy, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 alkylthio and C 1-6 alkoxycarbonyl. Suitably, R 8 represents hydrogen and R 5 , R 6 and R 7 independently represent hydrogen, halogen or C 1-6 alkyl. Preferably, R 6 and R 8 each represents hydrogen and R 5 and R 7 independently represent methyl, ethyl or halogen, in particular chloro, bromo or iodo. The compounds according to the invention have a number of asymmetric centres, and may accordingly exist both as enantiomers and as diastereoisomers. It is to be understood that all such isomers and mixtures thereof are encompassed within the scope of the present invention. Preferably, in relation to formula IIC above, R a is hydrogen and R b represents phenyl or benzyl, optionally substituted by an aminomethyl or aminoethyl group. The present invention also provides compounds of formula IID and salts thereof: wherein R 1 , R 2 , R 5 , R 6 , R 7 and R 8 are as defined above; R a and R i independently represent hydrogen, C 1-6 alkyl or aryl selected from phenyl, naphthyl and fluorenyl; R b represents C 3-7 cycloalkyl, aryl selected from phenyl, naphthyl and fluorenyl, or aryl(C 1-6 )alkyl, any of which groups may be optionally substituted by one or more groups selected from methyl, ethyl, chloro, iodo, methoxy and nitro; and X represents oxygen or sulphur. Suitably, R a and R i independently represent hydrogen, methyl, ethyl or phenyl; and R b represents cyclohexyl, phenyl, naphthyl or benzyl. Preferably, R a and R i both represent hydrogen; and X represents oxygen. Specific compounds within the scope of the present invention include: 4-benzoylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-acetylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-cyclohexylcarbonylamino-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(4-chlorophenylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-pyridylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-[2-(2-aminophenethyl)]carbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-n-propylcarbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-methoxyphenylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 4-benzylaminocarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-methoxybenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-methylbenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(α-methoxybenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-nitrobenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-nitrophenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-methoxyphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-methylphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(2-chlorophenylaminocarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-(4'-biphenylcarbonylamino)-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-isopropylcarbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(2-chlorophenylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(1-naphthylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-naphthylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-furylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-methylphenylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-phenethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-phenylethenylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-thienylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(3-chlorophenylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-phenylpropylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(9-fluorenylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-cyclohexylmethylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(2-chlorobenzylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(3-chlorobenzylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(4-chlorobenzylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-methylbenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-methoxybenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-nitrobenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(3-cyanophenylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(4-chlorophenylaminocarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-methylphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-methoxyphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-nitrophenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-iodophenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-[phenylaminocarbonyl(N-methyl)amino]-1,2,3,4-tetrahydroquinoline, 2-carboxy-5,7-dichloro-4-[(N-methyl-N-phenyl)aminocarbonylamino]-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2,3-dihydroindol-1-ylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-[2-(carboxyethyl)carbonylamino]-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[3-(aminomethyl)phenylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[3-(aminomethyl)phenylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)phenylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)phenylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(2-aminoethyl)phenylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(2-aminoethyl)phenylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-methylbenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-nitrobenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-methoxybenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(1-naphthylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-naphthylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-thienylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2,6-dichlorobenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-phenylaminothiocarbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-methoxyphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-methylphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(3-chlorophenylaminocarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-nitrophenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 4-(3-aminopropyl)carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-(2-aminoethyl)carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-(4-aminobutyl)carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-piperidylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(2-aminoethyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(2-aminoethyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-[4-(N-methylaminomethyl)benzylcarbonylamino]-1,2,3,4-tetrahydroquinoline; 5,7-dichloro-2-methoxycarbonyl-4-[4-(N-methylaminomethyl)benzylcarbonylamino]-1,2,3,4-tetrahydroquinoline; 5,7-dichloro-4-[4-(N,N-dimethylaminomethyl)benzylcarbonylamino]-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-[4-(N,N-dimethylaminomethyl)benzylcarbonylamino]-1,2,3,4-tetrahydroquinoline; 4-[4-(3-aminoprop-2-ynyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(3-aminoprop-2-ynyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(3-aminopropyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(3-aminopropyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(4-aminobut-2-ynyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(4-aminobut-2-ynyl)benzylcarbonylamino)-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(4-aminobutyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(4-aminobutyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[3-(aminomethyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[3-(aminomethyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[2-(aminomethyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[2-(aminomethyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[2-(4-(aminomethyl)phenyl)ethylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[2-(4-(aminomethyl)phenyl)ethylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-(4-aminobenzylcarbonylamino)-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(2-carboxyphenylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(4-chloro-3-nitrobenzylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-hydroxy-3-nitrobenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(diphenylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(1-phenylethyl)carbonylamino-1,2,3,4-tetrahydroquinoline; 4-(4-acetylbenzylcarbonylamino)-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-phenoxymethylcarbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-ethylbenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-hydroxybenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 4-(4-acetamidobenzylcarbonylamino)-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(1-naphthylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-cyclohexylaminocarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-[N-methyl-N-(4-methylphenyl)amino]carbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(N,N-diphenylamino)carbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-ethylphenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(N-ethyl-N-phenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-2-(t-butylcarbonyloxy)methoxycarbonyl-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-5,7-dichloro-2-(methylaminocarbonyl)methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-5,7-dichloro-2-[2-(N,N-dimethylamino)ethylaminocarbonyl]methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-5,7-dichloro-2-[2-(N,N-dimethylamino)ethoxycarbonyl]-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-5,7-dichloro-2-[3-(N,N-dimethylamino)propoxycarbonyl]-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-5,7-dichloro-2-[2-(N,N-dimethylamino)ethylaminocarbonyl]-1,2,3,4-tetrahydroquinoline; 5,7-dichloro-2-[2-(N,N-dimethylamino)ethylaminocarbonyl]-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)benzylcarbonylamino]-5,7-dichloro-2-(methylaminocarbonyl)methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)benzylcarbonylamino]-5,7-dichloro-2-hexyloxycarbonyl-1,2,3,4-tetrahydroquinoline; and salts thereof; wherein the relative orientation of the substituents at the 2- and 4-positions of the tetrahydroquinoline ring system is trans . The invention also provides pharmaceutical compositions comprising one or more compounds of this invention in association with a pharmaceutically acceptable carrier. Preferably these compositions are in unit dosage forms such as tablets, pills, capsules, powders, granules, sterile parenteral solutions or suspensions, or suppositories, for oral, parenteral or rectal administration. For preparing solid compositions such as tablets, the principal active ingredient is mixed with a pharmaceutical carrier, e.g. conventional tableting ingredients such as corn starch, lactose, sucrose, sorbitol, talc, stearic acid, magnesium stearate, dicalcium phosphate or gums, and other pharmaceutical diluents, e.g. water, to form a solid preformulation composition containing a homogeneous mixture of a compound of the present invention, or a non-toxic pharmaceutically acceptable salt thereof. When referring to these preformulation compositions as homogeneous, it is meant that the active ingredient is dispersed evenly throughout the composition so that the composition may be readily subdivided into equally effective unit dosage forms such as tablets, pills and capsules. This solid preformulation composition is then subdivided into unit dosage forms of the type described above containing from 0.1 to about 500 mg of the active ingredient of the present invention. The tablets or pills of the novel composition can be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action. For example, the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. The two components can be separated by an enteric layer which serves to resist disintegration in the stomach and permits the inner component to pass intact into the duodenum or to be delayed in release. A variety of materials can be used for such enteric layers or coatings, such materials including a number of polymeric acids and mixtures of polymeric acids with such materials as shellac, cetyl alcohol and cellulose acetate. The liquid forms in which the novel compositions of the present invention may be incorporated for administration orally or by injection include aqueous solutions, suitably flavoured syrups, aqueous or oil suspensions, and flavoured emulsions with edible oils such as cottonseed oil, sesame oil, coconut oil or peanut oil, as well as elixirs and similar pharmaceutical vehicles. Suitable dispersing or suspending agents for aqueous suspensions include synthetic and natural gums such as tragacanth, acacia, alginate, dextran, sodium carboxymethylcellulose, methylcellulose, polyvinylpyrrolidone or gelatin. In the treatment of neurodegeneration, a suitable dosage level is about 0.01 to 250 mg/kg per day, preferably about 0.05 to 100 mg/kg per day, and especially about 0.05 to 5 mg/kg per day. The compounds may be administered on a regimen of 1 to 4 times per day. The compounds according to the invention may be prepared by a process which comprises reducing a quinoline derivative of formula IV: wherein R 1 , R 2 , R 5 , R 6 , R 7 and R 8 are as defined above, and R 4 represents -NR a COR b or -NR i CXNR a R b as defined above. A suitable reducing agent for carrying out the above transformation is sodium cyanoborohydride. The reaction is conveniently carried out in the presence of a suitable solvent, for example acetic acid, at an elevated temperature, e.g. a temperature in the region of 50°C. The compounds of formula IIC may be prepared by reacting a compound of formula A-COR b with a compound of formula V: wherein the relative orientation of the R 1 and -NHR a substituents is trans ; R 1 , R 2 , R 5 , R 6 , R 7 , R 8 , R a and R b are as defined above; and A represents a leaving group. In this context, A suitably represents halogen, C 1-6 alkoxy or -OCOR b . The reaction is conveniently carried out by treating the compound of formula V with the appropriate acid chloride in the presence of triethylamine in an inert solvent, e.g. dichloromethane. Alternatively, the reaction may be effected by treating the compound of formula V with the appropriate carboxylic acid in the presence of a suitable condensing agent, e.g. 1,3-dicyclohexylcarbodiimide. Further methods for carrying out this transformation include standard amide bond-forming reactions used in peptide synthesis. The compounds of formula V above wherein R a is hydrogen may be prepared by reducing a compound of formula VI: wherein R 1 , R 2 , R 5 , R 6 , R 7 , R 8 and R a are as defined above. A suitable reducing agent for this purpose is zinc in acetic acid, and the reaction is conveniently carried out at room temperature. The compounds of formula VI above may be prepared by treating a compound of formula VII: wherein R 1 , R 2 , R 5 , R 6 , R 7 and R 8 are as defined above; with a hydroxylamine derivative of formula H 2 N.OR a wherein R a is as defined above, or a salt thereof, particularly the hydrochloride salt. The reaction is conveniently carried out in a suitable solvent, e.g. methanol, at reflux temperature, in the presence of a stoichiometric quantity of pyridine. In an alternative procedure, the compounds of formula V may be prepared directly from the compounds of formula VII by reductive amination. This process comprises treating a compound of formula VII as defined above with an amine of formula R a NH 2 , in which R a is as defined above, in the presence of a reducing agent. Suitable reducing agents include sodium borohydride, sodium cyanoborohydride, and hydrogen in the presence of a catalyst such as palladium on charcoal, or platinum oxide. The compounds of formula VII above may be prepared by a process which comprises cyclising a reactive derivative of a carboxylic acid of formula VIII: wherein R 1 , R 2 , R 5 , R 6 , R 7 and R 8 are as defined above and R 11 represents an amino-protecting group; and subsequently removing the amino-protecting group R 11 . The reactive derivatives of the carboxylic acid VIII suitably include esters, for example C 1-4 alkyl esters; acid anhydrides, for example mixed anhydrides with C 1-4 alkanoic acids; acid halides, for example acid chlorides; orthoesters; and primary, secondary and tertiary amides. Suitable examples of amino-protecting groups for the substituent R 11 include carboxylic acid groups such as acetyl, chloroacetyl, trifluoroacetyl, formyl, benzoyl, phthaloyl, phenylacetyl or pyridinecarbonyl; acid groups derived from carbonic acid such as ethoxycarbonyl, benzyloxycarbonyl, t-butoxycarbonyl, biphenylisopropoxycarbonyl, p-methylbenzyloxycarbonyl, p-nitrobenzyloxycarbonyl, p-bromobenzyloxycarbonyl, p-phenylazobenzyloxycarbonyl, p-(p'-methoxyphenylazo)benzyloxycarbonyl or t-amyloxycarbonyl; acid groups derived from sulphonic acid, e.g. p-toluenesulphonic acid; and other groups such as benzyl, trityl, o-nitrophenylsulphenyl or benzylidene. A preferred amino-protecting group is acetyl. The removal of the amino-protecting group present in the resultant compound may be effected by an appropriate procedure depending upon the nature of the protecting group. A typical procedure for the acetyl group involves heating at reflux temperature in the presence of 3N hydrochloric acid. When R 1 in the compounds according to the invention represents carboxy, it is convenient to replace the carboxylic acid VIII in the above reaction with a cyclic anhydride of formula IX: wherein R 2 , R 5 , R 6 , R 7 , R 8 and R 11 are as defined above. The reaction is suitably carried out in the presence of a Lewis acid catalyst such as aluminium chloride; and is conveniently effected at an elevated temperature, for example a temperature in the region of 160°C, suitably in the melt. In an alternative process, the compounds according to the invention may be prepared by reacting a compound of formula X, or a protected derivative thereof, with a compound of formula XI, or a protected derivative thereof: wherein R 1 , R 2 and R 4 to R 8 are as defined above; followed, where necessary, by removal of the protecting groups. The reaction is conveniently carried out at room temperature in an inert solvent, e.g. dichloromethane, in the presence of a Lewis acid catalyst such as boron trifluoride etherate. Illustrative experimental details for this reaction are described in J. Heterocycl. Chem ., 1988, 25 , 1831. As will be appreciated, any compound of formula I initially obtained may, where appropriate, subsequently be elaborated into a further compound of formula I by techniques known from the art. The intermediates of formulae IV, VIII and IX may conveniently be prepared by methods analogous to those described in the accompanying Examples. Except where explicitly stated otherwise, the above-described processes for the preparation of the compounds according to the invention are likely to give rise to mixtures of stereoisomers. At an appropriate stage, these isomers may be separated by conventional techniques such as preparative chromatography. The novel compounds may be prepared in racemic form, or individual enantiomers may be prepared either by enantiospecific synthesis or by resolution. The novel compounds may, for example, be resolved into their component enantiomers by standard techniques, such as the formation of diastereomeric pairs by salt formation with an optically active acid, such as (-)-di-p-toluoyl-d-tartaric acid and/or (+)-di-p-toluoyl-l-tartaric acid followed by fractional crystallization and regeneration of the free base. The novel compounds may also be resolved by formation of diastereomeric esters or amides, followed by chromatographic separation and removal of the chiral auxiliary. During any of the above synthetic sequences it may be necessary and/or desirable to protect sensitive or reactive groups on any of the molecules concerned. This may be achieved by means of conventional protecting groups, such as those described in Protective Groups in Organic Chemistry , ed. J.F.W. McOmie, Plenum Press, 1973; and T.W. Greene, Protective Groups in Organic Synthesis , John Wiley & Sons, 1981. The protecting groups may be removed at a convenient subsequent stage using methods known from the art. The compounds useful in this invention potently and selectively block responses to NMDA in a brain slice from rat cortex, and inhibit glycine binding to the strychnine-insensitive site present on the NMDA receptor. Cortical Slice Studies The effects of compounds of the invention on responses to NMDA were assessed using the rat cortical slice as described by Wong et al ., Proc. Natl. Acad. Sci. USA , 1986, 83 , 7104. The apparent equilibrium constant (K b ) was calculated from the righthand shift in the NMDA concentration-response curve produced by the compound under test. The compounds of the accompanying Examples were tested and each was found to possess a K b value below 100 µM. Inhibition of Glycine Binding The ability of test compounds to displace 3 H-glycine binding to the strychnine-insensitive site present on the NMDA receptor of rat forebrain membranes was determined by the method of Donald et al ., Proceedings of The British Pharmacological Society , University of Nottingham, September 1988, Abstract P122. The concentration of the compounds of each of the accompanying Examples required to displace 50% of the specific binding (IC 50 ) is below 100 µM. PREPARATIVE EXAMPLE A 2-Carboxy-5,7-dichloro-4-oxo-1,2,3,4-tetrahydroquinoline a) Methyl 2-(3,5-dichlorophenylamino)-3-methoxycarbonylpropionate 3,5-Dichloroaniline (104g) and dimethylacetylene dicarboxylate (79ml) were dissolved in dry methanol (100ml) and heated under reflux for 14h. On cooling a yellow solid crystallised out and this was collected by filtration. The mother liquors were concentrated in vacuo to leave a residue from which a second crop of product was obtained by recrystallisation from diethyl ether/60-80 petrol. The combined crops of material weighed 167.5g (after drying at 40°C under a pressure of 20mmHg for 18h). A portion of this material (105g) was dissolved in ethyl acetate (1000ml) and hydrogenated at 50 psi over 10% palladium on carbon catalyst (4g) for 40h. The catalyst was removed by filtration and the solvent evaporated under vacuum to leave a residue which was recrystallised from diethyl ether/hexane to give the title compound as a white crystalline solid (84.8g, m.p. 66-67°C). b) 3-Carboxy-2-(3,5-dichlorophenylamino)-propionic acid Methyl 2-(3,5-Dichlorophenyl)amino-3-methoxycarboxyl-propionate (131.4g) was dissolved in methanol (800ml) and sodium hydroxide (51.5g in 600ml of water) was added. The reaction mixture was stirred at room temperature for 5h then the methanol was removed under vacuum and the residual solution was acidified to pH l by the cautious addition of concentrated hydrochloric acid. The aqueous solution was extracted with ethyl acetate (2 x 600ml) and the combined organic layers were dried (MgSO 4 ), filtered and concentrated in vacuo to give the required compound as a white solid (11.6g, m.p. 217°C dec). c) 2-[N-Acetyl-N-(3,5-dichlorophenyl)amino]-3-carboxy-propionic acid 3-Carboxy-2-(3,5-dichlorophenylamino)-propionic acid (116g) was suspended in acetic anhydride (1000ml) and heated at 60-70°C under nitrogen for 6h then cooled and concentrated in vacuo . The residue which was obtained was dissolved in methanol (500ml) and sodium hydroxide solution (500ml of 2.5N) was added. The reaction mixture was stirred at room temperature for 14h then the methanol was removed by evaporation. The residual aqueous solution was washed with diethyl ether (2 x 200ml) the acidified to pH l with concentrated hydrochloric acid and extracted into ethyl acetate (2 x 500ml), dried (MgSO 4 ), filtered and concentrated under vacuum. The residue obtained was triturated with diethyl ether and collected by filtration to give the the title compound as a white solid (128.5g, m.p. 181°C dec). d) 1-Acetyl-2-carboxy-5,7-dichloro-4-oxo-1,2,3,4-tetrahydroquinoline 2-[N-Acetyl-N-(3,5-dichlorophenyl)amino]-3-carboxy-propionic acid (128g) was suspended in dichloromethane (1000ml) and acetyl chloride (300ml) was added. The reaction mixture was stirred overnight at room temperature under an inert atmosphere, filtered, then concentrated in vacuo and then dried under high vacuum to give as an off white solid the required substituted succinic anhydride (119.8g). A portion of this material (60g) and finely ground aluminium trichloride (168g) were blended together and heated at 170°C for 30 min. After this time the reaction mixture was allowed to cool and ice cold 1N hydrochloric acid was added cautiously until effervescence ceased. The aqueous layer was decanted and the residual solid retained and combined with the product from a second reaction carried out on the remaining anhydride (50.8g). The solid was triturated with absolute ethanol and the title compound was collected by filtration (20.2g, m.p. 212-213°C). e) 2-Carboxy-5,7-dichloro-4-oxo-1,2,3,4-tetrahydroquinoline 1-Acetyl-2-carboxy-5,7-dichloro-4-oxo-1,2,3,4-tetrahydroquinoline (21.17g) was suspended in 3N hydrochloric acid (500ml) and heated at reflux overnight. After cooling, the aqueous solution was extracted with ethyl acetate (3 x 300ml) and the combined organic layers were washed with brine (1 x 300ml), dried (MgSO 4 ), filtered and evaporated in vacuo to give the title compound as a yellow solid (17.45g, m.p. 218-219°C). PREPARATIVE EXAMPLE B Trans-4-tertiary-butyloxycarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline a) 5,7-Dichloro-4-hydroxyimino-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline To a solution of 2-carboxy-5,7-dichloro-4-oxo-1,2,3,4-tetrahydroquinoline (Preparative Example A) (14.85g, 57.1mmol) in methanol (300ml) was added hydroxylamine hydrochloride (4.17g, 60.0mmol) followed by dry pyridine (4.85ml, 60.0mmol) and the resulting mixture was heated at reflux under an atmosphere of nitrogen for 2 hours. The mixture was then cooled, and a solution of methanol saturated with hydrogen chloride (50ml) was added and the reaction was stirred at room temperature under an atmosphere of nitrogen for 17 hours. The solvent was removed in vacuo and the residue was partitioned between water (300ml) and diethyl ether (300ml). The aqueous phase was further extracted with diethyl ether (2 x 300ml) and the combined organic layers were washed with 0.5M aqueous citric acid solution (1 x 200ml), saturated hydrogen sodium bicarbonate solution (2 x 200ml), brine (1 x 200ml), then dried (MgSO 4 ) and the solvent was removed under vacuum to give the title compound (15.1g) as a brown solid (m.p. 216-217°C). b) Cis and trans-4-tertiary-butyloxcarbonylamino-5,7- dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline To a suspension of 5,7-dichloro-4-hydroxyimino-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline (8.0g, 27.7mmol) in glacial acetic acid (240ml) was added zinc dust (12.0g, 18mmol) and the resulting mixture was heated at 60-65°C, under an atmosphere of nitrogen, with stirring for 4 hours. The reaction mixture was allowed to cool, then filtered and the filtrate was evaporated in vacuo . The residue was redissolved in ethyl acetate (400ml), washed with saturated sodium bicarbonate solution (2 x 200ml) and saturated brine solution (1 x 200ml) then dried (MgSO 4 ), filtered and concentrated under vacuum to give a brown foam (6.60g). To a solution of this foam in dichloromethane (350ml) was added di- tertiary -butyl-dicarbonate (12.0g, 55mmol) and the mixture was stirred at room temperature for 65 hours under an atmosphere of nitrogen. To the reaction mixture was added N,N-dimethylethylenediamine (6.6ml, 60mmol) and stirring was continued for a further 2 hours. The reaction mixture was washed successively with 0.5M citric acid solution (2 x 200ml) and brine (1 x 200ml), dried (MgSO 4 ), filtered and the solvent was removed under vacuum to give an oily solid (5.8g). This was purified by flash chromatography using 20% ethyl acetate in petroleum ether (bp 60-80°C) as eluent to give a mixture of cis and trans isomers. Trituration of this mixture with diethyl ether gave a solid which was collected by filtration and was recrystallised from hot ethyl acetate/petroleum ether (bp 60-80°C) to give, as colourless needles, the less polar Trans-4-tertiarybutyloxycarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline (1.33g, m.p. 210-211°C). c) Trans-4-tertiary-butyloxycarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline To a solution of trans -4-tertiary-butyloxycarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline (0.153g, 0.408mmol) in tetrahydrofuran (10ml) was added aqueous lithium hydroxide (0.45ml of a 1.0M solution, 0.45mmol) followed by distilled water (3ml) and the resulting mixture was stirred at room temperature for 4 hours. The mixture was then evaporated to dryness under vacuum and the residue was redissolved in water (40ml). The solution was adjusted to pH 1 with dilute hydrochloric acid and the mixture was extracted with ethyl acetate (2 x 30ml). The combined organic extracts were washed with brine then dried (MgSO 4 ), and concentrated in vacuo to give an oil from which two crops of crude product were obtained by recrystallisation from diethyl ether/petroleum ether (bp 60-80°C). The combined material was dissolved in methanol and evaporated under vacuum to give an oil which was recrystallised from diethyl ether to give the pure title compound as colourless crystals (0.071g, m.p. 193-195°C). PREPARATIVE EXAMPLE C Trans-4-amino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride To a suspension of trans -4-tertiary-butyloxy-carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline (80mg, 0.222mmol) in ethyl acetate (3ml) was added hydrogen chloride in ethyl acetate (3ml of an approximately 5M solution) and the resulting mixture was stirred at room temperature for 5 hours. The solvent was removed under vacuum and the residue was triturated with ethyl acetate. The solid obtained was collected by filtration then washed with ethyl acetate and dried to give as a colourless solid, the title compound (0.054g, m.p. 184-188°C). EXAMPLE 1 Trans-2-carboxy-5,7-dichloro-4-benzoylamino-1,2,3,4-tetrahydroquinoline a) Trans-4-amino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride To a suspension of trans -4-tertiary-butyloxy-carbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline (1.2g) in ethyl acetate (25ml) was added a solution of hydrogen chloride in ethyl acetate (25M of an approx 5M solution) and the resulting mixture was stirred at room temperature for 3 hours after which time the solvent was removed in vacuo . The residue was triturated with ethyl acetate and the solid was collected to give the title compound as a colourless solid (0.96g, m.p. 192-194°C [sublimes]). b) Trans-5,7-dichloro-2-methoxycarbonyl-4-benzoylamino-1,2,3,4-tetrahydroquinoline To a suspension of trans -4-amino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride (0.2g, 0.642mmol) in anhydrous dichloromethane (15ml) was added dry triethylamine (220ml, 1.4mmol) and the resulting mixture was stirred at room temperature under an atmosphere of nitrogen until dissolution was complete. To this solution was added benzoyl chloride (82ml, 0.706mmol) and stirring was continued for 17 hours. The solvent was removed in vacuo and the residue was partitioned between ethyl acetate (100ml) and dilute citric acid (150ml). The organic layer was washed successively with saturated sodium bicarbonate solution (2 x 50ml) and brine (50ml) then dried (MgSO 4 ) and evaporated to give the crude product (0.26g) which was recrystallised from ethyl acetate/petroleum ether (bp 60-80°C) to give the pure title compound as colourless crystals (0.201g, m.p. 258-259°C). c) Trans-2-carboxy-5,7-dichloro-4-benzoylamino-1,2,3,4-tetrahydroquinoline To a solution of trans -5,7-dichloro-2-methoxy-carbonyl-4-benzoylamino-1,2,3,4-tetrahydroquinoline (0. 189g, 0.499mmol) in tetrahydrofuran (10ml) was added distilled water (5ml) followed by aqueous lithium hydroxide (1.10ml of a 0.50M solution, 0.549mmol) and the resulting mixture was stirred at room temperature for 3 hours. The organic solvent was removed under vacuum and to the aqueous residue was added saturated sodium bicarbonate solution (20ml) and deionised water (50ml). The mixture was washed with ethyl acetate (2 x 50ml), then acidified to pH 1 with dilute hydrochloric acid and extracted with ethyl acetate (2 x 50ml). The combined organic extracts were washed with brine (50ml) then dried (Na 2 SO 4 ) and evaporated to give the crude product (0.16g) which was triturated with diethyl ether to give two crops of the pure title compound as a colourless crystalline solid (0.11g, m.p. 233-236°C). EXAMPLE 2 Trans-2-carboxy-5,7-dichloro-4-acetylamino-1,2,3,4-tetrahydroquinoline a) Trans-5,7-dichloro-2-methoxycarbonyl-4-acetyl-amino-1,2,3,4-tetrahydroquinoline To a suspension of trans -4-amino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride (0.15g, 0.481mmol) in anhydrous dichloromethane (15ml) was added dry triethylamine (0.141ml, 1.01mmol) and the resulting mixture was stirred at room temperature under an atmosphere of nitrogen until dissolution was complete. To this solution was added acetyl chloride (38ml, 0.529mmol) and the reaction mixture was stirred under an atmosphere of nitrogen for a further 5 hours at room temperature. The precipitate was collected by filtration and was washed with dichloromethane to give the title compound as a colourless crystalline solid (0.133g, m.p. 280-282°C) (dec.). b) Trans-2-Carboxy-5,7-dichloro-4-acetylamino-1,2,3,4-tetrahydroquinoline To a suspension of trans -5,7-dichloro-2-methoxy-carbonyl-4-acetylamino-1,2,3,4-tetrahydroquinoline (0.12g, 0.379mmol) in methanol (5ml) was added aqueous lithium hydroxide (0.42ml of a 1.0M solution, 0.42mmol) and the resulting mixture was stirred at room temperature for 7 hours. To this mixture was added additional aqueous lithium hydroxide (0.20ml of a 1.0M solution, 0.20mmol) and the mixture was stirred for a further 16 hours. The solution was evaporated to dryness in vacuo and the residue obtained was redissolved in water (50ml). The solution was acidified to pH l with dilute hydrochloric acid and extracted with ethyl acetate (2 x 30ml). The combined extracts were washed with brine (30ml), dried (Na 2 SO 4 ) and evaporated to give the pure title compound as colourless crystals (0.108g, 223-225°C). EXAMPLE 3 Trans-2-carboxy-4-cyclohexylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline a) Trans-4-cyclohexylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline This material was prepared by the same method as described in Example 1b using cyclohexane carboxylic acid to give the title compound (m.p. 280-282°C dec). b) Trans-2-carboxy-4-cyclohexylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline This material was prepared using the same method as described in Example 1c to give the title compound (Et 2 O, m.p. 190-195°C). EXAMPLE 4 Trans-2-carboxy-5,7-dichloro-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline a) Trans-5,7-dichloro-2-methoxycarbonyl-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline This material was prepared by the same method as described in Example 1b using phenylacetyl chloride to give the title compound as colourless crystals (m.p. 226-228°C). b) Trans-2-carboxy-5,7-dichloro-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline This material was prepared by the same method as described in Example 1c to give the title compound as colourless crystals (m.p. 186-188°C dec). EXAMPLE 5 Trans-2-carboxy-5,7-dichloro-4-(4-pyridyl)carbonyl amino-1,2,3,4-tetrahydroquinoline a) Trans-5,7-dichloro-2-methoxycarbonyl-4(4-pyridyl)carbonylamino-1,2,3,4-tetrahydroquinoline To a suspension of trans -4-amino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride (example 1a) (0.200g, 0.642 mmol) and isonicotinoyl chloride hydrochloride (0. 124g, 0.706mmol) in anhydrous dichloromethane (20ml) under an atmosphere of nitrogen was added dry triethylamine (0.307ml, 2.2mmol) and the resulting mixture was stirred at room temperature for 1h. The mixture was then evaporated to dryness in vacuo and the residue was partitioned between water (100ml) and ethyl acetate (250ml). The organic layer was separated, washed successively with water (3 x 100ml), saturated sodium bicarbonate solution (1 x 100ml), brine (1 x 100ml), dried (MgSO 4 ) and evaporated. The resulting solid was triturated with ethyl acetate and collected by filtration to give the title compound as colourless crystals (0.200g) mp 200°C (dec). b) Trans-2-carboxy-5,7-dichloro-4(4-pydridyl)carbonylamino-1,2,3,4-tetrahydroquinoline To a suspension of trans -5,7-dichloro-2-methoxycarbonyl- 4(4-pyridyl)-carbonylamino-1,2,3,4-tetrahydroquinoline (0.18g, 0.47mmol) in a mixture of tetrahydrofuran (15ml) and water (5ml) was added aqueous lithium hydroxide (1.04ml of a 0.50M solution, 0.521mmol) and the resulting mixture was stirred at room temperature for 3h. The organic solvent was removed in vacuo then the aqueous residue was diluted with dilute sodium bicarbonate solution (100ml) and washed with ethyl acetate (2 x 75ml). The aqueous layer was then acidified to pH 6 with dilute hydrochloric acid and extracted with ethyl acetate (4 x 75ml). The combined extracts were washed with brine (1 x 100ml), dried (Na 2 SO 4 ) and evaporated to give the title compound as colourless crystals (0.116g), m.p. 270-275°C [dec]. EXAMPLE 6 Trans-2-carboxy-5,7-dichloro-4-n-propylcarbonylamino-1,2,3,4-tetrahydroquinoline a) Trans-5,7-dichloro-2-methoxycarbonyl-4-n-propylcarbonylamino-1,2,3,4-tetrahydroquinoline To a suspension of trans -4-amino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride (example 1a) (0.200g, 0.642mmol) in anhydrous dichloromethane (15ml) under an atmosphere of nitrogen was added dry triethylamine (0. 197ml, 1.41mmol) and the mixture was stirred until dissolution was complete. To this solution was then added butyryl chloride (0.073ml, 0.706mmol) and the reaction was stirred at room temperature for 4h. The mixture was then evaporated to dryness in vacuo and the residue was partitioned between ethyl acetate (50ml) and 0.5M aqueous citric acid (30ml). The organic layer was separated, washed successively with saturated sodium bicarbonate solution (1 x 30ml) and brine (1 x 30ml), then dried (MgSO 4 ) and evaporated to give a solid which was triturated with diethyl ether. The solid was collected by filtration to give the pure title compound as colourless crystals (0. 187g), m.p. 205-206°C. b) Trans-2-carboxy-5,7-dichloro-4-n-pronylcarbonylamino-1,2,3,4-tetrahydroquinoline To a solution of trans -5,7-dichloro-2-methoxycarbonyl-4-n-propylcarbonyl-amino-1,2,3,4-tetrahydroquinoline (0.70g, 0.493mmol) in a mixture of tetrahydrofuran (15ml) and water (5ml) was added aqueous lithium hydroxide (1.1ml of a 0.50M solution, 0.55mmol) and the resulting mixture was stirred at room temperature for 20h. The organic solvent was then removed under vacuum and the aqueous residue was diluted with dilute sodium bicarbonate solution (50ml) then washed with ethyl acetate (1 x 30ml). The aqueous phase was separated, acidified with dilute hydrochloric acid and extracted with ethylacetate (2 x 50ml). The combined extracts were washed with brine (1 x 50ml), dried (MgSO 4 ) and evaporated to give a solid which was triturated with diethyl ether to give the title compound as colourless crystals (0.123g) m.p. 174-176°C (dec). EXAMPLE 7 Trans-2-carboxy-5,7-dichloro-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline a) Trans-5,7-dichloro-2-methoxycarbonyl-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline To a suspension of 4-amino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride (example 1a) (3.0g, 9.63mmol) in anhydrous tetrahydrofuran (300ml) under an atmosphere of nitrogen was added dry triethylamine (2.95ml, 21.2mmol) and the resulting mixture was stirred at room temperature for 0.5h. To this suspension was added phenylacetic acid (1.44g, 10.6mmol), 1-hydroxybenzotriazole (1.43g, 10.6mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (2.03g, 10.6mmol) and stirring was continued for 65h. The reaction mixture was concentrated in vacuo and the residue obtained was partitioned between ethyl acetate (1000ml) and 1M aqueous citric acid (300ml). The organic layer was collected, washed successively with 1M aqueous citric acid (1 x 300ml), saturated sodium bicarbonate solution (2 x 300ml) and brine (200ml) then dried (MgSO 4 ) and evaporated. The resulting crude product was recrystallised from methanol to give the title compound as colourless needles (2 crops, 3.26g) identical in physical properties to the material obtained in example 4 step a. b) Trans-2-carboxy-5,7-dichloro-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline To a suspension of trans -5,7-dichloro-2-methoxy-carbonyl-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline (3.11g, 7.89mmol) in a mixture of tetrahydrofuran (100ml) and water (50ml) was added aqueous lithium hydroxide (17.4ml of a 0.5M solution, 8.70mmol) and the resulting mixture was stirred at room temperture for 3h. The organic solvent was removed in vacuo and the aqueous residue was acidified with concentrated hydrochloric acid and extracted with ethyl acetate (2 x 100ml). The combined extracts were washed with saturated brine (1 x 100ml), dried (MgSO 4 ) and evaporated to give the crude product which was recrystallised from ethyl acetate/petroleum ether 60-80 to give the title compound as colourless crystals (2 crops, 2.65g) identical in physical properties to example 4 step b. EXAMPLE 8 Trans-2-carboxy-5,7-dichloro-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline a) Trans-5,7-dichloro-2-methoxycarbonyl-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline To a suspension of trans -4-amino-5,7-dichloro-2-methoxy-carbonyl-1,2,3,4-tetrahydroquinoline hydrochloride (0.200g, 0.642mmol) in anhydrous dichloromethane (20ml) under an atmosphere of nitrogen was added dry triethylamine (0.098ml, 0.706mmol) and the mixture was stirred until dissolution was complete. To this solution was then added phenyl isocyanate (0.077ml, 0.706mmol) and the resulting mixture was stirred at room temperature for 2h. The solvent was removed under vacuum and the residue was partitioned between ethyl acetate (150ml) and 1M aqueous citric acid (75ml). The organic layer was successively washed with 1M aqueous citric acid (1 x 75ml), saturated sodium bicarbonate solution (2 x 75ml) and saturated brine ( 1 x 75ml), then dried (MgSO 4 ) and evaporated. The crude product was recrystallised from methanol to give the title compound as colourless crystals (0.185g), m.p. 228-229°C (dec). b) Trans-2-carboxy-5,7-dichloro-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline. To a suspension of trans -5,7-dichloro-2-methoxycarbonyl-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline (0.185g, 0.47mmol) in a mixture of tetrahydrofuran (10ml) and water (5ml) was added aqueous lithium hydroxide (1.04ml of a 0.5M solution, 0.52 mmol) and the resulting mixture was stirred at room temperature for 2h. The reaction mixture was concentrated in vacuo and the aqueous residue was dissolved in dilute sodium bicarbonate solution (100ml) then washed with diethyl ether (100ml). The aqueous phase was separated, acidified with concentrated hydrochloric acid and extracted with ethyl acetate (2 x 100ml). The combined extracts were washed with brine (100ml), dried (MgSO 4 ) and evaporated to give the crude product which was redissolved in methanol and evaporated to give an oil which was crystallised with diethyl ether. The title compound was collected by filtration to give colourless crystals (0.110g), m.p. 148-150°C (starts to decompose above 120°C). EXAMPLE 9 Trans-2-carboxy-4(4-chlorophenyl)carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline This compound was prepared by the same method given for example 6 using 4-chlorobenzoyl chloride in place of butyryl chloride to give the title compound as colourless crystals m.p. 228-229°C (dec). EXAMPLE 10 Trans-2-carboxy-5,7-dichloro-4(4-methoxyphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the same method given for example 6 using para -anisoyl chloride in place of butyryl chloride to give the title compound as colourless crystals, m.p. 209-210°C (dec). EXAMPLE 11 Trans-2-carboxy-5,7-dichloro-4-phenylmethylaminocarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared using the same method given for example 8 using benzyl isocyanate in place of phenyl isocyanate to give the title compound as colourless crystals, m.p. 163-164°C (dec). EXAMPLE 12 Trans-2-carboxy-5,7-dichloro-4(2-methoxyphenyl) methylcarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared using the same method given for example 7 using 2-methoxyphenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 222-223°C (dec). EXAMPLE 13 Trans-2-carboxy-5,7-dichloro-4(2-methylphenyl)methylcarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared using the same method given for example 7 using ortho -tolylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 214-215°C (dec). EXAMPLE 14 Trans-2-carboxy-5,7-dichloro-4-phenyl(methoxy) methylcarbonylamino-1,2,3,4-tetrahydroquinoline (Isomer A) Step a): Trans-5,7-dichloro-2 methoxycarbonyl-4-phenyl(methoxy) methylcarbonylamino-1,2,3,4-tetrahydroquinoline (Isomers A and B) To a suspension of trans -4-amino-5,7-dichloro-2-methoxy-carbonyl-1,2,3,4-tetrahydroquinoline hydrochloride (example 1a) (0.400g, 1.28mmol) in anhydrous THF (50ml) was added dry triethylamine (0.393ml, 2.82mmol) and the resulting mixture was stirred at room temperature under an atmosphere of nitrogen for 0.25h. To this suspension was then added (+)-α-methoxyphenylacetic acid (0.234g, 1.41mmol), 1-hydroxybenzotriazole (0.191g, 1.41mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.270g, 1.41mmol) and stirring was continued for 4h. The solvent was then removed under vacuum and the residue was partitioned between ethyl acetate (100ml) and 1M aqueous citric acid (100ml). The organic layer was separated and washed successively with 1M aqueous citric acid (1 x 75ml), saturated sodium bicarbonate solution (2 x 75ml), saturated brine (1 x 75ml) then dried (MgSO 4 ) and evaporated to give a solid. The two diastereoisomers were separated by flash chromatography using 30-40% ethyl acetate in petroleum ether (bp 60-80°) as eluent to give, after recrystallisation from hot ethyl acetate-petroleum (ether bp 60-80°), the less polar isomer A (0.234g, m.p. 182-184°C) and the more polar isomer B (0.162g, m.p. 228-229°C). Step b: Trans-2-carboxy-5,7-dichloro-4-phenyl(methoxy) methylcarbonylamino-1,2,3,4-tetrahydroquinoline (Isomer A) To a solution of trans -5,7-dichloro-2-methoxycarbonyl-4-phenyl(methoxy)methylcarbonylamino-1,2,3,4-tetrahydroquinoline (Isomer A, 0.180g, 0.426mmol) in a mixture of tetrahydrofuran (10ml) and water (5ml) was added aqueous lithium hydroxide (0.904ml of a 0.50M solution, 0.47mmol), and the resulting mixture was stirred at room temperature for 3h. The solvent was then removed under vacuum and the residue was diluted with sodium bicarbonate solution (50ml) and washed with diethyl ether (1 x 30ml). The aqueous layer was separated, acidified with concentrated hydrochloric acid and extracted with ethyl acetate (2 x 40ml). The combined extracts were washed with saturated brine (1 x 40ml), dried (MgSO 4 ) and evaporated to give a solid which was recrystallised from hot ethyl acetate/petroleum ether (bp 60-80°) to give the title compound as colourless crystals (0.102g), m.p. 232-233°C. EXAMPLE 15 Trans-2-carboxy-5,7-dichloro-4-phenyl(methoxy) methylcarbonylamino-1,2,3,4-tetrahydroquinoline (Isomer B) To a solution of trans -5,7-dichloro-2-methoxycarbonyl-4-phenyl(methoxy)methylcarbonylamino-1,2,3,4-tetrahydroquinoline (Isomer B) (0.140g, 0.331mmol) (Example 14a) in a mixture of tetrahydrofuran (10ml) and water (5ml) was added aqueous lithium hydroxide (0.73ml of a 0.5M solution, 0.364mmol) and the resulting mixture was stirred at room temperature for 2h. The organic solvent was removed under vacuum and the residue was diluted with sodium bicarbonate solution (50ml) then washed with diethyl ether (1 x 30ml). The aqueous layer was separated, acidified with concentrated hydrochloric acid and extracted with ethyl acetate (2 x 40ml). The combined extracts were washed with saturated brine (1 x 40ml), dried (MgSO 4 ) and evaporated to give the crude product which was recrystallised from hot ethyl acetate/petroleum ether (bp 60-80°) to give the title compound as colourless crystals (0.070g), m.p. 238-239°C. EXAMPLE 16 Trans-2-carboxy-5,7-dichloro-4-(2-nitrophenyl)methyl carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared using the same method given for example 7 using 2-nitrophenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 220-221°C (dec). EXAMPLE 17 Trans-2-carboxy-5,7-dlchloro-4-(2-nitrophenyl)amino carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared using the same method given for example 8 using 2-nitrophenyl isocyanate in place of phenyl isocyanate to give the title compound as yellow crystals, mp 214-215°C (dec). EXAMPLE 18 Trans-2-carboxy-5,7-dichloro-4-(2-methoxyphenyl)amino carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared using the same method given for example 8 using 2-methoxyphenyl isocyanate in place of phenylisocyanate to give the title compound as colourless crystals, m.p. 198-199°C (dec). EXAMPLE 19 Trans-2-carboxy-5,7-dichloro-4-(2-methylphenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared using the method given for example 8 using ortho -tolyl isocyanate in place of phenyl isocyanate to give the title compound as colourless crystals, m.p. 196-197°C (dec). EXAMPLE 20 Trans-2-carboxy-5,7-dichloro-4(2-chlorophenyl)amino carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared using the method given for example 8 using ortho -chlorophenyl isocyanate in place of phenyl isocyanate to give the title compound as colourless crystals, m.p. 203-204°C (dec). Examples 21 to 34 hereinbelow were prepared by the method of Example 6 utilising the appropriate acid chloride in place of butynyl chloride. EXAMPLE 21 Trans-2-carboxy-5,7-dichloro-4(4-phenyl)phenylcarbonyl amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 267°C. EXAMPLE 22 Trans-2-carboxy-5,7-dichloro-4-isopropylcarbonylamino- 1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 197-198°C. EXAMPLE 23 Trans-2-carboxy-5,7-dichloro-4-(2-chlorophenyl)carbonylamino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 141-143°C. EXAMPLE 24 Trans-2-carboxy-5,7-dichloro-4-(1-naphthalenyl)carbonyl amino1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 263-264°C. EXAMPLE 25 Trans-2-carboxy-5,7-dichloro-4-(2-naphthalenyl)carbonylamino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 193-194°C. EXAMPLE 26 Trans-2-carboxy-5,7-dichloro-4-(2-furanylcarbonyl)amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 219-220°C. EXAMPLE 27 Trans-2-carboxy-5,7-dichloro-4-(2-methylphenyl)carbonyl amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 153-156°C. EXAMPLE 28 Trans-2-carboxy-5,7-dichloro-4-(phenethylcarbonyl)amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 188°C. EXAMPLE 29 Trans-2-carboxy-5,7-dichloro-4-(phenethenyl carbonyl)amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 214-216°C. EXAMPLE 30 Trans-2-carboxy-5,7-dichloro-4-(2-thiophenylmethyl carbonyl)amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 166-169°C. EXAMPLE 31 Trans-2-carboxy-5,7-dichloro-4-(3-chlorophenyl)carbonyl amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 262-263°C. EXAMPLE 32 Trans-2-carboxy-5,7-dichloro-4-(3-phenylpropyl) carbonylamino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 189-191°C. EXAMPLE 33 Trans-2-carboxy-5,7-dichloro-4-(9-fluorenyl)carbonyl amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 266-268°C. EXAMPLE 34 Trans-2-carboxy-5,7-dichloro-4-(cyclohexylmethylcarbonyl) amino-1,2,3,4-tetrahydroquinoline Colourless crystals m.p. 197-200°C. Examples 35 to 41 hereinbelow were prepared by the method of Example 7 utilising the appropriate carboxylic acid in place of phenylacetic acid. EXAMPLE 35 Trans-2-carboxy-5,7-dichloro-4-(2-chlorophenyl)methylcarbonylamino- 1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 244-245°C. EXAMPLE 36 Trans-2-carboxy-5,7-dichloro-4-(3-chlorophenylmethylcarbonyl)amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 193-194°C. EXAMPLE 37 Trans-2-carboxy-5,7-dichloro-4-(4-chlorophenylmethylcarbonyl)amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 244-245°C. EXAMPLE 38 Trans-2-carboxy-5,7-dichloro-4-(4-methylphenylmethylcarbonyl)amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 229-230°C. EXAMPLE 39 Trans-2-carboxy-5,7-dichloro-4-(4-methoxyphenylmethyl)carbonylamino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 245-247°C. EXAMPLE 40 Trans-2-carboxy-5,7-dichloro-4-(4-nitrophenylmethylcarbonyl)amino-1,2,3,4-tetrahydroquinoline Yellow crystals m.p. 246-248°C. EXAMPLE 41 Trans-2-carboxy-5,7-dichloro-4-(3-cyanophenylcarbonyl)amino-1,2,3,4-tetrahydroquinoline Colourless crystals, m.p. 229-231°C. EXAMPLE 42 Trans-2-carboxy-5,7-dichloro-4-(4-chlorophenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 8 using 4-chlorophenyl isocyanate in place of phenyl isocyanate to give the title compound as colourless crystals, m.p. 199-200°C. EXAMPLE 43 Trans-2-carboxy-5,7-dichloro-4-(4-methylphenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 8 using 4-methylphenyl isocyanate in place of phenyl isocyanate to give the title compound as colourless crystals, m.p. 197-198°C. EXAMPLE 44 Trans-2-carboxy-5,7-dichloro-4-(4-methoxyphenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for example 8 using 4-methoxyphenyl isocyanate in the place of phenyl isocyanate to give the title compound as colourless crystals, m.p. 189-190°C. EXAMPLE 45 Trans-2-carboxy-5,7-dichloro-4-(4-nitrophenyl)amino carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 8 using 4-nitrophenyl isocyanate in place of phenyl isocyanate to give the title compound as yellow crystals, m.p. 185-186°C. EXAMPLE 46 Trans-2-carboxy-5,7-dichloro-4-(4-iodophenyl)amino carbonylamino-1,2,3,4-tetrahydroquinoline Step a: 1-Phenyl-3-(4-Iodophenyl)carbamate To a solution of 4-iodoaniline (1.94g, 8.85mmol) in anhydrous dichloromethane (40ml) was added phenylchloroformate (1.11ml, 8.85mmol) and triethylamine (1.42ml, 10.28mmol). The mixture was stirred under an atmosphere of nitrogen for 18h. The dichloromethane was removed in vacuo and the solid residue partitioned between ethyl acetate (100ml) and 0.5M citric acid (150ml). The organic layer was retained and washed succesively with 0.5M citric acid (100ml) saturated sodium bicarbonate solution (2 x 150ml) and brine (100ml) before drying (Na 2 SO 4 ). The solvent was removed by rotary evaporation and the solid residue recrystallised from ethyl acetate/hexane to give the title compound as colourless crystals (2.61g) m.p. 155-157°C. Step b: Trans-2-methoxycarbonyl-5,7-dichloro-4-(4-iodophenyl) aminocarbonylamino-1,2,3,4-tetrahydroquinoline To a solution of 1-phenyl-3-(4-iodophenyl)carbamate (770mg, 7.61mmol), in anhydrous toluene (15ml) was added dry triethylamine (0.670ml, 4.33mmol). The solution was heated, with stirring, in an oil bath to 120°C and then allowed to cool to (0.55ml, 4.33mmol). The solution was heated at reflux (120°C) for 2h. The mixture was cooled below 30°C and a solution of trans -2-methoxycarbonyl-5,7-dichloro-4-amino-tetrahydroquinoline-hydrochloride (example 1a) (750mg, 2.41mmol) was added as a solution in anhydrous dichloromethane (10ml) with triethylamine (0.403ml, 2.87mmol). The mixture was stirred under an atmosphere of nitrogen for 18h. The organic solvents were removed in vacuo and the solid residue partitioned between 0.5M citric acid (100ml) and ethyl acetate (100ml). The organic layer was retained and washed succesively with 0.5M citric acid (100ml), saturated sodium bicarbonate solution (2 x 100ml) and brine (100ml) before drying (Na 2 SO 4 ). The solvent was removed and the product recrystallised from ethyl acetate/hexane to give the title compound as colourless crystals (668mg), m.p. 253-255°C. Step c: Trans-2-carboxy-5,7-dichloro-4-(4-iodophenyl) aminocarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 8 step b using trans -2-methoxycarbonyl-5,7-dichloro-4(4-iodophenylaminocarbonyl)amino-1,2,3,4-tetrahydroquinoline in place of trans -2-methoxycarbonyl-5,7-dichloro-4(phenylaminocarbonyl)amino-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals, m.p. 224-226°C. EXAMPLE 47 Trans-2-carboxy-5,7-dichloro-4-(phenyl)aminocarbonyl-N-methylamino)-1,2,3,4-tetrahydroquinoline Step a: Trans-2-methoxycarbonyl-5,7-dichloro-4-N-methylamino-1,2,3,4-tetrahydroquinoline Trans -2-carboxy-5,7-dichloro-4-amino-1,2,3,4-tetrahydroquinoline hydrochloride (Example 1a) (760mg, 2.44mmol) was shaken with a solution of potassium carbonate for 5 min. The solid in suspension was extracted into ethyl acetate (2 x 50ml). The combined organic extracts were evaporated and the solid residue redissolved in anhydrous tetrahydrofuran (300ml). This solution was cooled (-5°C) and a solution of methyl iodide (159µl, 2.56mmol) in tetrahydrofuran (50ml) was added dropwise, under an atmosphere of nitrogen. The mixture was allowed to warm to room temperature and was stirred for 70h. The THF was removed and the solid residue redissolved in 30ml of THF. A further quantity of methyl iodide (159µl, 2.56mmol) was added as a solution in THF (5ml) and the mixture stirred for a further 16h in an atmosphere of nitrogen. The solvent was evaporated and the residue separated by silica chromatography (eluent; methanol/dichloromethane) to yield the title compound as a colourless crystalline solid. Step b: Trans-2-carboxy-5,7-dichloro-4-(phenyl) aminocarbonyl-N-(methylamino)-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 8 using trans -2-methoxycarbonyl-5,7-dichloro-4-N-methylamino-1,2,3,4-tetrahydroquinoline in place of trans -2-methoxycarbonyl-5,7-dichloro-4-amino- 1,2,3,4-tetrahydroquinoline hydrochloride and triethylamine, to give the title compound as colourless crystals, m.p. 139-140°C. EXAMPLE 48 Trans-2-carboxy-5,7-dichloro-4-(-N-methyl)-(N-phenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline Step a: Trans-2-methoxycarbonyl-5,7-dichloro-4-(phenyloxy)carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 6, step a, using phenylchloroformate in the place of butyryl chloride to give the title compound as colourless crystals, m.p. 159-161°C. Step b: Trans-2-methoxycarbonyl-5,7-dichloro-4(N-methyl)-(N-phenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline To a solution of trans -2-methoxycarbonyl-5,7-dichloro-4-(phenyloxy)carbonylamino-1,2,3,4-tetrahydroquinoline (225mg, 0.587mmol) in anhydrous toluene (7ml) was added dry triethylamine (245µl, 1.76mmol). The mixture was heated with stirring, in an oil bath to 120°C and then allowed to cool to (186µl, 1.47mmol). The solution was heated at reflux (120°C) for 2h. After cooling to triethylamine was added (81µl, 0.587mmol) followed by N-methylaniline (126mg, 1.174mmol). The mixture was stirred at room temperature under an atmosphere of nitrogen for 18h. The organic solvent was removed and the solid residue paritioned between ethyl acetate (75ml) and 0.5M citric acid (100ml). The organic layer was retained and washed successively with 0.5M citric acid (100ml), saturated sodium bicarbonate solution (2 x 100ml) and brine (100ml) before drying (Na 2 SO 4 ). The solvent was removed in vacuo to yield an orange oil which was isolated by flash chromatography (solvent; ethyl acetate/hexane) to give the title compound as colourless crystals (89mg) m.p. 185-189°C. Step c: Trans-2-carboxy-5,7-dichloro-4-(N-methyl)-)N-phenyl)amino)carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 8, step b, using trans -2-methoxycarbonyl-5,7-dichloro-4-(N-methyl)-(N-phenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline in place of trans-2-methoxycarbonyl-5,7-dichloro-4(phenyl)N-methylaminocarbonylamino-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals, m.p. 204-205°C. EXAMPLE 49 Trans-2-carboxy-5,7-dichloro-4-(2,3-dihydroindole-1-carbonyl)amino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 48 using indoline in place of N-methylaniline to give the title compound as colourless crystals, m.p. 251-252°C. EXAMPLE 50 Trans-2-carboxy-5,7-dichloro-4-(2-carboxyethyl)carbonyl)amino-1,2,3,4-tetrahydroquinoline Step a: trans-2-methoxycarbonyl-5,7-dichloro-4-(2-carboxyethyl)carbonylamino-1,2,3,4-tetrahydroquinoline To a suspension of trans -2-methoxycarbonyl-5,7-dichloro-4-amino-1,2,3,4-tetrahydroquinoline hydrochloride (Example 1a) (225mg, 0.819mmol) in ethyl acetate (50ml) was added a solution of potassium carbonate (50ml). The mixture was shaken until no solid remained (5min). The organic layer was retained and washed with brine (50ml) before drying (Na 2 SO 4 ). The solvent was removed in vacuo . The residue was redissolved in xylene (20ml) and succinic anhydride (90mg, 0.901mmol) was added. The mixture was heated, with stirring, in an oil bath (80°C) for 16h. The precipitate was removed by filtration and washed with ether to give the title compound as a colourless crystalline solid. Step b: Trans-2-carboxy-5,7-dichloro-4-(2-carboxyethyl)carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 6, step b, using trans -2-methoxycarbonyl-5,7-dichloro-4-(2-carboxyethyl)carbonylamino-1,2,3,4-tetrahydroquinoline in place of trans -2-methoxycarbonyl-5,7-dichloro-4-butylcarbonylamino-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals, m.p. 221-223°C. EXAMPLE 51 Trans-2-carboxy-5,7-dichloro-4-(3-aminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride Step a: 3-(tert-Butyloxycarbonylamino)methyl benzoic acid To a solution of 3-cyanobenzoic acid (1.0g, 6.79mmol) in ethanol (150ml) was added 100mg of 10% palladium on carbon and the mixture was hydrogenated at 50 psi for approximately 18h. Di-tert-butyl dicarbonate (1.63g, 7.47mmol) was added to the mixture, with a further 110mg of catalyst and hydrogenation was continued under the same conditions for a further 20h. After this time all the starting material had been consumed by t.l.c. (solvent: 1% MeOH, 0.5% AcoH, 98.5% CH 2 Cl 2 ). The catalyst was removed by filtration, and the ethanol was removed by rotary evaporation to give an orange oil which crystallised after drying under high vacuum (1h). The product was recrystallised from ether/hexane to give the title compound as colourless crystals, m.p. 127-128°C. Step b: Trans-2-methoxycarbonyl-5,7-dichloro-4-(3-tert-butyloxycarbonylaminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline To a suspension of 2-methoxycarbonyl-5,7-dichloro-4-amino-1,2,3,4-tetrahydroquinoline hydrochloride (Example 1) (300mg, 0.963mmol) in anhydrous dichloromethane (15ml) under an atmosphere of nitrogen was added dry triethylamine (403µl, 2.89mol) and the resulting mixture was stirred at room temperature for 5 min. To this was added 3-(tert-butyloxycarbonylamino)methyl benzoic acid (step a) (290mg, 1.16mmol), 1-hydroxybenzotriazole (156mg, 1.16mol) followed by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (222mg, 1.16mmol) and stirring was continued for approximately 18h. The mixture was then concentrated in vacuo and the residue partitioned between ethyl acetate (100ml) and 0.5M citric acid (150ml). The organic layer was retained and washed successively with 0.5M citric acid (150ml), saturated sodium bicarbonate solution (2 x 150ml) and brine (100ml) before drying (Na 2 SO 4 ). The solvent was removed and the residue was recrystallised from ethyl acetate/hexane to give the title compound as colourless crystals (351mg), m.p. 222-223°C. Step c: Trans-2-carboxy-5,7-dichloro-4-(3-tert-butyloxycarbonylaminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline To a solution of trans -2-methoxycarbonyl-5,7-dichloro- 4-(3-tert-butyloxycarbonylaminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline (step b) (430mg, 0.846mmol) in a mixture of tetrahydrofuran (20ml) and water (10ml) was added aqueous lithium hydroxide (1.95ml of a 0.5M solution, 0.973mmol), and the resulting mixture was stirred at room temperature for 3h. The organic solvent was removed in vacuo and the aqueous residue was diluted to 50ml before acidifying to pH 1 with 1N HCl. The white precipitate was extracted into ethyl acetate (150ml), washed with brine and dried (Na 2 SO 4 ). The solution was evaporated to give a residue which was washed with diethyl ether and collected by filtration to give the title compound as a colourless crystalline solid, m.p. 192-193°C. Step d: Trans-2-carboxy-5,7-dichloro-4-(3-aminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride To a solution of trans -2-carboxy-5,7-dichloro-4-(3-tert-butyloxycarbonylaminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline (85mg) in ethyl acetate (20ml) was added 25ml of ethyl acetate saturated with hydrogen chloride gas and the mixture was stirred in a stoppered flask for 6h. The ethyl acetate and excess hydrogen chloride were removed in vacuo and the solid residue was recrystallised from ethyl acetate/methanol to give the title compound as colourless crystals (46mg), m.p. 199-200°C. EXAMPLE 52 Trans-2-methoxycarbonyl-5,7-dichloro-4-(3-aminomethylphenyl) carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride A solution of hydrogen chloride in methanol was prepared by the cautious addition of acetyl chloride (6ml) to ice-cooled methanol (25ml). Trans -2-carboxy-5,7-dichloro-4-(3-aminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride (87mg, 0.202mmol) (Example 51) was dissolved in the HCl/methanol solution and the resulting mixture was stirred in a stoppered flask for 2h. The methanol and excess hydrogen chloride were removed in vacuo and the product recrystallised from methanol/ether to give the title compound as a colourless crystalline solid (80mg) m.p. 173°C (dec). EXAMPLE 53 Trans-2-carboxy-5,7-dichloro-4-(4-aminomethylphenyl) carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride step a: 4-(tert-Butyloxycarbonylamino)methyl benzoic acid To a stirred suspension of 4-aminomethyl benzoic acid (5.0g, 0.0331mol) in 10% sodium carbonate solution (42ml, 0.0394mol) was added a solution of di-tert-butyl dicarbonate (7.43g, 0.0364mol) in dioxan (42ml) and the mixture was stirred at room temperature for 2h. The mixture was diluted with water to 300ml and washed with ether (100ml). The aqueous fraction was retained and acidified to pH3 with 1N citric acid solution. The precipitate was extracted into ethyl acetate, washed with water (2 x 100ml), brine (1 x 100ml) and dried (Na 2 SO 4 ). The solvent was removed in vacuo to give a white solid m.p. 170-171°C. Step b: Trans-2-carboxy-5,7-dichloro-4- (4-aminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given for Example 51, steps b, c, and d, using 4-(tert-butyloxycarbonylamino)methyl benzoic acid in place of 3-(tert-butyloxycarbonylamino)methyl benzoic acid to give the title compound as colourless crystals, m.p. 219°C (dec). EXAMPLE 54 Trans-2-methoxycarbonyl-5,7-dichloro-4-(4-aminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given for Example 52 using trans -2-carboxy-5,7-dichloro-4(4-aminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride, Example 53, in place of trans -2-carboxy-5,7-dichloro-4(3-aminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride to give the title compound as a colourless crystalline solid m.p. 238-240°C. EXAMPLE 55 Trans-2-carboxy-5,7-dichloro-4-(4-aminoethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride step a: (4-tert-Butyloxycarbonylamino)ethyl benzoic acid To a suspension of 4-aminoethylbenzoic acid hydrochloride (4.32g, 0.0214mol), in anhydrous dichloromethance (50ml) was added triethylamine (8.94ml, 0.0642mol) and the mixture was stirred at room temperature for 10 min. To this solution was added di-tert-butyl-dicarbonate (5.14g, 0.236mol) and stirring was continued for 18h. Dimethyl ethylenediamine (2ml) was added and after stirring for a further 20 min the dichloromethane was removed in vacuo . The residue was partitioned between ethyl acetate (150ml) and 0.5M citric acid (100ml). The organic layer was retained and washed successively with 0.5M citric acid (100ml), water (3 x 150ml) and brine (100ml) before drying (Na 2 SO 4 ). The solvent was removed in vacuo and the residue recrystallised from ethyl acetate/hexane to give the title compound as a colourless crystalline solid, m.p. 163-164°C. step b: Trans-2-carboxy-5,7-dichloro-4-(4-aminoethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given for Example 51, steps b, c, and d, using 4-(tert-butyloxycarbonylamino)ethyl benzoic acid as the starting material in the place of 3-(tert-butyloxycarbonylamino)methyl benzoic acid to give the title compound as colourless crystals, m.p. 204°C (dec). EXAMPLE 56 Trans-2-methoxycarbonyl-5,7-dichloro-4-(4-aminoethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given for Example 52 using trans -2-carboxy-5,7-dichloro-4-(4-aminoethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride Example 55, in the place of trans -2-carboxy-5,7-dichloro-4(3-aminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride to give the title compound as a colourless crystalline solid, m.p. 218°C (dec). EXAMPLE 57 Trans-2-carboxy-4-(3-methylphenyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 7 using 3-methylphenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 169-171°C. EXAMPLE 58 Trans-2-carboxy-5,7-dichloro-4-(3-nitrophenyl)methylcarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared using the same method given for Example 7 using 3-nitrophenylacetic acid in place of phenylacetic acid to give the title compound as yellow crystals, m.p. 260°C. EXAMPLE 59 Trans-2-carboxy-5,7-dichloro-4-(3-methoxyphenyl)methylcarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the same method given for Example 6 using 3-methoxyphenylacetyl chloride in place of butyryl chloride to give the title compound as colourless crystals, m.p. 242-244°C. EXAMPLE 60 Trans-2-carboxy-4-(1-naphthyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 7 using 1-naphthylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 257-258°C. EXAMPLE 61 Trans-2-carboxy-4-(2-naphthyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 7 using 2-naphthylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 217-219°C. EXAMPLE 62 Trans-2-carboxy-4-(3-thiophenyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 7 using 3-thiopheneacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 198-200°C. EXAMPLE 63 Trans-2-carboxy-4-(2,6-dichlorophenyl)methylcarbonyl amino-5,7-dichloro-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 7 using 2,6-dichlorophenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 235-237°C. EXAMPLE 64 Trans-2-carboxy-4-(phenylamino)thiocarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given for Example 8 using phenylisothiocyanate in place of phenylisocyanate to give the title compound as colourless crystals, m.p. 186-187°C. EXAMPLE 65 Trans-2-carboxy-4-phenylmethoxycarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline Trans -4-amino-2-methoxycarbonyl-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride (Example 1a) (0.3g, 0.00096ml) was dissolved in dichloromethane (30ml) together with triethylamine (0.4ml, 3 molar equivalents) and dibenzyl dicarbonate (0.33g, 1.2molar equivalents). The reaction mixture was stirred at room temperature for 14h then dimethylethylenediamine (0.3ml) was added and the reaction stirred for a further 2h. The solvents were removed by evaporation and the residue redissolved in ethyl acetate (40ml) and washed with 1 molar citric acid solution (2 x 30ml), saturated sodium hydrogen carbonate solution (2 x 30ml) and brine (1 x 30ml). The organic layer was dried (Na 2 SO 4 ), filtered and concentrated in vacuo to leave a residue which was purified by chromatography on silica gel using 20% ethyl acetate in hexane as eluent to give a white solid (0.24g). This was suspended in 50% aqueous methanol (100ml) and stirred at room temperature for 60h in the presence of sodium hydroxide (0.2g). The methanol was removed in vacuo and the aqueous residue acidified to pH 1 with 1M hydrochloric acid. The solid which was precipitated was extracted into ethyl acetate (2 x 50ml), washed with brine (1 x 40ml), dried (Na 2 SO 4 ), filtered and concentrated in vacuo . The residue was recrystallised from diethyl ether/hexane to give the title compound as colourless crystals, m.p. 169°C. EXAMPLE 66 Trans-2-carboxy-5,7-dichloro-4-(3-methoxyphenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 8 using 3-methoxyphenylisocyanate in place of phenylisocyanate to give the title compound as colourless crystals, m.p. 181-183°C. EXAMPLE 67 Trans-2-carboxy-5,7-dichloro-4-(3-methylphenyl) aminocarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 8 using 3-methylphenylisocyanate instead of phenylisocyanate to give the title compound as colourless crystals, m.p. 172-174°C. EXAMPLE 68 Trans-2-carboxy-5,7-dichloro-4-(3-chlorophenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method outlined in Example 8 using 3-chlorophenylisocyanate instead of phenylisocyanate to give the title compound as colourless crystals, m.p. 173-175°C. EXAMPLE 69 Trans-2-carboxy-5,7-dichloro-4-(3-nitrophenyl) aminocarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 8 using 3-nitrophenylisocyanate instead of phenylisocyanate to give the title compound as yellow crystals, m.p. 209-210°C. EXAMPLE 70 Trans-2-carboxy-4-(3-aminopropyl)carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride a) 4-(Tertiarybutyloxycarbonylamino)butanoic acid 4-Amino butyric acid (2.06g, 0.02M) was suspended in a solution of tetrahydrofuran (30ml) and dichloromethane (20ml) with triethylamine (2.77ml, 1 molar equivalent) and ditertiarybutyl dicarbonate (4.36g, 1 molar equivalent) was added. After stirring at room temperature for 14h the solvents were evaporated and the residue was chromatographed on silica gel using 1% acetic acid, 4% methanol and 95% dichloromethane as eluent to give the required compound (1.9g) as an oily solid. b) Trans-2-carboxy-4-(3-aminopropyl)carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride 4-(Tertiarybutyloxycarbonylamino)butanoic acid (0.3g, 1.5 molar equivalents), 2-methoxycarbonyl-5,7-dichloro-4-amino-1,2,3,4-tetrahydroquinoline hydrochloride (Example 1a) (0.3g, 0.000963M), hydroxybenzotriazole (0.156g, 1.2 molar equivalents) and triethylamine (0.4ml, 3 molar equivalents) were dissolved in anhydrous tetrahydrofuran (40ml) followed by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.22g, 1.2 molar equivalents). After stirring at room temperature for 14h the solvents were evaporated, the residue was dissolved in ethyl acetate (100ml) and washed with 0.5M citric acid solution (2 x 50ml), saturated sodium hydrogen carbonate solution (2 x 50ml) and brine (1 x 50ml). The organic layer was dried (Na 2 SO 4 ), filtered and concentrated in vacuo to leave a residue which was dissolved in 50% aqueous methanol and treated with sodium hydroxide (0.5g). After stirring the solution for 36h at room temperature the methanol was removed under vacuum and the residual aqueous solution was treated with 1M HCl until a pH of 1 was attained. The precipitated solid was extracted into ethyl acetate (2 x 20ml) and the combined organic layers were dried (Na 2 SO 4 ), filtered and concentrated in vacuo . The residue obtained was treated with 5 molar HCl in ethyl acetate (30ml) and stirred at room temperature for 60h. The solvents were evaporated and the residue recrystallised from methanol/diethyl ether/ethyl acetate to give the title compound as a white crystalline solid, m.p. 238-240°C. EXAMPLE 71 Trans-2-carboxy-4-(3-aminoethyl)carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method described in Example 70b using 3-(tertiarybutyloxycarbonylamino)-propanoic acid instead of 4-(tertiarybutyloxycarbonylamino)-butanoic acid to give the title compound as colourless crystals, m.p. 214-215°C. EXAMPLE 72 Trans-2-carboxy-4-(4-aminobutyl)carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method described in Example 70a and 70b using 5-amino valeric acid instead of 4-aminobutyric acid to give the title compound as colourless crystals, m.p. 160°C (dec). EXAMPLE 73 Trans-2-carboxy-4-(4-piperidylmethyl)carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method described in Example 70a and 70b using 4-piperidine acetic acid in place of 4-aminobutyric acid to give the title compound as colourless crystals, m.p. 175°C (dec). EXAMPLE 74 Trans-2-carboxy-4-(4-aminomethylphenyl)methyl-carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the route outlined in Example 70a and 70b using 4-aminomethylphenylacetic acid in place of 4-aminobutyric acid to give the title compound as colourless crystals, m.p. 248-250°. EXAMPLE 75 Trans-2-methoxycarbonyl-4-(4-aminomethylphenyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given in Example 52 using trans -2-carboxy-4(-4-aminomethylphenyl)-methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride (Example 74) in place of trans -2-carboxy-4(3-aminomethylphenyl)carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride to give the title compound as colourless crystals, m.p. 172-174°C. EXAMPLE 76 Trans-4-(4-aminoethylphenyl)methylcarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride Step a Methyl-4-tertiary-butyloxycarbonylamino ethylphenylacetate To a solution of 4-cyanomethylphenylacetic acid (1.0g, 5.7mmol) in a mixture of water (150ml), 15% aqueous potassium hydroxide (20ml) and concentrated aqueous ammonia (50ml) was added a slurry of Raney nickel in water (approx. 0.5g) and the resulting mixture was hydrogenated at room temperature under 50 psi for 2.25h. The mixture was then filtered and evaporated to dryness in vacuo . The residue was then dissolved in water (100ml), acidified with concentrated hydrochloric acid, washed with ethyl acetate (2 x 75ml) and the aqueous phase was freeze- dried to give a solid. To a solution of this solid in a mixture of water (40ml) and 1,4-dioxan (40ml) was added anhydrous sodium carbonate (2.01g, 19.9mmol) and di-tertiary-butyldicarbonate (2.62g, 12.0mmol) and the mixture was stirred at room temperature for 2 hours. The organic solvent was then removed under vacuum and the aqueous residue was diluted with water (100ml) and washed with diethyl ether (2 x 75ml). The aqueous phase was acidified with concentrated hydrochloric acid and extracted with ethyl acetate (2 x 75ml). The combined extracts were washed with saturated brine solution (1 x 75ml), dried (MgSO 4 ) and evaporated to give the crude intermediate as an oil. This preparation was repeated using 1.13g of 4-cyanomethylphenylacetic acid (6.46mmol) and the resulting oil was combined with that from above. To a solution of this crude material in diethyl ether (300ml) was added a solution of diazomethane (16mmol) in diethyl ether (80ml) and the mixture was allowed to stand at room temperature for 0.25h. The reaction was then quenched with glacial acetic acid (0.5ml) and the mixture was washed with saturated sodium bicarbonate solution (3 x 100ml), saturated brine solution (1 x 100ml), dried (MgSO 4 ) and evaporated. The resulting solid was purified using flash chromatography (using 30% ethyl acetate in petroleum ether bp 60-80° as eluent) to give the title compound as colourless crystals (3.00g), m.p. 77-78°C. Step b 4-Tertiary-butyloxycarbonylaminoethylphenylacetic acid To a solution of methyl 4-(tertiarybutyloxycarbonylaminoethyl)phenylacetate (0.500g, 1.71mmol) in a mixture of tetrahydrofuran (20ml) and water (10ml) was added aqueous lithium hydroxide (3.8ml of a 0.50M solution, 1.90mmol) and the resulting mixture was stirred at room temperature for 16h. The organic solvent was removed under vacuum and the residue was diluted with water (40ml), acidified with concentrated hydrochloric acid and extracted with ethyl acetate (2 x 30ml). The combined extracts were washed with brine (1 x 30ml), dried (MgSO 4 ) and evaporated to give the pure title compound as colourless crystals (0.460g), m.p. 94-95°C. Step c . Trans-(4-(4-tertiary-butyloxycarbonylaminoethylphenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline This material was prepared using the method given for Example 7 Step a using 4-(tertiarybutyloxycarbonylaminoethyl)phenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 219-221°C. Step d . Trans-4-(4-aminoethylphenyl)methylcarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride To a solution of trans -4(4-tertiary-butyloxycarbonyl aminoethylphenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline (0.095g, 0.177mmol) in a mixture of tetrahydrofuran (10ml) and water (5ml) was added aqueous lithium hydroxide (0.40ml of a 0.50M solution, 0.20mmol) and the resulting mixture was stirred at room temperature for 1h. The organic solvent was then removed under vacuum, and the residue was diluted with sodium bicarbonate solution (40ml) and washed with diethyl ether (1 x 30ml). The aqueous phase was then acidified with concentrated hydrochloric acid and extracted with ethyl acetate (2 x 40ml). The combined extracts were washed with brine (1 x 40ml), dried (MgSO 4 ) and evaporated to give an oil. To a solution of this oil in ethyl acetate (5ml) was added a saturated solution of hydrogen chloride in ethyl acetate (5ml) and the mixture was stirred at room temperature for 35 min. The solid was collected by filtration, washed with ethyl acetate and dried to give the title compound as colourless crystals (0.075g), m.p. 142-145°C. EXAMPLE 77 Trans-4-(4-aminoethylphenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride To a solution of trans -4(4-tertiary-butyloxycarbonylaminoethylphenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline (Example 76c) (0.150g, 0.28mmol) in ethyl acetate (5ml) was added a saturated solution of hydrogen chloride in ethyl acetate (5ml) and the resulting mixture was stirred at room temperature for 40 minutes. The solvent was then removed under vacuum and the residue was triturated with hot ethyl acetate. A gummy solid was collected by filtration and this was dissolved in water and freeze dried to give the title compound as a colourless solid (0.121g), m.p. decomposes above 200°C. EXAMPLE 78 Trans-2-carboxy-5,7-dichloro-4-(4-N-methylaminomethylphenyl)methyl-carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride Step a) 4-N-tertiary-butyloxycarbonyl-N-methylaminomethylphenylacetic acid To a solution of 4-(bromomethyl)phenylacetic acid (8.58g, 37.5mmol) in anhydrous N,N-dimethylformamide (200ml) was added methylamine hydrochloride (25.3g, 375mmol) and dry triethylamine (63.0ml, 450mmol). The resulting mixture was stirred under an atmosphere of nitrogen at room temperature for 16.5h. The reaction was then concentrated in vacuo and the resulting residue was partitioned between ethyl acetate (200ml) and 1M hydrochloric acid (200ml). The aqueous layer was separated, washed with ethyl acetate (200ml) and the pH adjusted to 14 by the addition of solid sodium hydroxide. The alkaline solution was washed with diethyl ether (2 x 100ml), then reacidified with concentrated hydrochloric acid and evaporated in vacuo to give the crude amino acid hydrochloride as a mixture with inorganic material. To a solution of this solid in water (100ml) was added 1,4-dioxan (100ml), sodium carbonate (13.1g, 124mmol) and di-tertiarybutyldicarbonate (18.0g, 82mmol) and the reaction was stirred at room temperature for 3h. The organic solvent was removed under vacuum and the aqueous residue was washed with diethyl ether (2 x 75ml), acidified by the addition of concentrated hydrochloric acid and extracted with ethyl acetate (2 x 75ml). The combined extracts were washed with brine (1 x 75ml), dried (MgSO 4 ) and evaporated in vacuo to give the crude N-protected amino acid as an oil (0.91g) To a solution of this oil (0.91g, 3.3mmol) in ethanol (50ml) at room temperature was added sufficient of a solution of diazomethane (∼ 5mmol) in diethyl ether (∼ 90ml) to allow a yellow colour to persist. The excess diazomethane was then destroyed by the addition of glacial acetic acid (1ml) and the mixture was concentrated in vacuo . The residue was dissolved in diethyl ether (5ml), washed with saturated sodium bicarbonate solution (3 x 25ml), brine (1 x 25ml), dried (MgSO 4 ) and evaporated to give an oil which was purified by flash chromatography on silica gel using a gradient of 10-15% ethyl acetate in petroleum ether bp (60-80°) as eluent, to give the pure fully protected amino acid as a clear oil (0.549g). To a solution of this oil (0.532g, 1.82mmol) in a mixture of tetrahydrofuran (30ml) and water (15ml) was added aqueous lithium hydroxide (4.0ml of a 0.50M solution) and the reaction was stirred at room temperature for 3h. The organic solvent was removed under vacuum and the aqueous mixture was diluted with water (40ml), acidified with concentrated hydrochloric acid and extracted with ethyl acetate (2 x 25ml). The combined extracts were washed with brine (1 x 25ml), dried (MgSO 4 ) and evaporated in vacuo to give the title compound as colourless crystals (0.50g), mp 122-125°C. Step b) Trans-4-(4-N-tertiary-butyloxycarbonyl-N-methylaminomethylphenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline This material was prepared using the method given for Example 7, Step a) using 4-N-tertiary-butyloxycarbonyl-N-methylaminomethylphenylacetic acid in place of phenylacetic acid, yielding the crude product which was purified by flash chromatography on silica gel, using 45% ethyl acetate in petroleum ether bp (60-80°). Recrystallisation from ethyl acetate-petroleum ether bp (60-80°) gave the title compound as colourless crystals, mp 128-129.5°C. Step c) Trans-2-carboxy-5,7-dichloro-4-(4-N-methylaminomethylphenyl)methylcarbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride This material was prepared using the method given for Example 76, Step d) using trans -4-(4N-tertiary-butyloxy-carbonyl-N-methylaminomethylphenyl)methylcarbonylamino-5,7-dichloro-2- methoxycarbonyl-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals, mp 140°C dec. EXAMPLE 79 Trans-5,7-dichloro-2-methoxycarbonyl-4(4-N-methylaminomethylphenyl)methylcarbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride This material was prepared using the method given for Example 77 using trans -4-(4-N- tertiary -butyloxycarbonyl-N-methylaminomethylphenyl) methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline in place of trans-4-(4-tertiary-butyloxycarbonylaminoethylphenyl)-methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals, mp. 140°C dec. EXAMPLE 80 Trans-5,7-dichloro-4-(4-N,N-dimethylamino-methylphenyl) methylcarbonylamino-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline Step a) Ethyl 4-(tertiary-butyloxycarbonylaminomethyl)phenylacetate To a refluxing suspension of 4-(bromomethyl)phenylacetic acid (20.63g, 90.1mmol) in chloroform (160ml) was slowly added a solution of hexamethylenetetramine (13.4g, 95.5mmol) in chloroform (110ml). The resulting mixture was heated at reflux under an atmosphere of nitrogen for 2.5h, then cooled to room temperature and the colourless solid which had formed was collected by filtration. A solution of this solid in a mixture of concentrated hydrochloric acid (50ml) and ethanol (140ml) was heated at reflux for 1h, then cooled, filtered and the filtrate was concentrated in vacuo to yield an oily solid. This solid was dissolved in ethanol (300ml) and the solution was saturated with hydrogen chloride gas with cooling in ice then stirred at room temperature for 18h. After evaporation of the solvent under vacuum, the residue was dissolved in water (500ml) and washed with ethyl acetate (2 x 200ml). The aqueous phase was separated, basified with solid sodium bicarbonate, extracted with ethyl acetate (3 x 200ml), then basified further with solid sodium carbonate and again extracted with ethyl acetate (5 x 100ml). The combined extracts were washed with brine (1 x 300ml), dried (MgSO 4 ) and evaporated to give the crude amine ester as an oil (13.5g). To a solution of this oil (13.5g) in dichloromethane (350ml) was added di-tertiary-butyldicarbonate (21.0g, 96mmol) and the resulting mixture was stirred at room temperature under an atmosphere of nitrogen for 4h. To the reaction was then added N,N-dimethylethylenediamine (8.4ml, 76mmol) and stirring was continued for 0.5h. The mixture ws then washed successively with 1M aqueous citric acid (2 x 700ml), saturated aqueous sodium bicarbonate solution (2 x 700ml), brine (1 x 200ml) then dried (MgSO 4 ) and evaporated to give a brown oil. This was purified by flash chromatography on silica gel using 20% ethyl acetate in petroleum ether bp (60-80°) as eluent to yield the title compound as a colourless oil (13.46g). Step b) Ethyl 4-(aminomethyl)phenylacetate hydrochloride To a solution of ethyl 4-(tertiary-butyloxycarbonylaminomethyl)phenylacetate (1.50g, 5.1mmol) in ethyl acetate (10ml) was added a saturated solution of hydrogen chloride in ethyl acetate (20ml) and the resulting mixture was stirred at room temperature in a stoppered flask for 2h. The reaction was then concentrated in vacuo and the solid residue was triturated with hot ethyl acetate and collected by filtration to give the title compound as colourless crystals (1.11g), mp 184-186°C. Step c) Ethyl 4-(N,N-dimethylaminomethyl)phenylacetate A solution of ethyl 4-(aminomethyl)phenylacetate hydrochloride (2.00g, 8.71mmol) in water (100ml) was basified by the addition of sodium carbonate, then saturated with sodium chloride and extracted with ethyl acetate (3 x 50ml). The combined extracts were dried (MgSO 4 ) and evaporated to give an oil. To a solution of this oil in acetonitrile (50ml) was added aqueous formaldehyde (3.5ml of a 37% solution, 43mmol) and sodium cyanoborohydride (approx. 0.9g, 14mmol) and the resulting cloudy mixture was stirred at room temperature for 0.5h. Sufficient glacial acetic acid to give a pH of 5 (when tested on wet indicator paper) was then added and stirring was continued for 1.2h. The reaction was quenched with dilute aqueous sodium carbonate (50ml), and the organic solvent was removed under vacuum to give an aqueous residue which was extracted with ethyl acetate (3 x 20ml). The combined extracts were concentrated in vacuo and partitioned between 1M hydrochloric acid (75ml) and diethyl ether (30ml). The aqueous phase was separated, washed with ethyl acetate (2 x 30ml) then basified with sodium carbonate, saturated with sodium chloride and extracted with ethyl acetate (3 x 20ml). The combined extracts were washed with saturated brine (30ml), dried (MgSO 4 ) and evaporated to give the title compound as an oil (0.545g). Step d) 4-(N,N-dimethylaminomethyl)phenylacetic acid To a solution of ethyl 4-(N,N-dimethylaminomethyl) phenylacetate (0.470g, 2.13mmol) in a mixture of tetrahydrofuran (15ml) and water (5ml) was added aqueous lithium hydroxide (4.7ml, 2.34mmol) and the resulting mixture was stirred at room temperature for 4h. The organic solvent was removed under vacuum and the aqueous residue was freeze dried to give the crude lithium salt. This material was applied to an ion-exchange resin (Dowex 50W x 8), eluted with dilute aqueous ammonia and freeze dried to give the title compound as a non-crystalline solid (0.368g). Step e) Trans-5,7-dichloro-4-(4-N,N-dimethylaminomethylphenyl) methylcarbonylamino-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline A solution of trans -4-amino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride (0.35g, 1.12mmol) in water (50ml) was basified with sodium carbonate, saturated with sodium chloride and extracted with ethyl acetate (2 x 30ml). The combined extracts were washed with brine (1 x 30ml), dried (MgSO 4 ) and evaporated to give the free base as a solid (0.28g). To a solution of this material (0.28g, 1.02mmol) in anhydrous tetrahydrofuran (30ml) were added 4-N,N-dimethylaminomethylphenylacetic acid (0.216g, 1.12mmol), 1-hydroxybenzotriazole (0.151g, 1.12mmol) and N,N'-dicyclohexylcarbodiimide (0.231g, 1.12mmol) and the resulting mixture was stirred at room temperature under an atmosphere of nitrogen for 18h. The reaction was concentrated in vacuo and the residue was suspended in ethyl acetate (50ml) and extracted with 1M hydrochloric acid (4 x 20ml). The combined aqueous extracts were washed with ethyl acetate (1 x 20ml), filtered, basified with sodium carbonate, saturated with sodium chloride and extracted with ethyl acetate (3 x 20ml). The combined extracts were washed with brine (20ml), dried (MgSO 4 ) and evaporated under vacuum to give the crude product which was purified by flash chromatography on silica gel using dichloromethane containing 8% methanol and 0.1% ammonia as eluent, followed by recrystallisation from ethyl acetate/petroleum ether bp (60-80°), to give the title compound as colourless crystals (0.261g), mp 182-183°C. EXAMPLE 81 Trans-2-carboxy-5,7-dichloro-4(4-N,N-dimethylaminomethylphenyl)methylcarbonylamino-1,2,3,4-tetrahydroquinoline To a solution of trans-5,7-dichloro-4(4-N,N-dimethylaminomethylphenyl)methylcarbonylamino-2-methoxycarbonyl- 1,2,3,4-tetrahydroquinoline (Example 80, 0.120g, 0.267mmol) in a mixture of tetrahydrofuran (10ml) and water (5ml) was added aqueous lithium hydroxide (0.58ml of a 0.50M solution, 0.29mmol) and the resulting mixture was stirred at room temperature for 2h. The reaction was then evaporated to dryness in vacuo to give a solid which was applied to an ion-exchange resin (Dowex 50W x 8), and eluted with dilute aqueous ammonia. The solution was then freeze dried to give the crude product which was triturated with hot methanol and collected by filtration to yield the title compound as a colourless solid (0.032g), mp 190-193°C. EXAMPLE 82 Trans-2-carboxy-4-(4-(3-aminoprop-2-ynyl)phenyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride a) 4-(3-Hydroxyprop-2-ynyl)phenylacetic acid methyl ester 4-Bromophenylacetic acid methyl ester (23g, 0.1mol) was dissolved in dry triethylamine (80ml) with propynol (5.82ml, 0.1mol). After the addition of cuprous iodide (0.3g) and bis (triphenylphosphine)palladium (II) chloride (1g) the reaction mixture was heated at 65°C under nitrogen for 14h. The solvent was evaporated under vacuum and the residue was dissolved in ethyl acetate (500ml) and washed successively with 0.5M citric acid solution (2 x 200ml), saturated sodium hydrogen carbonate solution (2 x 200ml) and brine (1 x 150ml). The organic solution was dried (Na 2 SO 4 ), filtered and concentrated in vacuo to give an oil which was purified by chromatography on silica gel using 20% ethyl acetate in hexane as eluent to give the required compound (5.6g) as an oil. b) 4-(3-Chloroprop-2-ynyl)phenylacetic acid methyl ester To a solution of 4-(3-Hydroxyprop-2-ynyl)phenylacetic acid methyl ester (5.5g, 0.027M) in tetrahydrofuran (110ml) and carbon tetrachloride (110ml) was added triphenylphosphine (7.81g, 1.1 molar equivalents). The reaction mixture was heated at 60°C for 3h. After cooling, the solid obtained was removed by filtration and the mother liquors were concentrated under vacuum. The residue was purified by chromatography on silica gel using 50% diethyl ether in hexane as eluent to give the required product (5.35g) as a colourless oil. c) 4-(3-Azidoprop-2-ynyl)phenylacetic acid methyl ester 4-(3-Chloroprop-2-ynyl)phenylacetic acid methyl ester (5.3g, 0.023M) was dissolved in dry dimethylformamide (30ml) with sodium azide (1.7g, 1.1 molar equivalents) and stirred at room temperature for 14h. The reaction mixture was diluted with water (200ml) and washed with dichloromethane (2 x 150ml). The combined organic layers were washed with water (2 x 100ml) and brine (1 x 100ml) then dried (Na 2 SO 4 ), filtered and concentrated in vacuo to give a residue which was purified by passage down a silica gel column, using as eluents 20% dichloromethane in hexane and finally neat dichloromethane, to give the required product (5.3g) as a colourless oil. d) 4-(3-(Tertiary-butyloxycarbonylamino)-prop-2-ynyl)phenylacetic acid methyl ester 4-(3-Azidoprop-2-ynyl)phenylacetic acid methyl ester (2.6g, 0.0113mol) was dissolved in methanol (60ml) in the presence of triethylamine (7.86ml, 5 molar equivalents) and propane 1,3-dithiol (5.67ml, 5 molar equivalents). After stirring at room temperature for 14h the reaction mixture was concentrated under vacuum and the residue was purified by silica gel chromatography, using initially neat dichloromethane then finally 5% methanol in dichloromethane. After evaporation of the solvents the residue obtained was dissolved in dichloromethane (100ml) and triethylamine (3.13ml, 2 molar equivalents) and ditertiary-butyldicarbonate (3.0g, 1.2 molar equivalents) were added. After stirring at room temperature for 14h the solvent was removed in vacuo and the oil obtained was purified by chromatography on silica gel using dichloromethane as eluent to give the required product as a viscous oil (1.95g). e) 4-(3-(Tertiary-butyloxycarbonylamino)prop-2-ynyl)phenylacetic acid 4-(3-Tertiarybutyloxycarbonylamino)-prop-2-ynylphenylacetic acid methyl ester (1.9g) was dissolved in 50% aqueous methanol (100ml) with sodium hydroxide (1g) and the solution stirred at room temperature for 14h. After this time the methanol was removed under vacuum and the aqueous residue was treated with 1N hydrochloric acid until a pH of 1 was obtained. The precipitate produced was extracted into ethyl acetate (2 x 200ml), the organic layer was dried (Na 2 SO 4 ), filtered and concentrated in vacuo to give the required product (1.7g) as a white solid. f) Trans-2-carboxy-4-(4-(3-aminoprop-2-ynyl)phenyl) methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the route outlined in Example 70b using 4-(3-(tertiarybutyloxycarbonylamino)prop-2-ynyl)phenylacetic acid in place of 4-(tertiarybutyloxy-carbonylamino)butanoic acid to give the title compound as colourless crystals, m.p. 162-164°C. EXAMPLE 83 Trans-2-methoxycarbonyl-4-(4-(3-aminoprop-2-ynyl)phenyl) methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given in Example 52 using trans -2-carboxy-4-(4-(3-aminoprop-2-ynyl)phenyl)methylcarbonylamino-5,7-dichloro-1,2,3,4- tetrahydroquinoline hydrochloride (Example 82) in place of trans -2-carboxy-4-(3-aminomethylphenyl)carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride to give the title compound as colourless crystals, m.p. 202°C dec. EXAMPLE 84 Trans-2-carboxy-4-(4-(3-aminopropyl)phenyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride a) 4-(3-(Tertiary-butyloxycarbonylamino)propyl)-phenylacetic acid methyl ester 4-(3-Azidoprop-2-ynyl)phenylacetic acid methyl ester (Example 82c) (2.6g, 0.0113m) was dissolved in ethyl acetate (100ml) with ditertiarybutyl dicarbonate (5.9g, 2.4 molar equivalents) and after the addition of 10% palladium on carbon catalyst (0.25g) the reaction mixture was shaken under a 50 p.s.i. pressure of hydrogen for 14h. The catalyst was removed by filtration and the organic solution was concentrated in vacuo to leave a residue which was purified by chromatography on silica gel, using 10% ethyl acetate in dichloromethane as eluent, to give the required product (2.07g) as an oil. b) 4-(3-(Tertiarybutyloxycarbonylamino)propyl)phenylacetic acid 4-(3-(Tertiarybutoxycarbonylamino)propyl)phenylacetic acid methyl ester (2.0g) was dissolved in 50% aqueous methanol (100ml) with sodium hydroxide (1g) and stirred at room temperature for 14h. The methanol was removed under vacuum and the residual aqueous solution was acidified to pH1 using 1N hydrochloric acid, and the resulting precipitate extracted into ethyl acetate (2 x 100ml). The combined organic extracts were dried (Na 2 SO 4 ), filtered and concentrated under vacuum to give the required product as a white solid (1.82g). c) Trans-2-carboxy-4-(4-(3-aminopropyl)phenyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the route outlined in Example 70b using 4-(3-(tertiarybutyloxycarbonylamino)-propyl)phenylacetic acid in place of 4-(tertiarybutyloxy-carbonylamino)butanoic acid to give the title compound as colourless crystals, m.p. 161-164°C. EXAMPLE 85 Trans-4-methoxycarbonyl-4-(4-(3-aminopropyl)phenyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method described in Example 52 using trans -2-carboxy-4-(4-(3-aminopropyl)phenyl)methylcarbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride in place of trans -2-carboxy-4-(3-aminomethyl-phenyl)carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride to give the title compound as colourless crystals, m.p. 140°C dec. EXAMPLE 86 Trans-2-carboxy-4(4-(4-aminobut-2-ynyl)phenyl) methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the methods given in Example 82a), b), c), d), and e) and Example 70b) using but-3-yn-l-ol in place of propynol (in Example 82a) to give the title compound as colourless crystals, m.p. 162°C dec. EXAMPLE 87 Trans-2-methoxycarbonyl-4(4-(4-aminobut-2-ynyl)phenyl) methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given in Example 52 using trans -2-carboxy-4-(4-(4-aminobut-2-ynyl)phenyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride in place of trans -2-carboxy-4-(3-aminomethylphenyl)carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride to give the title compound as colourless crystals, m.p. 162°C dec. EXAMPLE 88 Trans-2-carboxy-4(4-(4-aminobutyl)phenyl)methyl-carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the methods given in Examples 82a), b), c), 84a), b) and 70b) using but-3-yn-1-ol in place of propynol (in Example 82a) to give the title compound as colourless crystals, m.p. 110°C dec. EXAMPLE 89 Trans-2-methoxycarbonyl-4-(4-(4-aminobutyl)phenyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given in Example 52 using trans -2-carboxy-4-(4-(4-aminobutyl)phenyl)methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride in place of trans -2-carboxy-4-(3-aminomethylphenyl)carbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride to give the title compound as colourless crystals, m.p. 138-140°C. EXAMPLE 90 Trans-4-(3-aminomethylphenyl)methylcarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride Step a) 3-Bromomethylphenyl acetic acid methyl ester A solution of 3-tolylacetic acid (5g, 33mmol) and N-bromosuccinimide (5.9g, 33mmol) in carbon tetrachloride (100ml) was refluxed for 3 hours then cooled and filtered. The solvent was removed under vacuum to yield a crude product to which was added methanol (250ml) which had been saturated with hydrogen chloride (250ml) and this mixture was stirred at room temperature for 4 hours. The solvent was removed under vacuum and the crude residue was purified using flash chromatography (using ethyl acetate in hexane as eluent) to yield the title compound (7.3g) as a yellow oil. Step b) 3-Azidomethylphenyl acetic acid methyl ester To a solution of 3-bromomethylphenyl acetic acid methyl ester (7.3g, 30mmol) in N,N-dimethylformamide (100ml) was added sodium azide (2.53, 33mmol) and the solution was stirred at room temperature for 18 hours. The reaction mixture was poured into water (600ml), extracted into ethyl acetate (3 x 100ml) and the combined extracts were washed with water (2 x 100ml) and brine solution (2 x 100ml), dried (MgSO 4 ) and evaporated to give a crude product, which was purified by flash chromatography (using ethyl acetate in hexane as eluent) to give the title compound as an oil (4.2g). Step c) 3-(Tertiarybutyloxycarbonylaminomethyl)phenyl acid methyl ester This material was prepared using the method given for Example 84 step a) using 3-azidomethylphenyl acetic acid methyl ester in place of 4-(3-azidoprop-2-ynyl)phenylacetic acid methyl ester to give the title compound as an oil. Step d) 3-(Tertiarybutyloxycarbonylaminomethyl)phenyl acetic acid This material was prepared using the method given for Example 76 step b) using methyl 3-(tertiarybutyloxycarbonylaminomethyl)phenylacetate in place of methyl 4-(tertiarybutyloxocarbonylaminoethyl)phenylacetate to give the title compound as a colourless oil. Step e) Trans-4-(3-tertiary-butyloxycarbonylaminomethyl)phenylmethylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline This material was prepared using the method given for Example 7 step a) using 3-(tertiarybutyloxycarbonyl-aminomethyl)phenyl acetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p.162-163.4°C. Step f) Trans-4-(3-aminomethylphenyl)methyl-carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This material was prepared using the method given in Example 76 step d) using trans -4-(3-tertiary-butyloxy-carbonylaminomethyl) phenylmethylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline in place of trans -4-(4-tertiary-butyloxycarbonylaminoethylphenyl)-methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals, m.p. 163.7-165°C dec. EXAMPLE 91 Trans-4-(3-aminomethylphenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given in Example 77 using trans -4-(3-tertiary-butyloxycarbonylaminomethyl)phenylmethylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline (Example 90e) in place of trans -4(4-tertiary-butyloxycarbonylamino-ethylphenyl) methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline to give the title compound as a colourless solid; m.p. 161-162°C. EXAMPLE 92 Trans-4-(2-aminomethylphenyl)methylcarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride Step a) 2-(Azidomethyl)phenyl acetic acid This material was prepared using the method given for Example 90 steps a), b) and d) using 2-tolyacetic acid in place of 3-tolyacetic acid to give the title compound as a colourless oil. Step b) Trans-4-(2-azidomethylphenyl)methyl-carbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline This material was prepared using the method given for Example 7 step a) using 2-(azidomethyl)phenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 216-217°C. Step c) Trans-4-(2-tertiary-butyloxycarbonylamino-methyl) phenylmethylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline To a solution of trans -4-(2-azidomethylphenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline (0.3g, 0.67mmol) in ethyl acetate (30ml) was added ditertiary-butyldicarbonate (0.22g, 1.0mmol) and 10% palladium on carbon and this mixture was hydrogenated under 50 psi pressure for 18 hours. The mixture was filtered and the solvent was removed under vacuum to yield the crude product, which was purified by flash chromatography (using ethyl acetate in hexane as eluent) followed by recrystallisation from ethyl acetate/hexane to give the title compound, m.p. 224-225°C. Step d) Trans-4-(2-aminomethylphenyl)methyl-carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This material was prepared using the method given for Example 76 step d) using trans -4-(2-tertiarybutyloxy-carbonylaminomethyl) phenylmethylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline in place of trans -4-(4-tertiary-butyoxycarbonylaminoethylphenyl)- methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals, m.p. 182-185°C dec. EXAMPLE 93 Trans-4-(2-aminomethylphenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride This material was prepared by the method given in Example 77 using trans -4-(2-tertiary-butyloxycarbonylaminomethyl)phenylmethylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline in place of trans -4-(4-tertiary-butyloxycarbonylamino-ethylphenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline to give the title compound as a colourless solid, m.p. 169-172°C dec. EXAMPLE 94 Trans-4-(2-(4-aminomethylphenyl)ethyl)carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride Step a) 3-(4-Cyanophenyl)propenoic acid methyl ester To a solution of 4-cyanobenzaldehyde (10g) in toluene (100ml) was added methyl(triphenylphosphoranylidine)-acetate (30.6g) and the solution was heated to reflux for four hours, then cooled to room temperature. The solvent was removed under vacuum and the crude product was purified by flash chromatography (using ethyl acetate in hexane as eluent) to yield the title compound (11.5g). Step b) Methyl-4-tertiarybutyloxycarbonylaminomethylphenylproponate To a solution of 3-(4-cyanophenyl)propenoic acid methyl ester (10g) in ethanol (300ml) was added 1M hydrochloric acid (30ml) followed by 10% palladium on carbon (2g) and the resulting mixture was hydrogenated at room temperature under 50 psi for 18hr. The mixture was filtered and the solvent was removed under vacuum. To the crude residue was added dichloromethane (300ml) and ditertiarybutyldicarbonate (17.3g, 80.5mmol), followed by the dropwise addition of triethylamine (15ml, 204mmol) and the mixture was stirred at room temperature for 4 hours. The reaction mixture was washed with water (2 x 100ml), aqueous citric acid (2 x 100ml, 1M), saturated sodium bicarbonate solution (3 x 100ml) and brine solution (1 x 100ml), dried (MgSO 4 ) and evaporated. The crude residue was purified by flash chromatography (using ethyl acetate in hexane as eluent to give the title compound (2.5g). Step c) 4-Tertiarybutyloxycarbonylaminomethylphenyl propionic acid This material was prepared using the method given for Example 76 step b) using methyl-4-tertiary-butyloxocarbonylaminomethylphenylpropionate in place of methyl 4-(tertiarybutyloxycarbonylaminoethyl)-phenylacetate to give the title compound as colourless crystals, m.p. 140-141.5°C. Step d) Trans-4-(2-(4-tertiarybutyloxycarbonylaminomethylphenyl)ethyl)carbonylamino-5,7-dichloro-2-methoxycarbonyl- 1,2,3,4-tetrahydroquinoline This material was prepared using the method given for Example 7 step a) using 4-tertiarybutyloxycarbonyl-aminomethylphenylpropionic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 193-194°C. Step e) Trans-4-(2-(4-aminomethylphenvl)ethyl)-carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given in Example 76 step d) using trans -4-(2-(4-tertiary-butyloxycarbonylaminomethylphenyl) ethyl)carbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline in place of trans -4-(4-tertiarybutyloxycarbonylaminoethylphenyl)methylcarbonylamino-5,7-dichloro-2- methoxycarbonyl-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals, m.p. 156-159°C dec. EXAMPLE 95 Trans-4-(2-(4-aminomethylphenyl)ethyl)carbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given in Example 52 using trans -4-(2-(4-aminomethylphenyl)-ethylcarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride in place of trans -2-carboxy-5,7-dichloro-4-(3-aminomethylphenyl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride to give the title compound as colourless crystals, m.p. 172-173.2°C. EXAMPLE 96 Trans-4-(4-aminophenyl)methylcarbonylamino-5,7-dichloro-2-carboxy-1,2,3,4-tetrahydroquinoline hydrochloride Step a) Trans-4-(4-tertiarybutyloxycarbonylaminophenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline This material was prepared using the method given for Example 7 step a) using 4-tertiarybutyloxycarbonyl-aminophenylacetic acid in place of phenylacetic acid to give title compound as colourless crystals, m.p. 236-239°C. Step b) Trans-4-(4-aminophenyl)methylcarbonylamino-5,7-dichloro-2-carboxy-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given in Example 76 step d) using trans -4-(4-tertiarybutyloxy-carbonylaminophenyl) methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline in place of trans -4-(4-tertiarybutyloxycarbonylaminoethylphenyl)- methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals, m.p. 165-167°C. EXAMPLE 97 Trans-2-carboxy-5,7-dichloro-4-(1,2,3,4-tetrahydroisoquinol-3-yl)carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride Step a) Trans-5,7-dichloro-2-methoxycarbonyl-4-(3-(N-tertiarybutyloxycarbonyl)-1,2,3,4-tetrahydroisoquinoline) carbonylamino-1,2,3,4-tetrahydroquinoline This material was prepared using the method given for Example 7 step a) using 3-(N-tertiarybutyloxycarbonyl)-1,2,3,4-tetrahydroisoquinoline carboxylic acid in place of phenylacetic acid to give the title compound as colourless crystals; m.p. 244-246°C. Step b) Trans-2-carboxy-5,7-dichloro-4-(3-(N-tertiarybutyloxycarbonyl)1,2,3,4-tetrahydroisoquinoline)carbonylamino-1,2,3,4-tetrahydroquinoline This material was prepared using the method given for Example 76 step d) using trans -5,7-dichloro-2-methoxy-carbonyl-4-(3-N-tertiarybutyloxycarbonyl)-1,2,3,4-tetrahydroisoquinoline)carbonyamino-1,2,3,4-tetrahydro-quinoline in place of trans -4-(4-tertiarybutyloxycarbonyl-aminoethylphenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals; m.p. 212-214°C dec. EXAMPLE 98 Trans-4-(2-carboxyphenyl)carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline Step a) Trans-4-(2-carboxyphenyl)carbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline To a suspension of trans -4-amino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline (0.5g, 1.6mmol) in anhydrous tetrahydrofuran (50ml) under an atmosphere of nitrogen was added dry triethylamine (0.49ml, 3.5mmol) and the mixture stirred until dissolution was complete. To this solution was added phthalic anhydride (0.28g, 1.9mmol) and 4-dimethylaminopyridine (5mg) and the reaction mixture was stirred at room temperature for 3 hours. The mixture was then evaporated to dryness in vacuo and the residue was partitioned between ethyl acetate (100ml) and water (200ml). The organic layer was separated and washed successively with dilute hydrochloric acid (2 x 50ml, 1M), water (1 x 50ml) and brine (1 x 50ml), then dried (MgSO 4 ) and evaporated to give a solid which was recrystallised from ethyl acetate/ hexane to give the title compound as colourless crystals (0.45g), m.p. 241-243°C. Step b) Trans-4-(2-carboxyphenyl)carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline This material was prepared by the method given for Example 7 step b) using trans -4-(2-carboxyphenyl)-carbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline in place of trans -5,7-dichloro-2- methoxycarbonyl-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals, m.p. 195-197°C dec. EXAMPLE 99 Trans-2-carboxy-5,7-dichloro-4-(4-chloro-3-nitro-phenyl) methylcarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 7 using 4-chloro-3-nitrophenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 233-235°C. EXAMPLE 100 Trans-2-carboxy-5,7-dichloro-4-(4-hydroxy-3-nitro-phenyl) methylcarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 7 using 4-hydroxy-3-nitrophenylacetic acid in place of phenylacetic acid to give the title compound as yellow crystals, m.p. 245-247°C. EXAMPLE 101 Trans-2-carboxy-5,7-dichloro-4-(diphenylmethyl-carbonyl)amino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 7 using diphenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 238-239°C. EXAMPLE 102 Trans-2-carboxy-5,7-dichloro-4-(1-phenylethyl-carbonyl)amino-1,2,3,4-tetrahydroquinoline (isomer A) This compound was prepared by the method given in Example 7 using (±) 2-phenylpropionic acid in place of phenylacetic acid. The two diastereoisomers were separated by flash chromatography followed by recrystallisation as their methyl esters. The less polar isomer gave on treatment with lithium hydroxide, the title compound (isomer A) as colourless crystals, m.p. 210-212°C. EXAMPLE 103 Trans-2-carboxy-5,7-dichloro-4-(1-phenylethyl-carbonyl)amino-1,2,3,4-tetrahydroquinoline (isomer B) The more polar isomer from Example 102 on treatment with lithium hydroxide gave the title compound as colourless crystals, m.p. 248-249°C. EXAMPLE 104 Trans-2-carboxy-5,7-dichloro-4-(4-acetylphenyl-methylcarbonyl) amino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 7 using 4-acetylphenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 292-294°C dec. EXAMPLE 105 Trans-2-carboxy-5,7-dichloro-4-(phenyloxymethyl-carbonyl)amino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 7 using phenoxyacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 254-256°C. EXAMPLE 106 Trans-2-carboxy-5,7-dichloro-4-(4-ethylphenylmethylcarbonyl)amino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 7 using 4-ethylphenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 218-220°C. EXAMPLE 107 Trans-2-carboxy-5,7-dichloro-4-(4-hydroxyphenylmethyl-carbonyl) amino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 7 using 4-hydroxyphenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 259-261°C dec. EXAMPLE 108 Trans-2-carboxy-5,7-dichloro-4-(4-acetamidophenylmethyl carbonyl) amino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 7 using 4-acetylaminophenylacetic acid in place of phenylacetic acid to give the title compound as colourless crystals, m.p. 279-281°C. EXAMPLE 109 Trans-2-carboxy-5,7-dichloro-4-(1-naphthylamino) carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 8 using 1-naphthyl isocyanate in place of phenyl isocyanate to give the title compound as colourless crystals, m.p. 241-242°C. EXAMPLE 110 Trans-2-carboxy-5,7-dichloro-4-(cyclohexyl)-aminocarbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 8 using cyclohexylisocyanate in place of phenyl isocyanate to give the title compound as colourless crystals, m.p. 217-219°C. EXAMPLE 111 Trans-2-carboxy-5,7-dichloro-4-((N-methyl-N-4-methylphenyl)amino)carbonylamino-1,2,3,4-tetrahydroquinoline The material was prepared using the method given for Example 48 step b) and c) using N-methyl-N-4-methylphenyl aniline in place of N-methylaniline to give the title compound as colourless crystals, m.p. 210-212°C. EXAMPLE 112 Trans-2-carboxy-5,7-dichloro-4-(N,N-diphenylamino)carbonylamino-1,2,3,4-tetrahydroquinoline Step a) Trans-2-methoxycarboxyl-5,7-dichloro-4-(N,N-diphenylamino)carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 48 step b using N,N-diphenylamine in place of N-methylaniline to give the title compound as colourless crystals. Step b) Trans-2-carboxy-5,7-dichloro-4-(N,N-diphenylamino)carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 7 step b) using trans-2-methoxycarbonyl-5,7-dichloro-4-(N,N-diphenylamino)carbonylamino-1,2,3,4-tetrahydroquinoline in place of trans-5,7-dichloro-2-methoxycarbonyl-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals, m.p. 214-216°C. EXAMPLE 113 Trans-2-carboxy-5,7-dichloro-4-(4-ethylphenyl)amino-carbonylamino-1,2,3,4-tetrahydroquinoline This compound was prepared by the methods given in Example 48 steps a-c) using 4-ethylaniline in place of 4-iodoaniline to give the title compound as colourless crystals, m.p. 195-197°C. EXAMPLE 114 Trans-2-carboxy-5,7-dichloro-4-((N-ethyl-N-phenyl)amino) carbonylamino-1,2,3,4-tetrahydroquinoline This material was prepared using the method given in Example 48 step b and c) using N-ethylaniline in place of N-methylaniline to give the title compound as colourless crystals, m.p. 227-229°C. EXAMPLE 115 Trans-2-[(tertiary-butylcarbonyloxy)methyloxycarbonyl]-5,7-dichloro-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline To a solution of trans -2-carboxy-5,7-dichloro-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline (0.06g, 0.16mmol, Example 4) in tetrahydrofuran (5ml) was added triethylamine (0.027ml, 0.19mmol) followed by a solution of iodomethylpivalate (0.06g, 0.24mmol) in tetrahydrofuran (2ml). This mixture was stirred at room temperature for 4 hours. The solvent was removed under vacuum and the residue obtained was purified by flash chromatography (using ethyl acetate in hexane as eluent) to give the title compound (0.044g), m.p. 162.4-163°C. EXAMPLE 116 Trans-5,7-dichloro-2-[(N-methylaminocarbonylmethyl)oxycarbonyl]-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline To a solution of trans -2-carboxy-5,7-dichloro-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline (0.05g, 0.13mmol, Example 4) in tetrahydroquinoline (5ml) was added triethylamine (0.055ml, 0.4mmol), 1-hydroxy-N-methylacetamide (0.018g, 0.2mmol), 4-dimethylaminopyridine (0.019g, 0.16mmol) and 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (0.03g, 0.16mmol). This mixture was stirred at room temperature for 18 hours. The solvent was removed under vacuum and the residue was partitioned between ethyl acetate (50ml) and citric acid solution (1M, 100ml). The organic layer was separated and washed successively with citric acid solution (1M, 1 x 75ml), saturated sodium bicarbonate solution (2 x 75ml), saturated brine (1 x 75ml) then dried (MgSO 4 ) and evaporated and the residue purified by flash chromatography (using ethyl acetate in hexane as eluent) to give the title compound (0.037g), m.p. 229-231°C. EXAMPLE 117 Trans-5,7-dichloro-2-[(N,N-dimethylamino)ethylaminocarbonylmethyl)oxycarbonyl]-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride To a solution of trans -2-carboxy-5,7-dichloro-4 phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline (0.1g, 0.26mmol, Example 4) in tetrahydrofuran (20ml) was added 1,1-carbonyldiimidazole (0.064g, 0.4mmol) and this mixture heated to reflux under an atmosphere of nitrogen for 3 hours. The reaction mixture was cooled to -78°C and a preformed solution of the lithium salt of 1-hydroxy-N,N-dimethylaminoethylacetamide [formed from addition of n-butylithium (0.63ml of 1.6M solution in hexane) to a solution of 1-hydroxy-N,N-dimethylaminoethylacetamide (0.170g, 1.1mmol) in tetrahydrofuran (10ml) at -78°C and warmed to room temperature then recooled back to -78°C], was added and after stirring for 3 minutes acetic acid (0.3ml, 5mmol) was added and the mixture left to warm to room temperature. The solvent was removed under vacuum and the residue was partitioned between ethyl acetate (50ml) and saturated sodium bicarbonate (100ml). The organic layer was separated and washed successively with saturated sodium bicarbonate (1 x 75ml), saturated brine (1 x 75ml), then dried (MgSO 4 ) and evaporated. To the residue was added hydrogen chloride in ethyl acetate (1ml, 5M), this solution was extracted with water (2 x 50ml) and the aqueous layer freeze dried to yield the title compound as a white solid (0.036g). EXAMPLE 118 Trans-5,7-dichloro-2(2-N,N-diethylaminoethyl)oxycarbonyl-4-phenylmethyl-carbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride Step a) N,N-diethylethanolamine lithium salt To a solution of N,N-diethylethanolamine (0.265ml, 2.0mmol) in anhydrous tetrahydrofuran (10ml) cooled to -78°C under an atmosphere of nitrogen was slowly added a 1.6M solution of n-butyllithium in hexane (1.25ml, 2.0mmol). The mixture was then allowed to warm to room temperature and was used as such for step b). Step b) Trans-5,7-dichloro-2(2-N,N-diethylaminoethyl)oxycarbonyl-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride To a solution of trans -2-carboxy-5,7-dichloro-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline (0.100g, 0.264mmol) in anhydrous tetrahydrofuran (20ml) was added carbonyldlimidazole (0.065g, 0.40mmol) and the resulting mixture was heated at reflux under an atmosphere of nitrogen for 3h. The reaction was then cooled to -78°C and a solution of N,N-diethylethanolamine lithium salt in tetrahydrofuran (from step a), 4.60ml, 0.80mmol) was added slowly. The resulting mixture was stirred at -78°C for 5 mins then quenched with glacial acetic acid (0.1ml), allowed to warm to room temperature and concentrated in vacuo . The residue was suspended in ethyl acetate (50ml), washed with saturated sodium bicarbonate (2 x 20ml), saturated brine (1 x 20ml), dried (MgSO 4 ) and evaporated under vacuum to give a solid which was purified by flash chromatography on silica gel, using 5% methanol in dichloromethane as eluent. To a solution of the purified material in ethyl acetate (5ml) was added a saturated solution of hydrogen chloride in ethyl acetate (1ml) and the resulting mixture was stirred at room temperature for 5 min. The solvent was removed under vacuum to give the crude hydrochloride salt as an oil which was dissolved in water (10ml), filtered and freeze dried to give the title compound as a colourless foam (0.072g). EXAMPLE 119 Trans-5,7-dichloro-2-(3-N,N-dimethylaminopropyl) oxycarbonyl-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline hydrochloride This material was prepared in the same way as Example 118 but using 3-dimethylamino-1-propanol in place of N,N-diethylethanolamine (step a) to give the title compound as a colourless foam. EXAMPLE 120 Trans 2-(2-(N,N-dimethylamino)ethyl)aminocarbonyl-4-phenylmethylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline Trans 5,7-dichloro-2-methoxycarbonyl-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline (Example 7a) (0.3g) was dissolved in N,N-dimethylethylene-diamine (30ml) and allowed to stand at room temperature for 6h. After this time the reaction mixture was filtered and the solvent was removed under vacuum. The residue was dissolved in ethyl acetate (100ml) and washed with water (100ml) then brine (100ml). The organic solution was dried (MgSO 4 ), filtered and concentrated in vacuo to give a solid which was triturated with diethyl ether and collected by filtration to give the title compound (0.19g) as a colourless solid, m.p. 158-159°C. EXAMPLE 121 Trans-2-(2-(N,N-dimethylamino)ethyl)aminocarbonyl-4-phenylaminocarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline This compound was prepared by the route outlined in Example 120 using trans 5,7-dichloro-2-methoxycarbonyl-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline (example 8a) in place of trans-5,7-dichloro- 2-4-methoxycarbonylphenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline to give the title compound as colourless crystals m.p. 223-224°C. EXAMPLE 122 Trans-4-(4-aminomethylphenyl)methylcarbonylamino-5,7-dichloro-2-(N-methylaminocarbonylmethyl)oxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride Step a) Trans-4-(4-tertiary-butyloxycarbonylaminophenyl)methylcarbonylamino-5,7-dichloro-2-(N-methylaminocarbonylmethyl)oxycarbonyl-1,2,3,4-tetrahydroquinoline This compound was prepared by the method given in Example 116 using trans -4-(4-tertiary-butyloxycarbonylaminophenyl)methylcarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline (Example 74) in place of trans -2-carboxy-5,7-dichloro-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline to give the title compound. Step b) Trans-4-(4-aminomethylphenyl)methylcarbonylamino-5,7-dichloro-2-(N-methylaminocarbonylmethyl)oxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the method given in Example 77 using trans -4-(4-tertiary-butyloxycarbonylaminophenyl)methylcarbonylamino-5,7-dichloro-2-(N-methylaminocarbonylmethyl)oxycarbonyl-1,2,3,4-tetrahydroquinoline in place of trans -4-(4-tertiary-butyloxycarbonylaminoethylphenyl)methylcarbonylamino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline to give the title compound, m.p. 195-197°C dec. EXAMPLE 123 Trans-4-(4-aminomethylphenyl)methylcarbonylamino-5,7-dichloro-2-hexyloxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride This compound was prepared by the methods given for Example 116 followed by Example 77 using n-hexanol in place of 1-hydroxy-N-methylacetamide to give the title compound as colourless solid, m.p. 249-251°C. EXAMPLE 124 Tablet Preparation Tablets containing 1.0, 2.0, 25.0, 26.0, 50.0 and 100.0mg, respectively, of: Trans-2-carboxy-5,7-dichloro-4-phenylmethylcarbonylamino-1,2,3,4-tetrahydroquinoline Trans-2-carboxy-5,7-dichloro-4-benzoylamino-1,2,3,4-tetrahydroquinoline Trans-2-carboxy-5,7-dichloro-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline Trans-2-methoxycarbonyl-4-(4-aminomethylphenyl) methylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline hydrochloride TABLE FOR DOSES CONTAINING FROM 1-25MG OF THE ACTIVE COMPOUND Amount-mg. Active Compound 1.0 2.0 25.0 Microcrystalline cellulose 49.25 48.75 37.25 Modified food corn starch 49.25 48.75 37.25 Magnesium stearate 0.50 0.50 0.50 TABLE FOR DOSES CONTAINING FROM 26-100MG OF THE ACTIVE COMPOUND Amount-mg Active Compound 26.0 50.0 100.0 Microcrystalline cellulose 52.0 100.0 200.0 Modified food corn starch 2.21 4.25 8.5 Magnesium stearate 0.39 0.75 1.5 All of the active compound, cellulose, and a portion of the corn starch are mixed and granulated to 10% corn starch paste. The resulting granulation is sieved, dried and blended with the remainder of the corn starch and the magnesium stearate. The resulting granulation is then compressed into tablets containing 1.0mg, 2.0mg, 25.0mg, 26.0mg, 50.0mg, and 100mg of active ingredient per tablet.

Claims: A compound of formula IIC or a salt thereof: wherein R 1 represents a carboxy group or a group which is convertible thereto in vivo ; R 2 represents hydrogen; R 5 , R 6 , R 7 and R 8 independently represent hydrogen, halogen, cyano, trifluoromethyl, nitro, hydroxy, amino, carboxy, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 alkylthio or C 1-6 alkoxycarbonyl; and R a and R b independently represent hydrogen; or C 1-6 alkyl, C 2-6 alkenyl, C 3-7 cycloalkyl, C 3-7 cycloalkyl(C 1-6 )alkyl, aryl selected from phenyl, naphthyl and fluorenyl, aryl(C 1-6 )alkyl, C 3-7 heterocycloalkyl, C 3-7 heterocycloalkyl(C 1-6 )alkyl, heteroaryl selected from pyridyl, quinolyl, isoquinolyl, pyridazinyl, pyrimidinyl, pyrazinyl, pyranyl, furyl, benzofuryl, thienyl, benzthienyl, indolinyl, imidazolyl, oxadiazolyl, thiadiazolyl and tetrazolyl, or heteroaryl(C 1-6 )alkyl, any of which groups may be optionally substituted by one or more groups selected from methyl, ethyl, phenyl, chloro, aminomethyl, aminoethyl, aminopropyl, aminobutyl, methylaminomethyl, dimethylaminomethyl, aminopropynyl, aminobutynyl, hydroxy, methoxy, phenoxy, nitro, cyano, carboxy, acetyl, amino and acetylamino. A compound as claimed in claim 1 wherein R a is hydrogen and R b represents phenyl or benzyl, optionally substituted by an aminomethyl or aminoethyl group. A compound of formula IID or a salt thereof: wherein R 1 , R 2 , R 5 , R 6 , R 7 and R 8 are as defined in claim 1; R a and R i independently represent hydrogen, C 1-6 alkyl or aryl selected from phenyl, naphthyl and fluorenyl; R b represents C 3-7 cycloalkyl, aryl selected from phenyl naphthyl and fluoroenyl, or aryl(C 1-6 )alkyl, any of which groups may be optionally substituted by one or more groups selected from methyl, ethyl, chloro, iodo, methoxy and nitro; and X represents oxygen or sulphur. A compound as claimed in claim 3 wherein R a and R i independently represent hydrogen, methyl, ethyl or phenyl; and R b represents cyclohexyl, phenyl, naphthyl or benzyl. A compound as claimed in claim 4 wherein R a and R i both represent hydrogen; and X represents oxygen. A compound as claimed in any one of the preceding claims wherein R 8 represents hydrogen, and R 5 , R 6 and R 7 independently represent hydrogen, halogen or C 1-6 alkyl. A compound as claimed in claim 1 selected from: 4-benzoylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-acetylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-cyclohexylcarbonylamino-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(4-chlorophenylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-pyridylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-[2-(2-aminophenethyl)]carbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-n-propylcarbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-methoxyphenylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-methoxybenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-methylbenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(α-methoxybenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-nitrobenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 4-(4'-biphenylcarbonylamino)-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-isopropylcarbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(2-chlorophenylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(1-naphthylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-naphthylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-furylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-methylphenylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-phenethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-phenylethenylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-thienylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(3-chlorophenylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-phenylpropylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(9-fluorenylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-cyclohexylmethylcarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(2-chlorobenzylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(3-chlorobenzylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(4-chlorobenzylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-methylbenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-methoxybenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-nitrobenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(3-cyanophenylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2,3-dihydroindol-1-ylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-[2-(carboxyethyl)carbonylamino]-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[3-(aminomethyl)phenylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[3-(aminomethyl)phenylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)phenylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)phenylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(2-aminoethyl)phenylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(2-aminoethyl)phenylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-methylbenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-nitrobenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-methoxybenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(1-naphthylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-naphthylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-thienylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2,6-dichlorobenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 4-(3-aminopropyl)carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-(2-aminoethyl)carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-(4-aminobutyl)carbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-piperidylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(2-aminoethyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(2-aminoethyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-[4-(N-methylaminomethyl)-benzylcarbonylamino]-1,2,3,4-tetrahydroquinoline; 5,7-dichloro-2-methoxycarbonyl-4-[4-(N-methylaminomethyl)benzylcarbonylamino]-1,2,3,4-tetrahydroquinoline; 5,7-dichloro-4-[4-(N,N-dimethylaminomethyl)benzylcarbonylamino]-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-[4-(N,N-dimethylaminomethyl)benzylcarbonylamino]-1,2,3,4-tetrahydroquinoline; 4-[4-(3-aminoprop-2-ynyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(3-aminoprop-2-ynyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(3-aminopropyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(3-aminopropyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(4-aminobut-2-ynyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(4-aminobut-2-ynyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(4-aminobutyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[4-(4-aminobutyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[3-(aminomethyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[3-(aminomethyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[2-(aminomethyl)benzylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[2-(aminomethyl)benzylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[2-(4-(aminomethyl)phenyl)ethylcarbonylamino]-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-[2-(4-(aminomethyl)phenyl)ethylcarbonylamino]-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-(4-aminobenzylcarbonylamino)-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(2-carboxyphenylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(4-chloro-3-nitrobenzylcarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-hydroxy-3-nitrobenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(diphenylmethylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(1-phenylethyl)carbonylamino-1,2,3,4-tetrahydroquinoline; 4-(4-acetylbenzylcarbonylamino)-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-phenoxymethylcarbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-ethylbenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-hydroxybenzylcarbonylamino)-1,2,3,4-tetrahydroquinoline; 4-(4-acetamidobenzylcarbonylamino)-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-2-(t-butylcarbonyloxy)methoxycarbonyl-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-5,7-dichloro-2-(methylaminocarbonyl)methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-5,7-dichloro-2-[2-(N,N-dimethylamino)ethylaminocarbonyl]methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-5,7-dichloro-2-[2-(N,N-dimethylamino)ethoxycarbonyl]-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-5,7-dichloro-2-[3-(N,N-dimethylamino)propoxycarbonyl]-1,2,3,4-tetrahydroquinoline; 4-benzylcarbonylamino-5,7-dichloro-2-[2-(N,N-dimethylamino)ethylaminocarbonyl]-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)benzylcarbonylamino]-5,7-dichloro-2-(methylaminocarbonyl)methoxycarbonyl-1,2,3,4-tetrahydroquinoline; 4-[4-(aminomethyl)benzylcarbonylamino]-5,7-dichloro-2-hexyloxycarbonyl-1,2,3,4-tetrahydroquinoline; and salts thereof; wherein the relative orientation of the substituents at the 2- and 4-positions of the tetrahydroquinoline ring system is trans . A compound as claimed in claim 3 selected from: 2-carboxy-5,7-dichloro-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline; 4-benzylaminocarbonylamino-2-carboxy-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-nitrophenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-methoxyphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(2-methylphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(2-chlorophenylaminocarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(4-chlorophenylaminocarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-methylphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-methoxyphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-nitrophenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-iodophenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-[phenylaminocarbonyl(N-methyl)amino]-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-[(N-methyl-N-phenyl)aminocarbonylamino]-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-phenylaminothiocarbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-methoxyphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-methylphenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-(3-chlorophenylaminocarbonylamino)-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(3-nitrophenylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(1-naphthylaminocarbonylamino)-1,2,3,4-tetrahydroquinoline; 2-carboxy-4-cyclohexylaminocarbonylamino-5,7-dichloro-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-[N-methyl-N-(4-methylphenyl)amino]carbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(N,N-diphenylamino)carbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(4-ethylphenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline; 2-carboxy-5,7-dichloro-4-(N-ethyl-N-phenyl)aminocarbonylamino-1,2,3,4-tetrahydroquinoline; 5,7-dichloro-2-[2-(N,N-dimethylamino)ethylaminocarbonyl]-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline; and salts thereof; wherein the relative orientation of the substituents at the 2- and 4-positions of the tetrahydroquinoline ring system is trans . Trans -2-carboxy-5,7-dichloro-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline, or a pharmaceutically acceptable salt thereof. A pharmaceutical composition comprising a compound as claimed in any one of the preceding claims in association with a pharmaceutically acceptable carrier. The use of a compound as claimed in any one of claims 1 to 9 for the manufacture of a medicament for the treatment and/or prevention of neurodegenerative disorders. A process for the preparation of a compound as claimed in any one of claims 1 to 9, which process comprises: (A) reduction of a quinoline derivative of formula IV: wherein R 1 , R 2 , R 5 , R 6 , R 7 and R 8 are as defined in claim 1, and R 4 represents -NR a COR b or -NR i CXNR a R b as defined in claims 1 and 3 respectively; or (B) reaction of a compound of formula A-COR b with a compound of formula V: wherein the relative orientation of the R 1 and -NHR a substituents is trans ; R 1 , R 2 , R 5 , R 6 , R 7 , R 8 , R a and R b are as defined in claim 1; and A represents a leaving group; or (C) reaction of a compound of formula X, or a protected derivative thereof, with a compound of formula XI, or a protected derivative thereof: wherein R 1 , R 2 and R 5 to R 8 are as defined in claim 1, and R 4 is as defined above; followed, where necessary, by removal of the protecting groups.

Inventors: BAKER RAYMOND DR, CARLING WILLIAM R DR, LEESON PAUL D DR, SMITH JULIAN D, BAKER, RAYMOND, DR., CARLING, WILLIAM R., DR., LEESON, PAUL D., DR., SMITH, JULIAN D.
Applicants: MERCK SHARP & DOHME, MERCK SHARP & DOHME LTD.
Application year: 1990
Main classification: C07D215
IPC codes: C07D215, C07D405, A61P25, C07D491, C07D409, C07D487, A61K31, C07D401, C07D413