SOMATOSTATIN AGONISTS AND ANTAGONISTS

Abstract: The present invention relates to somatostatin ligands (Ia) or (Ib) which are useful for treating medical disorders related to binding to human somatostatin receptor subtypes, wherein X is =S, =O, =NH, =NCOPh or =N(CN), A is aryl optionally substituted with halogen, amino, hydroxy, nitro, C1-6-alkyl, C1-6-alkoxy or aryl, B is aryl optionally substituted with halogen, amino, hydroxy, C1-6-alkyl, C1-6-alkoxy or aryl, D is aryl, amino, optionally substituted with halogen, amino, hydroxy, C1-6-alkyl, C1-6-alkoxy or aryl, or a pharmaceutically acceptable salt thereof.

Description: SOMATOSTATIN AGONISTS AND ANTAGONISTS FIELD OF INVENTION The present invention relates to compounds, compositions containing them, and their use for treating medical disorders related to binding to human somatostatin receptor subtypes. BACKGROUND OF THE INVENTION Somatostatin (somatotropin release inhibiting factor; SRIF), a tetradecapeptide origi¬ nally isolated from ovine hypothalamus on the basis of its ability to inhibit growth hormone release from anterior pituitary cells (Brazeau, P. et al., Science 179, 77-79, 1973) has been shown to be present in several other tissues (for a review see Reichlin, S., N. Engl. J. Med. 309, 1495-1501 , 1983 and ibid, 1556-1563). Somato- statin appears to have widespread functions as a modulator of neuronal activity as well as of endocrine and exocrine secretion. Inhibitory effects of this peptide on the release of a variety of hormones such as growth hormone, prolactin, glucagon, insu¬ lin, gastrin and thyroid stimulating hormones have been described (for a review see Wass, J.A.H., in Endocrinology, ed. deGrott, LJ., vol 1, 152-166, 1989). Somato- statin is best regarded as belonging to a phylogenetically ancient, multigene family of peptides with two important bioactive products, namely SRIF-14 (SRIF) and SRIF-28, a congener of SRIF extended at the N-terminus. The regulatory functions of SRIF are mediated by specific membrane receptors. Cur- rently, only agonists are available to study the pharmacology of SRIF receptors. High-affinity saturable binding sites have been demonstrated in a number of tissues, e.g. pituitary gland, brain and pancreas. Within the last few years the cloning and isolation of five somatostatin receptor genes has been reported for various species (human, rat, mouse and bovine). Structural analysis of the encoded proteins re¬ vealed that the somatostatin receptor proteins (SST1-SST5) represent a distinct re¬ ceptor subfamily (named the A5 subfamily) belonging to the superfamily of G protein- coupled receptors with seven putative membrane spanning regions. Recent work on the development of nonpeptide structures substituting the peptide backbone of small cyclic peptides with a β-D-glucose scaffold (Hirschmann, R. er al., J.Am. Chem. Soc. 115, 12550-12568, 1993) or xylofuranose scaffold (Papageorgiou, C. et al., Bioorg. Med. Chem. Lett. 2, 135-140, 1992) or a benzodiazepinone scaffold (Papageorgiou, C. & Borer, X., Bioorg. Med. Chem.Lett. 6, 267-272, 1996) demon¬ strated low somatostatin receptor affinity. However, these structures are nonselective displaying higher affinities for both β2-adrenergic receptors and tachykinin receptors. Thus, there have been no reports in the literature on the successful development of a selective, competitive somatostatin receptor ligand of nonpeptide origin. SUMMARY OF THE INVENTION Accordingly, the present invention relates to a compound of general formula la or lb B la or .R 2 -(CH 2 ) n R B lb wherein m is 2, 3, 4, 5 or 6, preferably 2, 3, 4 or 5, n is 1 , 2 or 3, preferably 1 , p is 1 , 2, 3, 4, 5 or 6, preferably 2, 3 or 4, Rl and R2 are independently hydrogen or C-j_g-alkyl optionally substituted with halogen, amino, hydroxy, alkoxy or aryl, X is =S, =0, =NH, =NCOPh or =N(CN), A is aryl, preferably pyridinyl, quinolinyl, isoquinolinyl, pyrimidinyl, pyrazinyl, pyridazi- nyl or triazinyl optionally substituted with one or more, preferably one or two halogen, amino, hydroxy, nitro, Cι_6-alkyl , C-μβ-alkoxy or aryl, B is aryl, preferably phenyl, naphthyl, quinolinyl, isoquinolinyl, indolyl, thienyl, furanyl or pyridinyl optionally substituted with one or more, preferably one or two halogen, amino, hydroxy, C-|_6-alkyl, C-μβ-alkoxy or aryl, D is aryl, preferably imidazolyl, pyridinyl, pyrimidinyl, piperazinyl, triazolyl, tetrazolyl, thiadiazolyl, isoxazolyl or oxadiazolyl optionally substituted with one or more, pref¬ erably one or two halogen, amino, hydroxy, C-|_6-alkyl, Cι_6-alkoxy or aryl; or amino, piperidinyl, pyrrolidinyl or morpholinyl, optionally substituted with C-j.β-alkyl or aryl, and the pharmaceutically acceptable salts thereof. The compounds of formula la or lb comprise any optical isomers thereof, in the form of separated, pure or partially purified optical isomers or racemic mixtures thereof. In one embodiment of the compound of formula la, X is =S, =NH, =NCOPh, or =N- CN, preferably =S, =NH or =NCOPh. In another embodiment of the compound of formula la or lb, A is pyridinyl, e.g. pyridin-2-yl, pyridin-3-yl, quinolinyl, e.g. quinol-2-yl, isoquinolinyl, pyrimidinyl, e.g. pyrimidin-2-yl, pyrazinyl, pyridazinyl, e.g. pyridazin-2-yl, or triazinyl optionally substi¬ tuted with one halogen, e.g. 5-bromo, amino, hydroxy, nitro, e.g. 5-nitro, C-j.ρ-alkyl , C-|_6-alkoxy or aryl. Preferably A is pyridinyl or quinolinyl optionally substituted with halogen, amino, hy¬ droxy, nitro, Cι_6-alkyl, C<|_6-alkoxy or aryl, preferably pyridinyl, pyridinyl substituted with bromo or nitro, or quinolinyl. In a further embodiment of the compound of formula la or lb, B is phenyl, naphthyl, e.g. naphth-1-yl or naphth-2-yl , quinolinyl, isoquinolinyl, indolyl, thienyl, furanyl or pyridinyl optionally substituted with one or two halogen, e.g. 4-bromo or 3,4-dichloro, amino, hydroxy, C-μβ-alkyl, C-|_6-alkoxy or aryl. Preferably B is phenyl or naphthyl optionally substituted with halogen, amino, hy- droxy, nitro, Ci_g-alkyl, C-μβ-alkoxy or aryl, preferably phenyl substituted with bromo or two chloro, or naphthyl, e.g naphth-1-yl. In a still further embodiment of the compound of formula la or lb, D is amino, imida¬ zolyl, e.g. 1 H-imidazol-4-yl or imidazol-1-yl pyridinyl, e.g. pyridin-2-yl, pyrimidinyl, piperidinyl, pyrrolidinyl, e.g. pyrrolidin-1-yl, piperazinyl, pyridinylamino, pyrimidiny- lamino, piperidinylamino, pyrrolidinylamino, piperazinylamino, morpholinyl, e.g. mor- pholin-4-yl, triazolyl, tetrazolyl, thiadiazolyl, isoxazolyl or oxadiazolyl optionally sub¬ stituted with one or two halogen, amino, hydroxy, Cι_6-alkyl, C-)_6-alkoxy or aryl. Preferably D is imidazolyl, morpholinyl, pyrrolidinyl, amino or pyridinylamino option¬ ally substituted with one or two halogen, amino, hydroxy, C^.g-alkyl, C-j^-alkoxy or aryl, preferably imidazolyl, morpholinyl, dimethylamino, pyrrolidinyl, pyridinylamino, amino or pyridinyl. In a further embodiment of the compound of formula la or lb, R<| and R2 are inde¬ pendently of each other hydrogen or C<|_6-alkyl, preferably hydrogen or methyl. Whenever a heteroaryl or aryl is substituted such substitution(s) may be in any pos¬ sible ring position, which may be recognized by the skilled person without any undue burden. In another aspect the invention relates to somatostatin receptor ligands of nonpeptide origin which have affinity to the somatostatin receptor proteins selected from SST1 , SST2, SST3, SST4 and SST5. In an embodiment of the somatostatin receptor ligands of nonpeptide origin, said ligands have selective affinity to one or two of the somatostatin receptor proteins se¬ lected from SST1 , SST2, SST3, SST4 and SST5. In a further embodiment of the somatostatin receptor ligands of nonpeptide origin, said ligands have selective affinity to SST1. In a still further embodiment of the somatostatin receptor ligands of nonpeptide ori¬ gin, said ligands have selective affinity to SST2. In a further embodiment of the somatostatin receptor ligands of nonpeptide origin, said ligands have selective affinity to SST3. In a still further embodiment of the somatostatin receptor ligands of nonpeptide ori¬ gin, said ligands have selective affinity to SST4. In a further embodiment of the somatostatin receptor ligands of nonpeptide origin, said ligands have selective affinity to SST5. In a still further embodiment of the somatostatin receptor ligands of nonpeptide ori¬ gin, said ligands have selective affinity to SST1 and SST2, SST2 and SST3, SST3 and SST4, SST4 and SST5, SST1 and SST3, SST2 and SST4 or SST3 and SST5. DETAILED DESCRIPTION OF THE INVENTION Examples of specific compounds of the present invention are 1 -(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)propyl)-3-(3-(1 H-imidazol- 4-yl)propyl)thiourea 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(1 H-imidazol-4- yl)propyl)thiourea 1-(4-Aminobutyl)-3-(3-(N-(5-bromopyridin-2-yl)-N-(3,4- dichlorobenzyl)amino)propyl)thiourea 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)- amino)propyl)-3-(3-(N-(pyridin- 2-yl)amino)propyl)thiourea 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(N,N- dimethylamino)propyl)thiourea 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(morpholin-4- yl)propyl)thiourea 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(imidazol-1- yl)propyl)thiourea 1-(4-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)butyl)-3-(3-(imidazol-1- yl)propyl)thiourea 1 -(4-(N-(3,4-Dichlorobenzyl)-N-(pyridin-2-yl)amino)butyl)-3-(3-(imidazol-1 yl)propyl)thiourea 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)propyl)-3-(3-(imidazol-1- yl)propyl)thiourea 1-(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)butyl)-3-(3-(imidazol-1- yl)propyl)thiourea 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(4-(N-(pyridin-2- yl)amino)propyl)thiourea 1-(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)butyl)-3-(3-(1 H-imidazol- 4-yl)propyl)thiourea 1-(5-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)pentyl)-3-(3-(1H-imidazol- -yl)propyl)thiourea 1-(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)butyl)-3-(2-(1H-imidazol- 4-yl)ethyl)thiourea -(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(2-(1 H-imidazol- -yl)ethyl)thiourea -(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(3-(1 H-imidazol- -yl)propyl)thiourea 1-(3-(N-(5-Bromopyridin-2-yl)-N-((naphth-1-yl)methyl)-amino)propyl)-3-(3-(1 H- imidazol-4-yl)propyl)thiourea 1-(4-Aminobutyl)-3-(3-(N-(5-bromopyridin-2-yl)-N-((naphth-1- yl)methyl)amino)propyl)thiourea 1 -(2-(N-(5-Nitropyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) ethyl)-3-(3-(1 H- imidazol-4-yl)propyl)thiourea 1-(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) ethyl)-3-(3- (pyrrolidin-1-yl)propyl)thiourea 1-(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) ethyl)-3-(3- dimethylaminopropyl)thiourea 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) propyl)-3-(4-(N- (pyridin-2-yl)amino)propyl)thiourea 1-(4-Aminobutyl)-3-[3-[N-(5-bromopyrid-2-yl)]-[N-(3,4- dichlorobenzyl)]aminopropyl]thiourea 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) propyl)-3-(3- (pyrrolidin-1-yl)propyl)thiourea 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) propyl)-3-(2-(pyrid- 2-yl)ethyl)thiourea 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[2-(1 H-imidazol-4- yl)propyl]guanidine 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[2-(1H-imidazol-4- yl)ethyl]guanidine 1 -[3-[N-(4-Bromobenzyl)-N-(pyridazin-2-yl)amino]propyl]-3-[3-( 1 H-imidazol-4- yl)propyl]guanidine 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-3-yl)amino]propyl]-3-[3-(1 H-imidazol-4- yl)ethyl]guanidine 1 -[3-[N-(4-Bromobenzyl)-N-(pyrimidin-2-yl)amino]propyl]- 3-[2-(1 H-imidazol-4- yl)ethyl]guanidine 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[3-(imidazol-1- yl)propyl]guanidine 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[3-[N-(pyridin-2- yl)amino]propyl]guanidine 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[2-(pyridin-2- yl)ethyl]guanidine 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[3-(morpholin-4- yl)propyl]guanidine 1-Methyl-1-[3-(N,N-dimethylamino)propyl]-3-[3-[N-(4-bromobenzyl)-N-(pyridin-2- yl)amino]propyl]guanidine 1-[3-[N-(4-bromobenzyl)-N-(quinol-2-yl)amino]-propyl]-2-Benzoyl-3-[3-(1H-imidazol-4- yl)propyl]guanidine N1-[3-(lmidazol-4(5)-yl)propyl]-N2-[3-[N-(4-bromobenzyl)-N-(pyridin-2-yl)- amino]propyl]-S-methylisothiourea The compounds of the invention can be employed to mediate the biological effects of somatostatin agonists or antagonists. It is predicted that compounds of formula la or lb exhibit an improved bioavalability because they contain no amide bonds suscepti¬ ble to cleavage by proteolytic enzymes. The increased resistance to proteolytic deg¬ radation combined with the reduced size of the compounds of the invention in com¬ parison with known somatostatin agonists and antagonists is expected to possess beneficial properties such as increased peroral absorption, increased biological half- life, lack of immunogenicity, and the ability to cross the blood-brain barrier compared to that of the compounds suggested in the prior literature. Compounds of formula la or lb are believed to be useful for the development of pharmaceutical, therapeutic, and diagnostic techniques. Accordingly, the invention also provides methods for producing a prophylactic or therapeutic responce in a mammal by administering to the mammal a pharmaceutically effective amount of one or more compounds of the invention. In accordance with preferred embodiments, the present invention provides methods for producing such responses by modulating the activity of mammalian somatostatin receptors by administering an effective amount of one or more compounds of the invention. In the above structural formulas and throughout the present specification, the follow¬ ing terms have the indicated meanings: The C-i.β-alkyl groups specified above are intended to include those alkyl groups of the designated length in either a linear or branched or cyclic configuration. Exam¬ ples of linear alkyl are methyl, ethyl, propyl, butyl, pentyl, and hexyl. Examples of branched alkyl are isopropyl, sec-butyl, tert-butyl, isopentyl, and isohexyl. Examples of cyclic alkyl are C3_6-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. The alkoxy groups, preferably Cι_β-alkoxy groups specified above are intended to include those alkoxy groups of the designated length in either a linear or branched or cyclic configuration. Examples of linear alkyloxy are methoxy, ethoxy, propoxy, bu- toxy, pentoxy, and hexoxy. Examples of branched alkoxy are isopropoxy, sec- butoxy, tert-butoxy, isopentoxy, and isohexoxy. Examples of cyclic alkoxy are C$_Q- cycloalkoxy such as cyclopropyloxy, cyclobutyloxy, cyclopentyloxy and cyclohexy- loxy. In the present context, the term "aryl" is intended to include aromatic rings, such as carbocyclic and heterocyclic aromatic rings selected from the group consisting of phenyl, naphthyl, thienyl, furyl, furanyl, pyridinyl, pyridyl, 1-H-tetrazol-5-yl, thiazolyl, imidazolyl, isoquinolinyl, indolyl, isoindolyl, piperidinyl, piperazinyl, pyridazinyl, pyrimidinyl, thiadiazolyl, pyrazolyl, oxadiazol, oxazolyl, isoxazolyl, thiopheneyl, quino- linyl, pyrazinyl, triazinyl, triazolyl, tetrazolyl or isothiazolyl, optionally substituted by one or more halogen, amino, hydroxy, carboxylic acid, carboxylic amide, nitrile, alde¬ hyde, nitro, trihalogenomethyl, C<ι_6-alkylketone, C-i.β-alkyl, C-|_6-alkoxy or aryl. The term "halogen" is intended to include Chloro (Cl), Fluoro (F), Bromo (Br) and lodo (I). The compounds of the present invention may have one or more asymmetric centres and stereoisomers in the form of separated, pure or partially purified stereoisomers or racemic mixtures thereof are intended to be included in the scope of the invention. General Method A Reaction Scheme I: A - Halogen alogen (4a) 7b Compounds of formula la or formula lb may be prepared as shown in reaction scheme I starting with an arylhalogenide 1 which may be reacted with a diaminoalkyl 2 in an appropriate solvent such as pyridine and under nitrogen at reflux for an ap¬ propriate time. The excess diaminoalkyl and solvent may be removed in vacuo and an apolar solvent such as tetrahydrofuran may be added to precipitate the diami¬ noalkyl salt. The intermediate 3 may be obtained by distillation or chromatography by methods known in the art. The intermediate 3 may be alkylated with an arylalkylhalogenide 4a after treatment with a base such as sodium hydrid under conditions known in the art to give a 1 ,1- disubstituted primary amine 5. Then 5 in a solvent like tetrahydrofuran or ethanol may be reacted with an isothiocyanate 6, prepared as shown in scheme 2, stirred overnight and concentrated in vacuo to afford a crude product 7a. The isothiocy¬ anate may be protected and deprotected according to methods described in the art (e.g. T.W. Greene, Protective Groups in Organic Synthesis, 2nd. edition, John Wiley and Sons, New York, 1991). The crude product 7a may be purified by methods known for those skilled in the art such as chromatography, to yield the final product 7a which is a compound of the general formula la. In the presence of a base such as sodium hydride, and an alkyl halide 4b the compound 7b which is a compound of the general formula lb may be obtained. Reaction Scheme II: DCC, CS 2 , THF pH,)- H 2 N J 2 * D * S = C = N ^ 24> D 8 6 The isothiocyanate 6 as described in scheme I may be prepared from the appropri¬ ate protected primary amine 8 in a solvent like tetrahydrofuran and carbondisulfide in the presence of a reagent such as dicyclohexylcarbodiimide or other coupling rea- gents known in the literature under chilled conditions. The mixture may be stirred overnight and the solvent removed and the residue may be triturated with ether to remove dicyclohexylthiourea. The remaining product may be distilled under vacuum or chromatographed using technics known to those skilled in the art, to yield the iso¬ thiocyanate 6. General Method B Reaction Scheme I Compounds of formula la may be prepared as shown in reaction scheme III starting with an appropriate amine 5, prepared as described in reaction scheme I, and an ac¬ tivated imine 8 in which R3 may be benzoyl(-COPh) or nitrile (-CN) and R 4 may be thiomethoxy (-SCH3), phenoxy (-OPh) or cloride (-CI) in an appropriate solvent such as dimethylformamide or tetrahydrofuran at an appropriate temperature for an ap¬ propriate time to give the intermediate 9. The intermediate 9 may further react with an amine 2 in an appropriate solvent such as pyridine with or without a catalyst e.g. silver salts (e.g. AgNO3) at an appropriate temperature for an appropriate time to form the product 10 which is a compound of the general formula la. When the compound 10 (in which R^ is an activating group such as benzoyl or ni¬ trile) is treated with 1.5 M aqueous hydrogen chloride for an appropriate time at an appropriate temperature the compound 10 (in which R^ is hydrogen) may be formed which is a compound of the general formula la. The intermediates in reaction scheme III may be protected and deprotected accord¬ ing to methods described in the art (e.g. T.W. Greene, Protective Groups in Organic Synthesis, 2nd. edition, John Wiley and Sons, New York, 1991). The guanidine derivatives and their salts thus obtained can be isolated and purified by methods which are known by those skilled in the art. Pharmacology Compounds of the invention are preferred to the extent that they selectively and ef¬ fectively are bound by somatostatin receptor subtypes permanently expressed in eu- kariotic cell lines. It will be recognized that the degree to which a compound is bound by a receptor is known as its binding affinity. The affinity of a compound is commonly expressed as the inhibitory concentration at which the compound is able to displace 50% of another compound already bound to the receptor (IC 50 ). In the case of ligand- binding studies at somatostatin receptors, the compound that is displaced is a radio- active agonist, e.g. 125 l-Tyr 11 -SRIF-14, at the receptor. It is preferred in accordance with the present invention that a compound possess a clinically effective IC 50 in at least one mammal; that is, it should possess an IC 50 which is low enough to inhibit binding of radiolabelled agonist to somatostatin receptors while causing a minimum of unacceptable side effects in the mammal. As will be recognized, clinically effective concentrations vary depending on a number of factors, such as the pharmacokinetic characteristics and stability of the compound under study and thus must be deter¬ mined empirically for each compound and each factor. In general, it is desired that the potency of a compound of the invention be as great as possible, preferable greater than or equal to the native somatostatin. Compounds displacing radiolabelled agonist at somatostatin receptors could belong to one of two classes, either agonists or antagonists. Simple ligand-binding studies will not distinguish between these two classes. All five somatostatin receptor subtypes (ie. SST1 , SST2, SST3, SST4 and SST5) have been shown to inhibit the activity of adenylyl cyclase via the G protein subunit G, (Patel, Y.C. et al. Biochem. Biophys.Res.Commun., 198:605-612, 1994). By direct activation of adenylyl cyclase by forskolin the inhibitory action of somato¬ statin agonists could be employed. Compounds specifically reversing the inhibitory action of SRIF on cyclic AMP accumulation will be termed somatostatin receptor an¬ tagonists. Those skilled in the art will appreciate that a wide variety of prophylactic, diagnostic, and therapeutic treatments may be prepared from the compounds and compositions of this invention, due to agonism or antagonism at somatostatin receptors. For ex¬ ample, by administering an effective amount of compound, prophylactic or therapeu¬ tic responses can be produced in a human or some other type mammal. Preferred responses are modulation of glucagon and insulin secretion to treat type I and type II diabetes; inhibition of cell proliferation and growth to treat various endocrine and exocrine tumours; modulation of growth hormone secretion to treat dwarfism, ac- romegaly, and other growth abnormalities; modulation of immune responses to treat autoimmune diseases, rheumatoid arthritis, and other inflammations; modulation of neuronal activity to treat diseases related to the central nervous system, i.e. pain, anxiety, memory disorders, affective disorders, and Alzheimers disease; modulation of intestinal water uptake to treat congestion and diarrhea; inhibition of arterial smooth muscle cell proliferation to treat restenosis and arteriosclerosis; inhibition of airway mucous secretion to treat asthma and mucoviscidosis; modulation of lipid metabolism and regulation of energy balance to treat obesity; inhibition of acid se- cretion to treat ulcer; inhibition of pancreatic secretions to treat acute pancreatitis. It will be appreciated that the production of prophylactic or therapeutic responses in¬ cludes the initiation or enhancement of desirable responses, as well as the cessation or suppression of undesirable responses. As can be seen, the present invention provides a variety of compounds which effec¬ tively and selectively are bound to somatostatin receptors. The compounds are ca¬ pable of forming pharmaceutically acceptable salts with various inorganic and or¬ ganic acids, and such salts are also within the scope of this invention. Examples of such salts are acid addition salts including acetate, adipate, benzoate, benzene- sulfonate, bisulfate, butyrate, citrate, camphorate, camphorsulfonate, ethanesul- fonate, fumarate, hemisulfate, heptanoate, hexanoate, hydrochloride, hydrobromide, hydroiodide, lactate, maleate, methanesulfonate, 2-naphthalenesulfonate, nitrate, oxalate, pamoate, persulfate, picrate, pivalate, propionate, succinate, sulfate, tar- trate, tosylate, and undecanoate. The salts may be formed by conventional means, such as by reacting the free base form of the product with one or more equivalents of the appropriate acid in a solvent or medium in which the salt is insoluble, or in a sol¬ vent such as water, which is later removed in vacuo or by freeze drying. The salts also may be formed by exchanging the anions of an existing salt for another anion on a suitable ion exchange resin. In another aspect, the present invention relates to a pharmaceutical composition comprising, as an active ingredient, a compound of the general formula la or formula lb or a pharmaceutically acceptable salt thereof together with a pharmaceutically ac¬ ceptable carrier or diluent. Pharmaceutical compositions containing a compound of the present invention may be prepared by conventional techniques, e.g. as described in Remington's Pharma¬ ceutical Sciences. 1985. The compositions may appear in conventional forms, for example capsules, tablets, aerosols, solutions, suspensions or topical applications. The pharmaceutical carrier or diluent employed may be a conventional solid or liquid carrier. Examples of solid carriers are lactose, terra alba, sucrose, cyclodextrin, talc, gelatin, agar, pectin, acacia, magnesium stearate, stearic acid or lower alkyl ethers of cellulose. Examples of liquid carriers are syrup, peanut oil, olive oil, phospholipids, fatty acids, fatty acid amines, polyoxyethylene or water. Similarly, the carrier or diluent may include any sustained release material known in the art, such as glyceryl monostearate or glyceryl distearate, alone or mixed with a wax. If a solid carrier is used for oral administration, the preparation may be tabletted, placed in a hard gelatin capsule in powder or pellet form or it can be in the form of a troche or lozenge. The amount of solid carrier will vary widely but will usually be from about 25 mg to about 1 g. If a liquid carrier is used, the preparation may be in the form of a syrup, emulsion, soft gelatin capsule or sterile injectable liquid such as an aqueous or non-aqueous liquid suspension or solution. A typical tablet which may be prepared by conventional tabletting techniques may contain: Core: Active compound (as free compound or salt thereof) 100 mg Colloidal silicon dioxide (Aerosil) 1.5 mg Cellulose, microcryst. (Avicel) 70 mg Modified cellulose gum (Ac-Di-Sol) 7.5 mg Magnesium stearate Coating: HPMC approx. 9 mg * Mywacett 9-40 T approx. 0.9 mg *Acylated monoglyceride used as plasticizer for film coating. For nasal administration, the preparation may contain a compound of formula la or formula lb dissolved or suspended in a liquid carrier, in particular an aqueous carrier, for aerosol application. The carrier may contain additives such as solubilizing agents, e.g. propylene glycol, surfactants, absorption enhancers such as lecithin (phosphatidylcholine) or cyclodextrin, or preservatives such as parabenes. Generally, the compounds of the present invention are dispensed in unit dosage form comprising 50-200 mg of active ingredient together with a pharmaceutically ac¬ ceptable carrier per unit dosage. The dosage of the compounds according to this invention is suitably 1-500 mg/day, e.g. about 100 mg per dose, when administered to patients, e.g. humans, as a drug. It has been demonstrated that compounds of the general formula la or formula lb possess the ability to bind to human somatostatin receptors. The compounds may therefor be used in the treatment of conditions which require high somatostatin re¬ ceptor affinity. Thus, in a particular aspect, the present invention relates to a pharmaceutical com¬ position for binding to somatostatin receptors, the composition comprising, as an ac¬ tive ingredient, a compound of the general formula la or formula lb or a pharmaceuti¬ cally acceptable salt therof together with a pharmaceutically acceptable carrier or di- luent. In a further aspect, the present invention relates to a method of binding to somato¬ statin receptors, the method comprising administering to a subject in need thereof an effective amount of a compound of the general formula la or formula lb or a pharma- ceutically acceptable salt thereof. In a still further aspect, the present invention relates to the use of a compound of the general formula la or formula lb or a pharmaceutically acceptable thereof for the preparation of a medicament for binding to the somatostatin receptors. Those skilled in the art will appreciate that a wide variety of prophylactic, diagnostic, and therapeutic treatments may be prepared from the synthetic compounds and compositions of the invention, due in large part to the competition - that is, agonism or antagonism - of these moieties with the naturally- occuring SRIF or SRIF-28. For example, by administering an effective amount of a compound of the invention, pro¬ phylactic or therapeutic responses can be produced in a human or some other type mammal. Preferred responses are produced by modulating - that is, increasing, de¬ creasing or otherwise modifying - the activity of at least one somatostatin receptor subtype (ie. SST1 , SST2, SST3, SST4 and SST5). It will be appreciated that the production of prophylactic or therapeutic responses includes the initiation or en¬ hancement of desirable responses, as well as the cessation or suppression of unde¬ sirable responses. The compounds of formula la or formula lb may be used in the treatment of disorders with an aetiology comprising or associated with excess GH-secretion, gastro¬ intestinal disorders, malignant cell proliferative diseases, angiogenesis, or in preven¬ tion or combating graft vessel diseases, restenosis and vascular occlusion following vascular injury. The compounds of formula la or formula lb may be administered in pharmaceutically acceptable acid addition salt form or, where appropriate, as a alkali metal or alkaline earth metal or lower alkylammonium salt. Such salt forms are believed to exhibit ap¬ proximately the same order of activity as the free base forms. Optionally, the pharmaceutical composition of the invention may comprise a com¬ pound of formula la or formula lb combined with one or more compounds exhibiting a different activity, e.g., an antibiotic or other pharmacologically active material. The route of administration may be any route which effectively transports the active compound to the appropriate or desired site of action, such as oral, nasal, pulmo¬ nary, transdermal or parenteral, the oral route being preferred. EXAMPLES: The process for preparing compounds of formula la or formula lb and preparations containing them is further illustrated in the following exampels, which however, are not to be construed as limiting. The structures of the compounds are confirmed by either elemental analysis (MA) nuclear magnetic resonance (NMR) or mass spectrometry (MS). NMR shifts (d) are given in parts per million (ppm) and only selected peaks are given, m.p. is melting point and is given in °C and is not corrected. Column chromatography was carried out using the technique described by W.C. Still at al, J. Org. Chem. 1978, 43, 2923- 2925 on Merck silica gel 60 (Art 9385). Compounds used as starting materials are either known compounds or compounds which can readily be prepared by methods known per se. Abbrevations: TLC: thin layer chromatography DMSO: dimethylsulfoxide min: minutes h: hours HPLC-Analysis: Method A. The RP-HPLC analysis was performed using UV detection at 254nm and a Lichro- sorp RP-18 5mM column, which was eluted at 1 ml/minute. The column was equili¬ brated with 20% acetonitrile in a buffer consiting of 0.1 M ammonium sulfate, which was adjusted to pH 2.5 with 4M sulfuric acid and eluted by a gradient of 20% to 80% acetonitrile in the same buffer over 30 minutes. The gradient was then extended to 100% acetonitrile over 5 minutes followed by isocratic elution with 100% acetonitrile for 6 minutes. Biological assays The affinity of somatostatin receptor ligands of nonpeptide origin according to the in¬ vention (including the compounds covered by formula la and lb) to the somatostatin receptor proteins selected from SST1 , SST2, SST3, SST4 and SST5, may be de¬ tected using the assays described below. The skilled person will know which ad¬ justments/modifications to make in order to screen for specific ligands having affinity to one or more of the SST receptor subtypes 1-5. Moreover, in order to screen large compound libraries to find the present ligands, conventional techniques (see e.g. Amersham™ SPA Technology) known to the skilled person may be used to modify the assays. One way of producing the present ligands is to provide a compound li¬ brary of nonpeptide origin using conventional techniques (see e.g. Combinatorial chemistry in the discovery and development of drugs. Doyle, P.M., Journal Of Che¬ mical Technology And Biotechnology (1995) Vol. 64, 317-24) well-known to the skil¬ led person, and screen for such ligands using the assays described below optionally with modifications, thereby providing somatostatin receptor ligands according to the invention. Cell lines expressing SST receptor subtypes: BHK cells (tk- ts13, ATCC CRL# 1632) and HEK 293 cells (ATCC CRL# 1573) were grown to 20-40% confluency in a tissue culture dish in Dulbeccos Modified Eagle Medium (DMEM) containing 1% penicillin / streptomycin , 10% foetal bovine serum, and 1% Glutamax™. Prior to transfection, the cells were washed twice with calcium- free PBS after which 20 ml of serum-free DMEM was added to the cells. Transfection was carried out as described previously (product description: Lipofec- tamin, Gibco BRL cat. no. 18324-012). Briefly, 10 μg of cDNA encoding a SST re¬ ceptor subtype inserted into the mammalian expression vector pcDNA3 (Invitrogen) was diluted in 300 μl of sterile water. 30 μg of Lipofectamin was diluted in 300 μl of sterile water. The cDNA and Lipofectamin solutions were mixed and left at room temperature for 15 minutes. The Lipofectamin/cDNA mixture was added drop-wise to the cells (HEK 293 cells for SST 2 , BHK for the other receptor subtypes) while gently swirling the plates. The cells were then incubated for 16-24 hours, after which the medium was replaced with standard medium containing 1 mg/ml Geneticin (G-418 sulfate). Resistant colonies appearing after 1-2 weeks were isolated and propagated for further characterization. Binding assay: Cells expressing individual SST receptor subtypes were resuspended in buffer (50 mM Tris-HCl (pH 7.4), 1 mM EGTA, 5 mM MgCI 2 ), and homogenised. Membranes were washed twice in buffer by homogenisation and centrifugation. Final membrane pellets were resuspended at a protein concentration of 125 μg/ml in buffer. Binding assays using 75 pM 125 l-Tyr 11 -SRIF (Amersham, IM-161) were done in duplicates in minisorb polypropylene tubes in a volume of 250 μl. The assays were incubated at 30-37 °C for 30-90 min depending on receptor subtype. Binding was terminated by filtration through Whatman GF/B glass fiber filters pre-soaked for 4 hrs. in 0.5% poly¬ ethyleneimine and 0.1 % BSA. Filters were washed three times with 5 ml ice-cold 0.9% saline and counted in a Packard Cobra II Gamma Counter. Functional assay: Cells expressing human SST receptors were seeded in 24-well tissue culture multi- dishes at 200,000 cells/well and grown for 16-20 hours. The medium was removed, and fresh DMEM medium, supplemented with 1) 1 mM 3-isobutyl-1-methylxanthine (IBMX), 2) 10 μM forskolin or medium, and 3) medium, SRIF, SST analogue, or compound was added. The plates were incubated for 15-30 min at 37°C, the reacti- on medium removed and the cells lysed with 0.1 M sodium hydroxide. Following neutralisation with 0.1 M hydrochloric acid an aliquot was removed for cAMP deter¬ mination using Amersham SPA RIA (RPA 538). EXAMPLE 1 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(1 H-imidazol-4- yl)propyl)thiourea dihydrochloride To a solution of propane-1,3-diamine (310 ml, 3.63 mol) in dry pyridine (75 ml) kept under an atmosphere of nitrogen 2-bromopyridine (70 ml, 0.73 mol) was added. The reaction mixture was heated at reflux for 18 h, cooled and the volatiles evaporated in vacuo. To the residue was added tetrahydrofuran (1 I) and the precipitate was filtered off and washed with tetrahydrofuran (0.5 I). The solvent was evaporated in vacuo and the residue purified by distillation at 95-97 °C and 2 *10 "2 mbar affording 83.37 g (76 %) of N-(pyridin-2-yl)propane-1 ,3-diamine. 1 H NMR (200 MHz, DMSO-d β ) d 1.20 (bs, 2H, NH 2 ), 1.74 (p, 2H), 2.82 (t, 2H), 3.34 (q, 2H, CH 2 -NH), 4.86 (bs, 1 H, NH), 6.35 (dt, 1H), 6.51 (ddd, 1 H), 7.37 (ddd, 1 H), 8.04 (ddd, 1H). To a mixture of sodium hydride (5.86 g, 60 % dispersion in mineral oil, 0.1415 mol) in dry dimethylsulfoxide (250 ml) was slowly added a solution of N-(pyridin-2- yl)propane-1 ,3-diamine (20 g, 0.1323 mol) in dry dimethylsulfoxide (50 ml) at room temperature under an atmosphere of nitrogen. The reaction mixture was stirred until gas evolution was ceased. A solution of 4-bromobenzylbromide (36.09 g, 0.1415 mol) in dry dimethylsulfoxide (100 ml) was slowly added at room temperature. The reaction mixture was stirred for 48 h at room temperature. The reaction mixture was poured onto ice water (500 ml) and extracted with ethyl acetate (3 x 250 ml). The combined organic extracts were washed with water (3 x 150 ml), dried (MgSO 4 ), filtered and the solvent evaporated in vacuo. The residue (40.56 g) was washed with n-heptane (30 ml) which afforded 36.77 g of crude N-(4-bromobenzyl)-N-(pyridin-2- yl)propane-1 ,3-diamine. 20 g crude product was purified by column chromatography on silica gel (900 ml) using dichloremethane/methanol/triethylamine 9:0.5:0.5 as eluent affording 13.75 g (70 %) of N-(4-bromobenzyl)-N-(pyridin-2-yl)propane-1 ,3- diamine as an oil. 1 H NMR (200 MHz, CDCI 3 ) d 1.64 (s, 2H, NH 2 ), 1.74 (t, 2H), 2.72 (t, 2H), 3.60 (t, 2H, C/-/ 2 -N), 4.67 (s, 2H, CH 2 -Ph), 6.41 (d, 1H), 6.53 (dd, 1H), 7.07 (d, 2H), 7.33 - 7.41 (m, 3H), 8.13 (dt, 1H). To a solution of N,N-dicyclohexylcarbodiimide (2.08 g, 10 mmol) in dry tetrahydrofuran (20 ml) was slowly added at -10 °C a solution of N-(4-bromobenzyl)-N-(pyridin-2-yl)- propane-1 ,3-diamine (3.20 g, 10 mmol) and carbondisulfide (4.3 ml, 70 mmol) in dry tetrahydrofuran (20 ml) under an atmosphere of nitrogen. The mixture was stirred at - 10 °C for 3 h and for 48 h at room temperature. The reaction mixture was filtered and the solvent evaporated io vacuo. The residue (5.29 g) was extracted with diethyl ether (3 x 20 ml) and the combined organic extracts were evaporated in vacuo affording 3.2 g (88 %) of N-(4-bromobenzyl)-N-(3-isothiocyanatopropyl)-N-(pyridin-2-yl)amine as an oil. TLC: R f = 0.72 (SiO 2 ; ethyl acetate/n-heptan = 1 :1). 1 H NMR (200 MHz, CDCI 3 ) d 2.00 (q, 2H), 3.57 (t, 2H), 3.68 (t, 2H), 4.66 (s, 2H), 6.41 (d, 1H), 6.58 (dd, 1H), 7.07 (d, 2H), 7.35 - 7.43 (m, 3H), 8.15 (dd, 1H). N-(4-bromobenzyl)-N-(3-isothiocyanatopropyl)-N-(pyridin-2-yl)amine(1 g, 2.76 mmol) and 3-(1-triphenylmethylimidazol-4- yl)propylamine (1.014 g, 2.76 mmol) were dissolved in chloroform (10 ml) and heated at reflux for 4 h. The solvent was removed by evaporation in vacuo and the residue (3.09 g) purified by column chromatography on silica gel (400 ml) using ethyl acetate/methanol/ triethylamine 9:0.5:0.5 as eluent affording 1.59 g (80 %) of pure 1-[3-(1-triphenylmethylimidazol-4- yl)propyl]-3-[3-[N-(4-bromobenzyl)-N-(pyridin-2-yl)amino]propyl]thiourea. TLC: R f = 0.59 (SiO 2 ; ethyl acetate/methanol/triethylamine = 9:0.5:0.5). 1 H NMR (200 MHz, CDCI 3 ) d 1.90 (m, 6H), 2.62 (t, 2H), 3.44 - 3.68 (m, 6H), 4.55 (s, 2H, CH 2 -Ph), 6.33 (d, 1H), 6.49 (dd, 1H), 6.56 (s, 1H), 6.98 - 7.11 (m, 9H), 7.30 - 7.39 (m, 11H), 8.06 (d, 1H). To a solution of the above thiourea (1.59 g, 2.215 mmol) in ethanol (50 ml), 1 N hydrochloric acid (16 ml) was added and the reaction mixture was heated to 50 °C for 10 h. The cooled reaction mixture was washed with diethyl ether (3 x 30 ml) and the aqueous phase evaporated in vacuo. The residue was extracted with absolute ethanol (3 x 20 ml) and evaporated in vacuo followed by drying in vacuo affording 1.23 g (99 %) of the title compound as an amorphous powder. Η NMR (200 MHz, MeOD-d 3 ) d 2.0 (m, 4H), 2.77 (t, 2H), 3.57 (m, 4H), 3.76 (t, 2H), 4.90 (s, 2H, CH 2 -Ph), 6.99 (t, 1H), 7.19 (d, 2H), 7.26 (d, 1 H), 7.36 (s, 1 H), 7.50 (d, 2H), 7.94 (d, 1 H), 8.02 (dd, 1 H), 8.78 (d, 1H). EXAMPLE 2 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(morpholin-4- yl)propyl)thiourea To a solution of N-(4-bromobenzyl)-N-(pyridin-2-yl)pro-pane-1 ,3-diamine (1.0 g, 3.123 mmol) in chloroform (40 ml) was added 3-morpholinopropyl isothiocyanate (593 mg, 3.123 mmol) and the reaction mixture was stirred for 20 h at reflux temperature. To the reaction mixture was added 10 drops of 3-morpholinopropyl isothiocyanate and the reaction mixture was stirred for an additional 4 h at reflux temperature. The volatiles were evaporated in vacuo and the residue (2.05 g) was dissolved in ethyl acetate (20 ml) and left over night at room temperature. The precipitate was filtered off and washed with ethyl acetate and dried affording 1.20 g (76 %) of the title compound as a solid. TLC: R f = 0.39 (SiO 2 ; Ethyl acetate/Methanol/Triethylamine = 90:5:5) M.p. 121-123 °C HPLC retention time = 6.68 minutes (5 mM C18 4 x 250 mm column, eluting with 25% acetonitrile/0.1 N aqueous ammonium sulphate, pH = 2.5, at room temperature) 1 H-NMR (200 MHz, CDCI 3 ) d 1.84 (m, 4H), 2.49 (m, 6H), 3.53 (m, 4H), 3.71 (m, 6H), 4.56 (s, 2H, CH 2 -Ph), 6.36 (d, 1 H), 6.57 (m, 1H), 7.04 (d, 1 H), 7.22 (bs, 1H), 7.32 - 7.45 (m, 3H), 7.91 (bs, 1 H), 8.15 (d, 1 H). EXAMPLE 3 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-N,N- dimethylaminopropyl)thiourea To a solution of N-(4-bromobenzyl)-N-(pyridin-2-yl)pro- pane-1 ,3-diamine (1.0 g, 3.123 mmol) in chloroform (40 ml) was added 3-(dimethylamino)propyl isothiocyanate (460 mg, 3.123 mmol) and the reaction mixture was stirred for 5 h at reflux temperature. The volatiles were evaporated in vacuo and the residue (1.69 g) was purified by column chromatography on silica gel (180 ml) using ethyl acetate/methanol/triethylamine 7:2.5:0.5 as eluent affording (1.41 g) of a syrup which was crystallised from n-heptane affording 1.23 g (85 %) of the title compound as a solid. TLC: R f = 0.39 (SiO 2 ; Ethyl acetate/Methanol/Triethylamine = 70:25:5) M.p. 79-81 °C HPLC retention time = 6.09 minutes (5 mM C18 4 x 250 mm column, eluting with 25 % acetonitrile/0.1 N aqueous ammonium sulphate, pH = 2.5, at room temperature) Η-NMR (400 MHz, CDCI 3 ) d 1.72 (p, 2H), 1.84 (p, 2H), 2.19 (s, 6H), 2.40 (t, 2H), 3.48 (bs, 4H), 3.68 (t, 2H), 4.59 (s, 2H, CH 2 -Ph), 6.37 (d, 1H), 6.56 (dd, 1 H), 7.04 (d, 2H), 7.38 (m, 3H), 8.17 (bd, 1H). EXAMPLE 4 1-[3-[N-(4-bromobenzyl)-N-(quinolin-2-yl)amino] propyl]- 2-Benzoyl-3-[3-(1H- imidazol-4-yl)propyl]guanidine To a solution of propane-1 ,3-diamine (65.1 ml, 0.764 mol) in dry pyridine (25 ml) kept under an atmosphere of nitrogen 2-chloro-quinoline (25 g, 0.153 mol) was added. The reaction mixture was heated at reflux temperature for 18 h. To the cooled reaction mixture was added tetrahydrofuran (100 ml) and the precipitate was filtered off and washed with tetrahydrofuran (2 x 50 ml). The solvent was evaporated in vacuo and the residue purified by distillation at 154 °C and 2.5 *10 '2 mbar affording 25.34 g (82 %) of N-(quinolin-2-yl)propane-1 ,3-diamine as a crystallising oil. H NMR (200 MHz, CDCI 3 ) d 1.37 (bs, 2H, NH 2 ), 1.77 (p, 2H), 2.83 (t, 2H), 3.59 (q, H, CH 2 -NH), 5.22 (bs, 1H, NH), 6.59 (d, 1 H), 7.17 (dt, 1 H), 7.49 (m, 2H), 7.66 (d, 1H), 7.76 (d, 1H). To a mixture of sodium hydride (2.64 g, 60 % dispersion in mineral oil, 63.79 mmol) in dry dimethylsulfoxide (100 ml) was slowly added a solution of N-(quinolin-2- yl)propane-1 ,3-diamine (12 g, 56.62 mmol) in dry dimethylsulfoxide (25 ml) at room temperature under an atmosphere of nitrogen. The reaction mixture was stirred until gas evolution was ceased. To the resulting mixture a solution of 4- bromobenzylbromide (16.27 g, 63.79 mmol) in dry dimethylsulfoxide (50 ml) was slowly added at room temperature. The reaction mixture was stirred for 4 days at room temperature poured on to ice water (800 ml) and extracted with ethyl acetate (5 x 150 ml). The combined organic extracts were washed with water (4 x 150 ml), dried (MgSO 4 ), filtered and the solvent evaporated in vacuo. The residue (22.27 g) was washed with n-heptane (30 ml) which afforded 20.41 g of crude N-(4-bromobenzyl)- N-(quinolin-2-yl)propane-1 ,3-diamine which was purified by column chromatography on silica gel (900 ml) using a mixture of dichloromethane/methanol/triethylamine 9:0.5:0.5 as eluent affording 13.9 g (63 %) of N-(4-bromobenzyl)-N-(quinolin-2- yl)propane-1 ,3-diamine as an oil. 1 H NMR (200 MHz, CDCI 3 ) d 1.76 (m, 4H), 2.74 (t, 2H), 3.78 (t, 2H), 4.80 (s, 2H), 6.77 (d, 1 H), 7.16 (m, 3H), 7.41 (d, 2H), 7.55 (m, 2H), 7.67 (d, 1H), 7.81 (d, 1 H). To a solution of the above amine (8.0 g, 21.604 mmol) in dichloromethane (100 ml) was added N-benzoyl-dimethyldithioimidocarbonate (4.87 g, 21.604 mmol) and the reaction mixture was stirred at room temperature for 20 h. The solvent was evaporated in vacuo and the residue was purified by column chromatography on silica gel (900 ml) using a mixture of ethyl acetate and heptane 1 :2 as eluent affording 10.92 g (92 %) of 1-benzoyl-3-[3-[N-(4-bromobenzyl)-N-(quinolin-2- yl)amino]-propyl]-2-methylisothiourea. To a solution of the above isothiourea (5.0 g, 9.133 mmol) in dry pyridine (70 ml) was added 3-(1/-/-imidazol-4-yl)propyl amine (1.26 g, 10.05 mmol) and the resulting mixture was stirred at reflux temperature for 10 h followed by stirring at room temperature for 48 h. The solvent was evaporated in vacuo and the residue was purified by column chromatography on silica gel (600 ml) using a mixture of dichloromethane/methanol/triethylamine 9:0.5:0.5 as eluent affording 3.31 g (58 %) of the title compound as an amorphous solid. 1 H NMR (200 MHz, CDCI 3 ) d 1.84 (bs, 2H), 2.01 (m, 2H), 2.59 (m, 2H), 3.24 - 3.70 (m, 4H), 3.80 (t, 2H), 4.78 (s, 2H), 6.69 (s, 1H), 6.76 (d, 1 H), 7.09 (d, 2H), 7.22 (dt, 2H), 7.29 - 7.80 (m, 9H), 8.18 (d, 2H). HPLC retention time = 26.10 minutes (5 mM C184 x 250 mm column, eluting with a gradient of 15 % acetonitrile/0.1 N aqueous ammonium sulphate to 25 % acetoπitrile/0.1 N aqueous ammonium sulphate, pH = 2.5, over 10 minutes at room temperature). EXAMPLE 5 1-[3-[N-(4-Bromo-benzyl)-N-(quinolin-2-yl)amino]-propyl]- 3-[3-(1/-/-imidazol-4- yl)propyl]guanidine trihydrochloride The above benzoyl guanidine (120 mg, 0.19 mmol) was dissolved in 1.5 N hydrochloric acid (3.6 ml) and stirred at 100 °C for 16 h in an ampoule. The cooled reaction mixture was washed with diethyl ether (2 x 2 ml) and the aqueous phase was evaporated in vacuo. The residue was dissolved in ethanol (10 ml) and evaporated in vacuo. This evaporation procedure was repeated twice. This afforded 116 mg (98 %) of the title compound as an amorphous solid. Η NMR (200 MHz, MeOD-d 3 ) d 1.97 (m, 2H), 2.10 (m, 2H), 2.84 (t, 2H), 3.30 (m, 2H), 3.40 (t, 2H), 4.00 (m, 2H), 5.11 (s, 2H), 7.25 (d, 2H), 7.40 (d, 2H), 7.55 (m, 3H), 7.80 (t, 1 H), 7.90 (d, 1 H), 8.30 (d, 1H), 8.90 (d, 1H), 8.80 (s, 1H). HPLC retention time = 7.15 minutes (5 mM C184 x 250 mm column, eluting with a gradient of 16 % acetonitrile/0.1 N aqueous ammonium sulphate to 25 % acetonitrile/0.1 N aqueous ammonium sulphate, pH = 2.5, over 10 minutes at room temperature). EXAMPLE 6 1 -(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) ethyl)-3-(3-(1 H-imidazol- 4-yl)propyl)thiourea A mixture of 2,5-dibromopyridine (10.0 g, 42.2 mmol) and pyridine (4.24 g, 53.6 mmol) in 1 ,2-diaminoethane (43 mL) was refluxed under nitrogen for 18 h. The reaction mixture was evaporated under reduced pressure, cooled, and the resulting residue was treated with THF (150 mL) to yield a white precipitate. The precipitate was filtered and washed with additional THF (100 mL). Evaporation of the filtrate afforded a brown oil which was vacuum distilled to give 6.48 g (71%) N-1 -(5- bromopyrid-2-yl)ethane-1 ,2-diamine as a light yellow oil. bp 134-142°C (0.6 mm). 1 H NMR (90 MHz CDCI 3 )d 1.33 (s, 2 H, NH 2 ), 2.92 (t, 2 H), 3.29 (m, 2 H), 5.22 (br s, 1 H, NH), 6.31 (d, J = 9 Hz, 1 H, pyridine H-3), 7.44 (dd, J = 2.7 Hz, 9 Hz, 1 H, pyridine H-4), 8.09 (d, J = 2.5 Hz, 1 H, pyridine H-6). 13 C NMR (90 MHz CDCI 3 )d 41.22, 44.74, 106.72, 108.67, 139.55, 148.54, 148.70. A 60 % mineral oil dispersion of sodium hydride (0.584 g, 14.6 mmol) and N-1-(5- bromopyrid-2-yl)ethane-1 ,2-diamine (3.00 g, 13.9 mmol) in DMSO (30 mL) was stirred for 2 h under nitrogen. The suspension was cooled to 0-5 °C and treated dropwise with 3,4-dichlorobenzyl chloride (2.71 g, 13.9 mmol) in DMSO (15 mL). After stirring overnight at room temperature, the reaction mixture was poured into 200 mL of an ice-water mixture. The mixture was extracted with ethyl acetate (3 x 75 mL), and the combined ethyl acetate extracts were washed with water (2 x 50 mL), dried (Na 2 SO 4 ), filtered, and evaporated to yield an oil. Flash chromatography on silica gel using CH 2 CI 2 90: CH 3 OH 5: Et 3 N 5 as the solvent system gave 3.5 g (67%) of N-1-(5-bromopyrid-2-yl)-1-(3,4-dichlorobenzyl)ethane-1 ,2-diamine as a yellow oil. 1 H NMR (90 MHz CDCI 3 )d 1.45 (s, 2 H, NH 2 ), 2.92 (t, 2 H, NCH 2 ), 3.57 (m, 2 H, CH 2 NH 2 ), 4.72 (s, 2 H, ArCH 2 ), 6.39 (d, J = 9 Hz, 1 H, pyridine H-3), 7.32 (m, 4 H, ArH), 8.16 (d, J = 2 Hz, 1 H, pyridine H-6). 13 C NMR (90 MHz CDCI 3 )d 39.82, 51.47, 51.95, 107.00, 107.27, 126.23, 128.77, 130.62, 131.04, 132.73, 138.85, 139.77, 148.66, 156.62. A mixture of dicyclohexylcarbodiimide (DCC) (2.74 g, 13.2 mmol) and carbon disulfide (10.1 g, 132.6 mmol) in THF (30 mL) was cooled to -10 °C in an ice-salt bath and treated dropwise with a solution of N-1-(5-bromopyrid-2-yl)-1-(3,4- dichlorobenzyl)ethane-1 ,2-diamine (5.00 g, 13.2 mmol) in THF (20 mL). The reaction mixture was allowed to warm to room temperature and was stirred overnight under nitrogen. Removal of the solvent under reduced pressure afforded a white solid. The solid was triturated with diethyl ether (200 mL), and the dicyclohexylthiourea was removed by filtration. The filtrate was evaporated, and acetonitrile (100 mL) was added to the resulting residue. The remaining dicyclohexyl-thiourea was filtered, and the filtrate was evaporated under vacuum to afford an oil. Flash chromatography on silica gel using CH 2 CI 2 50: hexane 50: Et 3 N 1 gave 4.31 g (78%) of 2-[N-(5- bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)] aminoethyl isothiocyanate as a white solid. Recrystallization from diethyl ether/hexane gave an analytical sample, mp 83-85 °C. Η NMR (90 MHz CDCI 3 )d 3.84 (m, 4 H), 4.69 (s, 2 H, ArCH 2 ), 6.33 (d, J = 8.3 Hz, 1 H, pyridine H-3), 7.40 (m, 4 H), 8.20 (d, J = 2 Hz, 1 H, pyridine H-6). 13 C NMR (90 MHz CDCI 3 )d 43.34, 49.19, 52.71 , 107.70, 108.19, 125.74, 128.34, 130.83, 140.10, 148.71 , 155.65. Anal. Calcd for C 15 H 12 BrCI 2 N 3 S: C, 47.01 ; H, 3.16; N, 14.62. Found: C, 46.93; H, 3.32; N, 14.56. A suspension of 3-[1-(triphenylmethyl)imidazol-4-yl]propylamine1 (0.87 g, 2.64 mmol) in THF (40 mL) was stirred under a nitrogen atmosphere at 0-5 C C and treated dropwise with a solution of 2-[N-(5-bromopyrid-2-yl)-N-(3,4- dichlorobenzyl)]aminoethyl isothiocyanate (1.10 g, 2.64 mmol) in THF (15 mL). The reaction mixture was allowed to warm to room temperature and was stirred overnight. TLC on silica gel using EtOAc 90: CH 3 OH 5: Et 3 N 5 indicated that considerable starting material remained. The reaction mixture was refluxed for 24 h, and the solvent was removed under reduced pressure to yield a white foam. Flash chromatography on silica gel using EtOAc 90: CH 3 OH 5: Et 3 N 5 as the solvent afforded 1.72 g (87%) of the trityl-protected thiourea as a colorless oil. The oil was suspended in 2 N HCI (40 mL) and was refluxed for 8 h under nitrogen. The precipitated triphenylmethanol was filtered, and the filtrate was evaporated under reduced pressure to yield a foam. The foam was suspended in 1 N NaOH (60 mL) and extracted with EtOAc (3 x 75 mL). The combined ethyl acetate extracts were washed with water (2 x 50 mL), dried (Na 2 SO 4 ), filtered, and evaporated to yield upon trituration with hexane 765 mg (57%) the title compound as a white hygroscopic foam. 1 H NMR (90 MHz CDCI 3 )d 1.90 (m, 2 H), 2.64 (m, 6 H), 3.55 (m, 6 H), 4.62 (s, 2 H, ArCH 2 ), 6.44 (d, J = 9 Hz, 1 H, pyridine H-3), 7.20-7.55 (m, 8 H, NHC=SNH and ArH), 8.09 (d, J = 2.5 Hz, 1 H, pyridine H-6). 13 C NMR (90 MHz CDCI 3 )d 23.49, 28.87, 42.42, 43.50, 47.84, 51.79, 107.51 , 108.19, 115.99, 126.01 , 128.50, 130.78, 131.31 , 132.89, 134.35, 137.22, 137.98, 140.26, 148.04, 156.62, 181.75. Anal. Calcd for C 21 H 23 BrCI 2 N 6 S: C, 46.50; H, 4.28; N, 15.50. Found: C, 45.13; H, 5.00; N, 16.22 EXAMPLE 7 1-(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) ethyl)-3-(2-(1H-imidazol- 4-yl)ethyl)thiourea A suspension of histamine (320 mg, 2.88 mmol) in THF (40 mL) was treated with a solution of 2-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)]aminoethyl isothiocyanate (1.20 g, 2.88 mmol) in THF (15 mL). The reaction mixture was stirred for 48 h under a nitrogen atmosphere, and the solvent was removed under reduced pressure to afford a foam. Flash chromatography on silica gel using a solvent system of EtOAc 90: CH 3 OH 5: concentrated NH 4 OH 5 gave 987 mg (67%) of the title compound as a white foam, mp 72-78 °C. 1 H NMR (90 MHz CDCI 3 )d 2.85 (m, 2 H), 3.68 (m, 6 H), 4.59 (s, 2 H, ArCH 2 ), 6.40 (d, 1 H, pyridine H-3), 6.80-7.50 (m, 9 H, NHC=SNH and ArH), 8.02 (d, 1 H, pyridine H- 6). 13 C NMR (90 MHz CDCI 3 )d 27.66, 42.81 , 47.74, 51.80, 107.49, 108.19, 116.16, 125.96, 130.84, 131.33, 132.95, 134.90, 135.55, 137.82, 140.32, 148.12, 156.63, 181.71. Anal. Calcd for C 20 H 21 BrCI 2 N e S: C, 45.46; H, 4.01 ; N, 15.91. Found: C, 44.90; H, 424; N, 15.79 EXAMPLE 8 1 -(2-(N-(5-Nitropyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) ethyl)-3-(3-(1 H-imidazol-4- yl)propyl)thiourea In a similar manner as described for the synthesis of N-1-(5-bromopyrid-2-yl)-1-(3,4- dichlorobenzyl)ethane-1 ,2-diamine, sodium hydride (0.692 g, 17.3 mmol), N-1-(5- nitropyrid-2-yl)ethane-1 ,2-diamine (3.00 g, 16.5 mmol), and 3,4-dichlorobenzyl chloride (3.22 g, 16.5 mmol) in DMSO (25 mL) gave an oil. Flash chromatography on silica gel using EtOAc 60: CH 3 OH 40: concentrated NH 4 OH 1 as the solvent yielded 2.84 g (51%) of N-1-(5-nitropyrid-2-yl)-1-(3,4-dichlorobenzyl)ethane-1,2-diamine as an oil. 1 H NMR (90 MHz CDCI 3 )d 1.35 (br s, 2 H, NH 2 ), 3.68 (t, 2 H), 4.88 (s, 2 H) 6.55 (d, J = 9.6 Hz, 1 H, pyridine H-3), 7.30 (m, 3 H), 8.23 (dd, J = 2.7 Hz, 9.3 Hz, 1 H, pyridine H-4), 9.08 (d, J = 2.9 Hz, 1 H, pyridine H-6). 13 C NMR (90 MHz CDCI 3 )d 39.71 , 51.74, 52.12, 104.61 , 126.23, 128.83, 130.83, 133.11 , 137.33, 146.49. Using a similar procedure as described for the synthesis of 2-[N-(5-bromopyrid-2-yl)- N-(3,4-dichlorobenzyl)]aminoethyl isothiocyanate, DCC (1.70 g, 8.21 mmol), carbon disulfide (6.70 g, 88 mmol), and N-1-(5-nitropyrid-2-yl)-1-(3,4-dichlorobenzyl) ethane- 1 ,2-diamine (2.80 g, 8.21 mmol) in THF (60 mL) gave a dark yellow solid. Flash chromatography on silica gel using hexane 50: CH 2 CI 2 50: Et 3 N 1 as the solvent system gave 2.20 g (71%) of 2-[N-(3,4-dichlorobenzyl)-N-(5-nitropyrid-2- yl)]aminoethyl isothiocyanate as a yellow solid. mp 104-106 °C 1 H NMR d 3.94 (m, 4 H), 4.85 (s, 2 H, ArCH 2 ), 6.49 (d, J = 10 Hz, 1 H, pyridine H-3), 7.29 (m, 3 H, ArH), 8.23 (dd, J = 2.7 Hz, 9.3 Hz, 1 H, pyridine H-4), 9.08 (d, J = 2 Hz, 1 H, pyridine H-6). Anal. Calcd for C 15 H l2 CI 2 N 4 O 2 S: C, 47.01 ; H, 3.16; N, 14.62. Found: C, 46.93; H, 3.32; N, 14.56. A suspension of 3-[1-(triphenylmethyl)imidazol-4-yl)propylamine (959 mg, 2.61 mmol) in THF (20 mL) was cooled to 0-5 °C in an ice-water bath and treated dropwise with 2-[N-(3,4-dichloro benzyl)-N-(5-nitropyrid-2-yl)]aminoethyl isothiocyanate (1.00 g, 2.61 mmol) in THF (40 mL). After stirring overnight at room temperature under a nitrogen atmosphere, the solvent was removed under reduced pressure to yield 2.1 g of a yellow foam. The intermediate trityl-protected thiourea was suspended in 1 N HCI (35 mL) and refluxed for 1.5 h. The solution was filtered, extracted with diethyl ether (2 x 200 mL), basified with 6 N NaOH, and extracted with EtOAc (3 x 100 mL). The combined ethyl acetate extracts were washed with water (3 x 100 mL), dried (Na2SO4), and evaporated under vacuum to yield a foam. Flash chromatography on silica gel using a solvent system of CH 2 CI 2 90: CH 3 OH 10:concentrated NH 4 OH 1 yielded 500 mg (38%) of the title compound as a yellow foam. 1 H NMR (DMSO-d 6 ) d 1.72 (m, 2 H), 3.50 (m, 8 H), 4.93 (s, 2 H, ArCH 2 ), 6.75 (s, 1 H), 7.35 (m, 7 H), 8.22 (dd, 1 H, pyridine H-4), 8.97 (d, J = 2.7 Hz, pyridine H-6). 13 C NMR (90 MHz CDCI 3 )d 23.14, 28.99, 42.05, 42.40, 48.01 , 51.58, 105.27, 126.45, 128.89, 130.89, 133.17, 133.98, 146.28, 160.58, 181.46. Anal. Calcd for C 21 H 23 CI 2 N 7 O 2 S: C, 49.60; H, 4.57; N, 19.29. Found: C, 49.89; H, 4.86; N, 18.86. EXAMPLE 9 1 -(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) ethyl)-3-(3-(pyrrolidin-1 ■ yl)propyl)thiourea A solution of N-(3-aminopropyl)pyrrolidine (354 mg, 2.76 mmol) in THF (50 mL) was cooled to 0-5 °C in an ice-water bath under a nitrogen atmosphere and treated with 2-[N-(3,4-dichlorobenzyl)-N-(5-nitropyrid-2-yl)]aminoethyl isothiocyanate (1.19 g, 2.76 mmol) in THF (25 mL). The reaction mixture was allowed to warm to room temperature and was stirred overnight. Removal of the solvent under reduced pressure afforded an oil which solidified upon trituration with hexane-EtOAc. Recrystallization from EtOAc-hexane afforded 1.03 g (66%) of the title compound as a white solid. mp 123-125 °C. 1 H NMR (90 MHz CDCI 3 )d 1.77 (m, 6 H), 2.45 (m, 6 H), 3.50 (m, 6H), 4.68 (s, 2 H, ArH), 6.50 (d, 1 H), 7.00-7.55 (m, 6 H), 8.16 (d, J = 2.2 Hz, 1 H). 13 C NMR (90 MHz CDCI 3 )d 23.62, 28.17, 43.07, 47.89, 51.74, 107.59, 108.08, 126.33, 128.83, 130.94, 138.47, 140.26, 148.55, 156.84, 183.0. Anal. Calcd for C 22 H 28 BrCI 2 N 5 S: C, 48.44; H, 5.18; N, 12.84. Found: C, 48.40; H, 5.26; N, 12.77. EXAMPLE 10 1-(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) ethyl)-3-(3- dimethylaminopropyl)thiourea A solution of N-1-(5-bromopyrid-2-yl)-1-(3,4-dichlorobenzyl)ethane-1 ,2-diamine (1.00 g, 2.67 mmol) in THF (25 mL) was cooled to 0-5 °C under a nitrogen atmosphere and treated dropwise with a solution of 3-(dimethylamino)propyl isothiocyanate (385 mg, 2.67 mmol) in THF (15 mL). After stirring overnight at room temperature, the solvent was removed under reduced pressure to afford an oil. Flash chromatography on silica gel using a solvent system of EtOAc 85: CH 3 OH 15: concentrated NH 4 OH 1 gave 900 mg (65%) of the title compound as a white foam. Η NMR (90 MHz CDCI 3 )d 1.70 (9m, 2 H), 1.95-2.45 (m, including a singlet at 2.23 N(CH 3 ) 2 , 8 H), 2.50-3.95 (m, 6 H), 4.68 (s, 2 H, ArCH 2 ), 6.47 (d, J = 9 Hz, 1 H), 7.20 (m, 6 H), 7.55 (d, J = 2.2 Hz, 1 H), 8.18 (d, J = 2.5 Hz, 1 H). 13 C NMR (90 MHz CDCI 3 )d 26.32, 43.11 , 44.85, 47.67, 51.52, 57.28, 107.97, 126.06, 128.55, 130.77, 131.26, 132.89, 138.09, 140.15, 148.33, 156.72, 182.46. EXAMPLE 11 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(imidazol-1- yl)propyl)thiourea dihydrobromide Following the method for the synthesis of N-1 -(5-bromopyrid-2-yl)ethane-1 ,2-diamine, 2-bromopyridine (20.0 g, 126.7 mmol), pyridine (12.7 g, 160.8 mmol), and 1 ,3- diaminopropane (47.4 g, 639 mmol) afforded a dark brown oil. Vacuum distillation gave 9.19 g (48 %) of a N-1 -(pyrid-yl)propane-l ,3-diamine as a light yellow oil. bp 111-114 °C (0.65 mm). 1 H NMR (90 MHz CDCI 3 )d 1.28 (br s, 2 H, NH 2 ), 1.75 (m, 2 H), 2.84 (t, 2 H), 3.35 (m, 2 H), 5.00 (br s, 2 H, NH), 6.50 (m, 2 H), 7.40 (ddd, 1 H), 8.07 (m, 1 H). 13 C NMR (90 MHz CDCI 3 )d 32.93, 39.92 (2X), 106.77, 112.30, 137.17, 148.00, 159.00. Following the procedure described for the synthesis of N-1-(5-bromopyrid-2-yl)-1- (3,4-dichlorobenzyl)ethane-1 ,2-diamine, N-1-(pyrid-yl)propane-1 ,3-diamine (5.00 g, 33.1 mmol), sodium hydride as a 60 % mineral oil dispersion (1.39 g, 34.8 mmol), and 4-bromobenzyl bromide (8.27 g, 33.1 mmol) in DMSO (50 mL) gave a yellow oil. Flash chromatography on silica gel using CH 2 CI 2 90: CH 3 OH 5: Et 3 N 5 as the solvent system afforded 2.28 g (22 %) of N-1-(4-bromobenzyl)-1-(pyrid-2-yl)propane-1,3- diamine as a light yellow oil. Η NMR (90 MHz CDCI 3 )d 1.75 (m, 4 H, CH 2 and NH 2 ), 2.72 (t, 2 H), 3.59 (t, 2 H, NCH 2 ), 4.72 (s, 2 H, ArCH 2 ), 6.38-7.00 (m, 7 H, ArH), 8.16 (d, 1 H, pyridine H-6). 13 C NMR (90 MHz CDCI 3 )d 31.21, 39.50, 45.73, 50.98, 105.81 , 112.04, 120.60, 128.62, 131.65, 137.34, 137.93, 148.07, 158.20. A solution of N-1-(4-bromobenzyl)-1-(pyrid-2-yl)propane-1 ,3-diamine (616 mg, 1.92 mmol) in THF (15 mL) was treated dropwise with 3-(imidazol-1-yl)propyl isothiocyanate (323 mg, 1.92 mmol) in THF (10 mL) under a nitrogen atmosphere. After stirring overnight at room temperature, the solid was filtered. Evaporation of the filtrate under reduced pressure gave a yellow oil which was dissolved in methanol and acidified with methanolic hydrogen bromide. Addition of diethyl ether afforded a cloudy solution which produced a light tan solid upon standing in the refrigerator. The solid was filtered and dried to yield 0.94 g (75%) of the title compound. Recrystallization from absolute ethanol-diethyl ether afforded an analytical sample. mp 199-201 °C. 1 H NMR (DMSO-d 6 ) d 1.55-2.25 (m, 4 H, CH2), 3.20-3.90 (m, 6 H, CH 2 ), 4.26 (t, 2 H, CH 2 -imidazole), 7.00 (t, 1 H), 7.26 (d, J = 8.3 Hz, 2 H, 2,6 H of C 6 H 4 -4-Br), 7.57 (d, J = 8.3 Hz, 3,5 H of C 6 H 4 -4-Br), 7.86 (m, 9 H). 13 C NMR (DMSO-d6) d 25.57, 29.09, 37.87, 39.98, 46.10, 47.40, 51.57, 111.76, 112.20, 121.78, 131.37, 134.73, 135.11 , 137.44, 143.40, 151.27, 181.66. Anal. Calcd for C 22 H 29 Br 3 N e S: C, 40.69; H, 4.51; N, 12.95. Found: C, 39.96; H, 4.52; N, 12.65. EXAMPLE 12 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(4-(N-(pyridin-2- yl)amino)propyl)thiourea Following the method for the synthesis of N-1-(5-bromopyrid-2-yl)ethane-1 ,2-diamine, 2-bromopyridine (20.0 g, 126.7 mmol), pyridine (12.7 g, 160.8 mmol), and 1 ,3- diaminopropane (47.4 g, 639 mmol) afforded a dark brown oil. Vacuum distillation gave 9.19 g (48 %) of a N-1-(pyrid-yl)propane-1 ,3-diamine as a light yellow oil. bp 111-114 °C (0.65 mm). 1 H NMR (90 MHz CDCI 3 )d 1.28 (br s, 2 H, NH 2 ), 1.75 (m, 2 H), 2.84 (t, 2 H), 3.35 (m, 2 H), 5.00 (br s, 2 H, NH), 6.50 (m, 2 H), 7.40 (ddd, 1 H), 8.07 (m, 1 H). 13 C NMR (90 MHz CDCI 3 )d 32.93, 39.92 (2X), 106.77, 112.30, 137.17, 148.00, 159.00. A solution of N-1-(pyridyl)propane-1 ,3-diamine (419 mg, 2.76 mmol) in THF (25 mL) was cooled to 0-5 °C under a nitrogen atmosphere and treated dropwise with 3-[N-(4- bromobenzyl)-N-(pyrid-2-yl)]aminopropyl isothiocyanate (1.00 g, 2.76 mmol) in THF (10mL). After stirring overnight at room temperature, the solvent was removed under reduced pressure to afford an oil. The oil was flash chromatographed on silica gel using a solvent system of CH 2 CI 2 90: CH 3 OH 5: Et 3 N 5 to yield 9, 50 mL fractions. Fractions 3-9 were combined and the solvents were removed under reduced pressure to give 1.31 g (92%) of the title compound as an oil (Rf = 0.5). Η NMR (90 MHz CDCI 3 )d 1.82-2.40 m, 7 H), 3.58 (m, 5 H), 4.57 (s, 2 H, ArCH 2 ), 4.75 (br m, NH), 6.35-8.14 (m, 14 H). 13 C NMR (90 MHz CDCI 3 )d 27.14, 29.53, 38.63, 41.17, 45.34, 51.30, 106.40, 108.29, 112.52, 112.85, 120.86, 128.18, 131.81 , 136.68, 137.39, 137.77, 147.63, 158.73, 181.05. MS (CI, CH 4 ) m/z 513 (M + ). Anal. Calcd for C 24 H 29 BrN 6 S: C, 56.14; H, 5.69; N, 16.37. Found: C, 56.10; H, 5.73; N, 16.34. EXAMPLE 13 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) propyl)-3-(3-(imidazol-1- yl)propyl)thiourea Following the method described for the synthesis of N-1-(5-bromopyrid-2-yl)-1-(3,4- dichlorobenzyl)ethane-1 ,2-diamine, N-1-(5-bromopyrid-yl)propane-1 ,3-diamine (5.00 g, 21.7 mmol), a 60% mineral oil suspension of of sodium hydride (0.914 g, 22.9 mmol), and 3,4-dichlorobenzyl chloride (4.25 g, 21.7 mmol) in DMSO (45 mL) gave an oil. Flash chromatography on silica gel using CH 2 CI 2 90: CH 3 OH 5:Et 3 N 5 as the solvent yielded 4.92 g (58%) of the N-1 -(5-bromopyrid-2-yl)-1 -(3,4-dichlorobenzyl) propane-1 , 3-diamine as an oil. Η NMR (90 MHz CDCI 3 )d 1.44 (s, 2 H, NH 2 ), 1.80 (m, 2 H), 2.73 (t, 2 H), 3.56 (t, 2 H), 4.66 (s, 2 H, ArCH 2 ), 6.37 (d, J = 9 Hz, 1 H, pyridine H-3), 7.31 (m, 4 H), 8.15 (d, J = 2.5 Hz, 1 H, pyridine H-6). 13 C NMR (90 MHz CDCI 3 )d 30.93, 39.44, 46.21 , 50.71 , 106.67, 107.16, 126.23, 128.72, 130.51 , 130.89, 132.62, 138.90, 139.66, 148.55, 156.46. A solution of N-1-(5-bromopyrid-2-yl)-1-(3,4-dichloro benzyl)propane-1 , 3-diamine (1.00 g, 2.57 mmol) in THF was cooled to 0-5 °C under a nitrogen atmosphere and treated dropwise with 3-(1-imidazolyl)propyl isothiocyanate (432 mg, 2.57 mmol) in THF (15 mL). The reaction mixture was allowed to warm to room temperature and was stirred overnight. Removal of the solvent under reduced pressure afforded a semisolid. Trituration with diethyl ether-petroleum ether gave a solid which was recrystallized from ethyl acetate-diethyl ether to yield 450 mg (31 %) of the title compound. mp 94-97 °C (decomposition). 1 H NMR (90 MHz CDCI 3 )d 1.60-2.35 (m, 4 H), 3.54 (m, 5 H), 4.05 (t, 2 H, CH 2 - imidazole) 4.57 (s, 2 H, ArCH 2 ), 6.28 (d, J = 9 Hz, 1 H), 6.99 (d, J = 4.4 Hz, 1 H), 7.19 ( m, 9 H). 13 C NMR (90 MHz CDCI 3 )d 27.03, 30.91 , 41.01 , 41.50, 44.59, 45.94, 51.03, 107.05, 107.64, 119.18, 125.90, 128.39, 129.21 , 130.78, 131.21 , 132.89, 136.95, 137.98, 140.04, 148.33, 156.62, 182.62. Anal. Calcd for C 22 H 25 BrCI 2 N 6 S: C, 47.49; H, 4.53; N, 15.11. Found: C, 47.23; H, 4.59; N, 14.98. EXAMPLE 14 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) propyl)-3-(4-(N-(pyridin-2- yl)amino)propyl)thiourea Using the general method, DCC (1.94 g, 9.35 mmol), carbon disulfide (7.62 g, 100 mmol), and N-1-(5-bromopyrid-2-yl)-1-(3,4-dichlorobenzyl)propane-1 ,3-diamine (3.64 g, 9.35 mmol) in THF (45 mL) gave an oil. Purification by flash chromatography on silica gel using hexane 70: EtOAc 30:Et 3 N 1 as the solvent afforded 3.19 g (79%) of 3-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)]aminopropyl isothiocyanate as an oil. 1 H NMR (90 MHz CDCI 3 )d 2.06 (m, 2 H), 3.62 (m, 4 H), 4.66 (s, 2 H, ArCH 2 ), 6.40 (m, 1 H), 7.35 (m, 4 H), 8.22 (m, 1 H). 13 C NMR d 28.06, 42.91 , 46.10, 51.41 , 107.21 , 107.43, 126.17, 128.72, 130.72, 131.26, 138.31 , 139.93, 148.76, 156.13. MS (CI, CH 4 ) 432 M + . Anal. Calcd for C 18 H 14 BrCI 2 N 3 S: C, 44.56; H, 3.28; N, 9.75. Found: C, 44.39; H, 3.42; N, 9.79. A solution of N-1-(4-bromobenzyl)-1-(pyrid-2-yl)propane-1 ,3-diamine (352 mg, 2.32 mmol) in THF (30 mL) was cooled to 0-5 °C under nitrogen and treated dropwise with of 3-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)]aminopropyl isothiocyanate (1.00 g, 2.32 mmol) in THF (20 mL). After stirring at room temperature overnight, the solvent was removed under reduced pressure to afford an oil. Flash chromatography on silica gel using a solvent system of CH 2 CI 2 98: CH 3 OH 1 : Et 3 N 1 gave the title compound as an oil which solidified upon trituration with hexane. Recrystallization from ethyl acetate-hexane gave a hygroscopic solid. mp 88 °C (decomposition); Η NMR (90 MHz CDCI 3 )d 0.90-2.10 (m, 4 H), 3.50 (m, 8 H), 4.57 (s, 2 H, ArCH 2 ), 4.90 (br s, 1 H, NH), 6.30 (d, J = 9.3 Hz, 1 H, pyridine H-3), 6.45-8.18 (m, 11 H, ArH and NHC=SNH); 13 C NMR (90 MHz CDCI 3 )d 27.09, 29.64, 38.63, 41.34, 41.45, 46.05, 51.14, 107.16, 107.65, 108.57, 112.90, 125.99, 128.51 , 130.78, 131.21 , 132.89, 137.55, 138.15, 140.10, 147.30, 148.50, 156.62, 158.79, 181.43; MS (Cl, CH 4 ) m/z 583 (M + ). Anal. Calcd for C 24 H 27 BrCI 2 N 6 S: C, 49.50; H, 4.67; N, 14.43. Found: C, 49.28; H, 4.57; N, 14.21. EXAMPLE 15 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) propyl)-3-(3-(1H-imidazol- 4-yl)propyl)thiourea A suspension of 3-[1-(triphenylmethyl)imidazol-4-yl] propylamine (1.32 g, 3.60 mmol) in THF (50 mL) was treated dropwise with of 3-[N-(5-bromopyrid-2-yl)-N-(3,4-dichloro benzyl)]aminopropyl isothiocyanate (1.55 g, 3.60 mmol) in THF (25 mL) at 0-5 °C under a nitrogen atmosphere. The reaction mixture was allowed to warm to room temperature and was stirred overnight. Removal of the solvent under reduced pressure afforded an oil. Flash chromatography on silica gel using a solvent system of EtOAc 92: CH 3 OH 4: Et 3 N 4 gave 2.10 g (73%) of the trityl-protected thiourea. The oil was suspended in 2 N HCI (50 mL) and was refluxed for 7 h. The precipitated triphenylmethanol was filtered, and the aqueous acid was evaporated under reduced pressure to yield a foam. The hygroscopic hydrochloride was converted to the free base with 1 N NaOH, and the aqueous layer was extracted with EtOAc (3 x 75 mL). The combined extracts were washed with water (2 x 50 mL), dried (Na 2 SO 4 ), filtered, and evaporated to afford 600 mg of a foam. Purification by flash chromatography on silica gel using EtOAc 85: CH 3 OH 15: concentrated NH 4 OH 1 as the solvent system gave 533 mg (27%) of the title compound as a solid foam. 1 H NMR (90 MHz CDCI 3 )d 2.05 (m, 4 H), 2.70 (m, 2 H), 3.59 (m, 6 H), 4.59 (s, 2 H, ArCH 2 ), 6.30 (d, J = 9.3 Hz, 1 H), 6.50-8.11 (m, 9 H); 13 C NMR (90 MHz CDCI 3 )d 23.73, 27.03, 28.82, 41.88, 43.29, 46.10, 106.99, 107.70, 115.93, 126.01 , 128.50, 130.72, 131.10, 132.78, 134.41 , 137.39, 138.20, 140.04, 148.33, 156.56, 181.38. Anal. Calcd. for C 22 H 25 BrCI 2 N 6 S: C, 47.49; H, 4.54; N, 15.11. Found: C, 47.48; H, 4.48; N, 14.96. EXAMPLE 16 1-(3-(N-(5-Bromopyridin-2-yl)-N-((naphth-1-yl)methyl)amino)propyl)-3-(3-(1 H- imidazol-4-yl)propyl)thiourea According to the method for the synthesis of N-1 -(5-bromopyrid-2-yl)ethane-1 ,2- diamine, 2,5-dibromopyridine (4.40 g, 18.6 mmol), pyridine (1.86 g, 23.6 mmol), and 1 ,3-diaminopropane (25 mL) yielded an oil. Vacuum distillation afforded 2.69 g (63%) of N-1 -(5-bromopyrid-yl)propane-1 , 3-diamine as an oil. bp 135-139 °C (0.1 mm); 1 H NMR (90 MHz CDCI 3 )d 1.52 (br s, 2 H, NH 2 ), 1.72 (m, 2 H), 2.89 (t, 2 H), 3.36 (m, 2 H), 5.30 (br s, 1 H, NH), 6.29 (d, J = 9 Hz, 1 H, pyridine H-3), 7.44 (dd, J = 2.4 Hz, J = 8.8 Hz, 1 H, pyridine H-4), 8.09 (d, J = 2.4 Hz, 1 H, pyridine H-6); 13 C NMR (90 MHz CDCI 3 )d 32.61 , 39.98, 40.25, 106.45, 108.29, 139.50, 148.49, 157.48. N-[1-(5-bromopyrid-2-yl)-1-(naphthal-1-yl)methyl]propane-1 , 3-diamine (3e). Using the method described for the synthesis of N-1-(5-bromopyrid-2-yl)-1-(3,4- dichlorobenzyl)ethane-1,2-diamine, N-1-(5-bromopyrid-yl)propane-1 ,3-diamine (8.71 g, 37.9 mmol), a 60 % mineral oil dispersion of sodium hydride (1.67 g, 41.6 mmol), and 1-(bromomethyl)naphthalene (9.21 g, 41.6 mmol) in DMSO (60 mL) gave an oil. Flash chromatography on silica gel using CH 2 CI 2 50: CH 3 OH 50: concentrated ammonium hydroxide 1 afforded 5.10 g (35 %) of N-[1-(5-bromopyrid-2-yl)-1- (naphthal-1-yl)methyl]propane-1 ,3-diamine as an oil. 1 H NMR (90 MHz CDCI 3 )d 1.43 (br s, 2 H, NH 2 ), 1.75 (m, 2 H), 3.67 (t, 2 H), 5.12 (s, 2 H, CH 2 -a-naphthalylmethyl) 6.31 (d, J = 9 Hz, 1 H, pyridine H-3), 7.15-8.05 (m, 8 H, ArH), 8.20 (d, J = 2.4 Hz, 1 H, pyridine H-6); 13 C NMR (90 MHz CDCI 3 )d 31.31, 39.55, 45.72, 49.62, 106.29, 107.54, 122.76, 123.84, 125.47, 125.85, 126.23, 127.74, 128.94, 131.32, 132.24, 133.92, 139.55, 148.55, 156.94. Following the procedure described for the preparation of 2-[N-(5-bromopyrid-2-yl)-N- (3,4-dichloro benzyl)]aminoethyl isothiocyanate, DCC (2.32 g, 10.8 mmol), carbon disulfide (8.80 g, 115 mmol) and N-[1-(5-bromopyrid-2-yl)-1-(naphthal-1- yl)methyl]propane-1 , 3-diamine (4.00 g, 10.8 mmol) in THF (140 mL) afforded an oil. Flash chromatography on silica gel using a solvent system of hexane 50: CH 2 CI 2 50: Et 3 N 1 gave 2.70 g (84 %) of 3-[N-(5-bromopyrid-2-yl)-N-(naphthal-1- yl)methyl]aminopropyl isothiocyanate as a colorless oil. 1 H NMR (90 MHz CDCI 3 )d 2.00 (m, 2 H, NCH 2 CH 2 CH 2 N=C), 3.54 (t, 2 H), 3.74 (t, 2H), 5.11 (s, 2 H, ArCH 2 ), 6.30 (d, J = 9 Hz, 1 H, pyridine H-3), 7.15-8.02 (m, 8 H, ArH), 8.25 (d, J = 2.4 Hz, 1 H, pyridine H-6); 13 C NMR d 28.28, 43.01 , 45.77, 50.32, 106.99, 107.59, 122.65, 123.89, 125.41 , 125.90, 126.39, 127.96, 128.93, 139.71 , 148.60, 156.62. A solution of 3-[1-(triphenylmethyl)imidazol-4-yl)propylamine (1.24 g, 3.38 mmol) was dissolved in THF (20 mL) and treated dropwise with a solution of 3-[N-(5-bromopyrid- 2-yl)-N-(naphthal-1-yl)methyl] aminopropyl isothiocyanate (1.40 g, 3.38 mmol) in THF (20 mL) at 0-5 °C under a nitrogen atmosphere. The reaction mixture was allowed to warm to room temperature and was stirred overnight. The solvent was evaporated under reduced pressure to yield an oil which was purified by flash chromatography on silica gel using a solvent system of EtOAc 92: CH 3 OH 4: Et 3 N 4. Fractions homogeneous on TLC were combined and evaporated to give 2.63 g of the trityl- protected thiourea. The oil was suspended in 1 N HCI (60 mL) and refluxed for 1.5 h. The precipitate was filtered, and the filtrate was extracted with diethyl ether (2 x 100 mL). The aqueous layer was basified with 6 N NaOH and extracted with ethyl acetate (3 x 100 mL). The combined ethyl acetate extracts were washed with water (2 x 50 mL), dried (Na 2 SO 4 ), filtered, and evaporated to yield an oil. Flash chromatography on silica gel using an eluent of CH 2 CI 2 90: CH 3 OH 10: concentrated NH 4 OH 1 afforded 1.10 g (61 %) of the title compound as a foam. 1 H NMR (90 MHz CDCI 3 )d 1.88 (m, 4 H), 2.65 (m, 2 H), 3.30-3.80 (m, 6 H), 5.02 (s, 2 H, 1-naphthalyl-CH 2 ), 6.18-8.11 (m, 14 H, ArH and NHC=SNH); 13 C (90 MHz CDCI 3 )d 24.06, 27.19, 29.38, 42.20, 43.75, 50.94, 108.44, 115.63, 122.50, 123.44, 125.31 , 125.94, 126.56, 128.13, 129.38, 131.56, 134.75, 135.00, 138.75, 140.63, 148.44, 157.81 , 181.56. Anal. Calcd for C 2β H 29 BrN β S: C, 58.09; H, 5.45; N, 15.64. Found: C, 57.72; H, 5.62; N, 15.61. EXAMPLE 17 1 -(4-Aminobutyl)-3-(3-(N-(5-bromopyridin-2-yl)-N-((naphth-1 - yl)methyl)amino)propyl)thiourea A solution of (4-phthalimido butyl)amine hydrochloride (688 mg, 2.7 mmol) and triethylamine (547 mg, 5.4 mmol) in THF (25 mL) was stirred for 2 h at room temperature. The reaction mixture was treated dropwise with a solution of 3-[N-(5- bromopyrid-2-yl)-N-(naphthal-1-yl)methyl] aminopropyl isothiocyanate (1114 mg, 2.7 mmol) in THF (20 mL), and the mixture was stirred overnight under nitrogen. The precipitated triethylamine hydrochloride was filtered, and the filtrate was evaporated under reduced pressure to afford an oil. Purification by flash chromatography on silica gel using a solvent system of CH 2 CI 2 100: CH 3 OH 2: concentrated NH 4 OH 1 gave 1.08 g of a yellow foam. The foam was suspended in a mixture of ethanol (20 mL) and 85% hydrazine hydrate (641 mg, 12.7 mmol), and the mixture was refluxed for 5 h. The mixture was filtered to remove the precipitated phthalhydrazide, and the solvent was removed under reduced pressure to yield an oily residue. The oil was dissolved in CH 2 CI 2 (75 mL), washed with water (3 x 50 mL), separated, dried (Na 2 SO 4 ), filtered, and evaporated to yield 700 mg of the amine as a light yellow foam. Flash chromatography on silica gel using EtOAc 50: CH 3 OH 50: concentrated NH 4 OH 1 as the solvent yielded 650 (48%) of the title compound as a white foam. 1 H NMR (90 MHz CDCI 3 )d 1.70 (m, 10 H), 2.79 (m, 2 H), 3.70 (m, 6 H), 5.06 (s, 2 H, ArCH 2 ), 6.29 (d, 9 Hz, 1 H), 6.70-8.20 (m, 11 H); 13 C NMR (90 MHz CDCI 3 )d 26.32, 27.18, 30.27, 41.43, 41.59, 43.71 , 45,39, 49.83, 106.66, 108.34, 122.37, 123.07, 125.45, 126.00, 126.43, 127.95, 129.03, 130.82, 131.03, 133.86, 140.08, 147.99, 157.47, 181.03. EXAMPLE 18 1-(4-Aminobutyl)-3-[3-[N-(5-bromopyrid-2-yl)]-[N-(3,4- dichlorobenzyl)]aminopropyl]thiourea A suspension of (4-phthalimidobutyl)amine hydrochloride (1.50 g, 5.89 mmol) and triethylamine (1.49 g, 14.7 mmol) was stirred under nitrogen for 3 h at room temperature, and a solution of 3-[N-(5-bromopyrid-2-yl)-N-(3,4- dichlorobenzyl)]aminopropyl isothiocyanate (2.54 g, 5.89 mmol) in THF (50 mL) was added dropwise. After stirring overnight, the precipitate was filtered and the filtrate was evaporated under reduced pressure to yield an oil. Flash chromatography on silica gel using CH 2 CI 2 100: CH 3 OH 1 xoncentrated ammonium hydroxide 1.5 as the solvent afforded 2.06 g of the intermediate phthalimide as an oil. The oil was dissolved in a mixture of 85% hydrazine hydrate (635 mg, 12.7 mmol) and absolute ethanol (75 mL) and refluxed for 8 h. The reaction mixture was cooled, filtered, and evaporated to yield an oil. Absolute ethanol (25 mL) was added and the solution was concentrated under reduced pressure. The resulting residue was partitioned between diethyl ether (200 mL) and water (50 mL), and the diethyl ether phase was separated, dried (Na 2 SO 4 ), filtered, and evaporated under reduced pressure. Flash chromatography on silica gel using EtOAc 50: CH 3 OH 50: concentrated NH 4 OH 1.2 afforded 1.15 g (70%) the title compound as a colorless oil. 1 H NMR (90 MHz CDCI 3 )d 1.66 (m, 6 H, CH 2 and NH 2 ), 2.80 (t, 2 H), 3.59 (m, 6 H), 4.62 (s, 2 H, ArCH 2 ), 6.35 (d, J = 9 Hz, 1 H, pyridine H-3), 6.99-7.56 (m, 6 H, ArH and NHC=SNH), 8.18 (d, J = 2.4 Hz, 1 H, pyridine H-6) 13 C NMR d 26.33, 27.09, 30.28, 41.44, 41.61 , 43.83, 50.98, 107.75, 125.90, 128.39, 130.78, 137.87, 140.15, 148.28, 156.78, 181.11. Anal. Calcd. for C 20 H 26 BrCI 2 N 5 S: C, 42.26; H, 5.05; N, 13.49. Found: C, 46.09; H, 5.10; N, 12.90. EXAMPLE 19 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) propyl)-3-(3-(pyrrolidin-1- yl)propyl)thiourea A solution of N-(3-aminopropyl)pyrrolidine (354 mg, 2.76 mmol) in THF (50 mL) was cooled to 0-5 °C under a nitrogen atmosphere and treated dropwise with a solution of 3-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)]aminopropyl isothiocyanate (1.19 g, 2.76 mmol) in THF (25 mL). The reaction mixture was allowed to warm to room temperature and was stirred overnight. The solvent was removed under reduced pressure to afford an oil which solidified upon trituration with hexane-ethyl acetate. Recrystallization form ethyl acetate-hexane gave 1.03 g (66%) of the title compound as a white solid. mp 122-124 °C; 1 H NMR (90 MHz CDCI 3 )d 1.73 (m, 8 H), 2.57 (m, 6 H), 3.60 (m, 6 H), 4.63 (s, 2 H, ArCH 2 ), 6.33 (d, J = 9 Hz, 1 H, pyridine H-3), 7.00-7.53 (m, 6 H, ArH and NHC=SNH), 8.18 (d, J = 2.4 Hz, 1 H, pyridine H-6); 13 C NMR (90 MHz CDCI 3 )d 23.46, 27.14, 41.99, 46.16, 51.09, 53.36, 53.69, 107.05, 107.48, 126.12, 128.61 , 130.72, 132.72, 132.84, 138.31 , 139.99, 148.55, 156.51 , 182.13. Anal. Calcd. for C 23 H 30 BrCI 2 N 5 S: C, 49.39; H, 5.41 ; N, 12.52. Found: C, 49.14; H, 5.44; N, 12.45 EXAMPLE 20 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) propyl)-3-(2-(pyrid-2- yl)ethyl)thiourea A solution of 2-(2-aminoethyl)pyridine (0.33 g, 2.71 mmol) in THF (50 mL) was cooled to 0-5 °C under a nitrogen atomosphere and treated with a solution of 3-[N-(5- bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)]aminopropyl isothiocyanate (1.17 g, 2.71 mmol) in THF (25 mL). The reaction mixture was allowed to warm to room temperature and was stirred overnight. Removal of the solvent under reduced pressure afforded an oil which was purified by flash chromatography on silica gel using EtOAc 96: CH 3 OH 4: concentrated NH 4 OH 1 as the solvent system. Fractions homogeneous by TLC were combined and evaporated to yield 1.11 g (74%) of the title compound as a foam. 1 H NMR (90 MHz CDCI 3 )d 1.78 (m, 2 H), 3.00 (t, 2 H), 3.69 (m, 6 H), 4.59 (s, 2 H, ArH), 6.30 (d, J = 9 Hz, 1 H, pyridine H-3), 6.88-8.49 (m, 11 H, ArH and NHC=SNH); 13 C NMR (90 MHz CDCI 3 ) d 26.82, 36.30, 41.34, 43.34, 45.89, 50.93, 107.05, 107.59, 121.84, 123.63, 125.91 , 128.40, 130.67, 131.11 , 132.79, 136.96, 137.99, 139.99, 148.50, 148.93, 156.57, 159.06, 181.11. Anal. Calcd. for C 23 H 24 BrCI 2 N 5 S: C, 49.93; H, 4.37; N, 12.66. Found: C, 49.81 ; H, 4.43; N, 12.42. EXAMPLE 21 1-(4-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)butyl)-3-(3-(imidazol-1- yl)propyl)thiourea Following the general method described for N-1-(5-bromopyrid-2-yl)ethane-1 ,2- diamine, 2-bromopyridine (20.0 g, 126.7 mmol), 1,4-diaminobutane (56.3 g, 639 mmol), and pyridine (12.7 g, 160.8 mmol) gave 11.5 g (55%) of N-1-(pyrid-2- yl)butane-1 ,4-diamine as a light yellow oil. bp 103-105 °C (0.05 mm); Η NMR (90 MHz CDCI 3 )d 1.56 (br s, 2 H, NH 2 ), 1.61 (m, 4 H), 2.73 (t, 2 H), 3.25 (m, 2 H), 4.73 (br s, 1 H, NH), 6.43 (m, 2 H), 7.40 (ddd, 1 H), 8.08 (m, 1 H); 13 C NMR(90 MHz CDCI 3 ) d 27.03, 31.25, 41.98, 42.09, 106.56, 112.57, 137.27, 148.22, 159.00. In a similar manner as described for the preparation of N-1-(5-bromopyrid-2-yl)-1- (3,4-dichlorobenzyl)ethane-1 ,2-diamine, a 60 % dispersion of sodium hydride (1.27 g, 31.8 mmol), N-1 -(pyrid-2-yl)butane-1 ,4-diamine (10.1 g, 30.3 mmol), and 4- bromobenzyl bromide (7.57 g, 30.3 mmol) in DMSO (60 mL) gave an oil. Flash chromatography on silica gel using CH 2 CI 2 90: CH 3 OH 5: Et 3 N 5 yielded 4.29 g (57%) of N-1 -(4-bromobenzyl)-1-(pyrid-2-yl)butane-1 ,4-diamine as a thick oil. Η NMR (90 MHz CDCI 3 )d 1.45 (m, 4 H, CH 2 and NH 2 ), 2.65 (t, 2 H), 3.45 (t, 2 H), 4.70 (s, 2 H, ArCH 2 ), 6.95 (m, 2 H), 7.25 (m, 5 H), 8.15 (m, 1 H); 13 C NMR (90 MHz CDCI 3 )d 24.66, 31.05, 41.94, 48.39, 50.99, 105.65, 111.88, 113.01 , 120.49, 128.67, 130.24, 130.24, 130.73, 131.49, 137.23, 138.15, 148.07, 157.93. A solution of N-1 -(4-bromobenzyl)-1-(pyrid-2-yl)butane-1 ,4-diamine (1.11 g, 3.34 mmol) in THF (30 mL) was treated dropwise with a solution of 3-(imidazol-1-yl)propyl isothiocyanate (559 mg, 3.34 mmol) in THF (10 mL). After stirring overnight at room temperature under nitrogen, the solvent was removed under reduced pressure to afford an oil. The oil was dissolved in absolute ethanol and acidified with ethanolic hydrogen chloride. Addition of diethyl ether afforded a very hygroscopic solid. The solvents were removed under reduced pressure, and the residue was partitioned between 10% NaOH (100 mL) and methylene chloride (50 mL). The basic layer was extracted with methylene chloride (2 x 50 mL), and the combined organic extracts were washed with water (2 x 50 mL), dried (Na 2 SO 4 ), filtered, and evaporated. The resulting oil was triturated with diethyl ether to yield 950 mg (57%) of a tan solid. Recrystallization from ethyl acetate-diethyl ether afforded 691 mg (41 %) the title compound. mp 122-124 °C; 1 H NMR (90 MHz CDCI 3 )d 1.63 (m, 4 H), 2.07 (m, 2 H), 3.55 (m, 6 H), 4.01 (t, J = 7.4 Hz, 2 H, CH 2 -imidazole), 4.66 (s, 2 H, ArCH 2 ), 6.36-8.18 (m, 13 H, ArH and NHC=SNH); 13 C NMR (90 MHz CDCI 3 )d 25.02, 26.16, 30.61 , 41.28, 44.09, 44.16, 48.05, 51.19, 106.02, 112.14, 119.23, 120.64, 128.50, 129.09, 131.64, 136.95, 137.49, 147.84, 157.97, 182.89. Anal. Calcd for C 23 H 29 BrN 6 S: C, 54.48; H, 5.84; N, 16.76. Found: C, 55.04; H, 5.90; N, 16.67. EXAMPLE 22 1-(4-(N-(3,4-Dichlorobenzyl)-N-(pyridin-2-yl)amino)butyl)-3-(3-(imidazol-1- yl)propyl)thiourea Following the general method, a 60 % mineral oil dispersion of sodium hydride (613 mg, 15.3 mmol), N-1-(pyrid-2-yl) butane-1 ,4-diamine (2.41 g, 14.6 mmol), and 3,4- dichloro benzyl bromide (3.50 g, 14.6 mmol) gave an oil. Purification by flash chromatography on silica gel using a solvent system of CH 2 CI 2 50: CH 3 OH 50: concentrated NH 4 OH 1 afforded 0.950 g (20%) of a light green oil. 1 H NMR (90 MHz CDCI 3 )d 1.52 (m, 4 H), 2.02 (br s, 2 H, NH 2 ), 2.70 (t, 2 H), 3.43 (t, 2 H), 4.71 (s, 2 H, ArCH 2 ), 6.50 (m, 2 H), 7.00-7.52 (m, 4 H), 8.16 (m, 1 H). A solution of N-1-(3,4-dichlorobenzyl)-1-(pyrid-2yl)butane-1 ,4-diamine (900 mg, 2.79 mmol) in THF (20 mL) was treated dropwise with 3-(imidazol-1-yl)propyl isothiocyanate (470 mg, 2.79 mmol) in THF (15 mL). After stirring overnight under nitrogen, the solvent was removed under reduced pressure. The resulting residue was flash chromatographed on silica gel using a solvent system of CH 2 CI 2 100: CH 3 OH 10: concentrated ammonium hydroxide 1 to yield a yellow foam. The foam was triturated with methanol-water to yield a white solid. Recrystallization from methylene chloride-diethyl ether afforded 659 mg (48%) of the title compound as a white, crystalline solid. mp 112-113.5 °C; 1 H NMR (90 MHz CDCI 3 )d 1.60 (m, 4 H), 2.08 (m, 2 H), 3.50 (m, 6 H), 4.00 (t, 2 H), 4.63 (s, 2 H, ArCH 2 ), 7.20 (ArH and NHC=SNH); 13 C NMR (90 MHz CDCI 3 )d 24.97, 26.17, 30.61 , 41.39, 44.10, 44.69, 48.22, 50.87, 106.02, 112.47, 126.23, 128.66, 129.21 , 130.61 , 137.71 , 139.23, 147.95, 182.95. Anal. Calcd for C 23 H 28 CI 2 N 6 S: C, 56.20; H, 5.75; N, 17.10. Found: C, 56.03; H, 5.82; N, 16.99. EXAMPLE 23 1 -(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) butyl)-3-(3-(imidazol-1 - yl)propyl)thiourea Using the method as described for the synthesis of N-1-(5-bromopyrid-2-yl)ethane- 1 ,2-diamine, 2,5-dibromopyridine (10.0 g, 42.2 mmol), 1 ,4-diaminobutane (52.6 g, 597 mmol), and dry pyridine (4.20 g, 53.2 mmol) gave a brown oil. Vacuum distillation afforded 7.87 g (76 %) of N-1 -(5-bromopyrid-2-yl)butane-1 ,4-diamine as a colorless oil. bp 165-170 °C (0.8 mm); Η NMR (90 MHz CDCI 3 )d 1.15-1.75 (m, 6 H), 2.72 (t, 2 H), 3.25 (br s, 2 H, NH 2 ), 4.75 (br s, 1 H, NH), 6.30 (d, J = 9 Hz, pyridine H-3), 7.47 (dd, J = 2.7 Hz, J = 9 Hz, 1 H, pyridine H-4), 8.10 (d, J = 2.4 Hz, pyridine H-6); 13 C NMR (90 MHz CDCI 3 )d 26.87, 31.09, 41.87, 42.20, 108.07, 139.66, 148.71. Using a similar method as described for N-1-(5-bromopyrid-2-yl)-1-(3,4- dichlorobenzyl)ethane-1 ,2-diamine, a 60% mineral oil dispersion of sodium hydride (1.20 g, 30.1 mmol), N-1 -(5-bromopyrid-2-yl)butane-1 ,4-diamine (7.00 g, 28.7 mmol), and dichlorobenzyl chloride (5.62 g, 28.7 mmol) in DMSO (75 mL) gave an oil. Flash chromatography on silica gel using a solvent system of CH 2 CI 2 50: CH 3 OH 50: concentrated NH 4 OH 1 yielded 2.32 g (20%) of N-1-(5-bromopyrid-2-yl)-1-(3,4- dichlorobenzyl)butane-1 ,4-diamine as an oil. 1 H NMR (90 MHz CDCI 3 )d 1.50 (m, 4 H, CH 2 and NH 2 ), 2.72 (t, 2 H), 3.45 (t, 2 H, NCH 2 ), 4.68 (s, 2 H, ArCH 2 ), 6.35 (d, J = 9 Hz, pyridine H-3), 7.00-7.55 (m, 4 H, ArH), 8.15 (d, J = 2.4 Hz, 1 H, pyridine H-6); 13 C NMR (90 MHz CDCI 3 )d 24.48, 30.93, 41.87, 48.81 , 59.76, 106.61 , 107.10, 126.28, 128.77, 130.45, 139.12, 139.60, 148.60, 156.29. A solution of N-1 -(5-bromopyrid-2-yl)-1 -(3,4-dichlorobenzyl) butane-1 ,4-diamine (1.01 g, 2.48 mmol) in THF (20 mL) was treated dropwise with 3-(imidazol-1-yl)propyl isothiocyanate (431 mg, 2.48 mmol) in THF (15 mL). After stirring overnight at room temperature under nitrogen, the solvent was removed under reduced pressure. The resulting residue was triturated with hexane-diethyl ether to afford a solid. Recrystallization from methylene chloride-diethyl ether gave 1.00 g (71%) the title compound as white crystals. mp 139-141 °C; Η NMR (90 MHz CDCI 3 )d 1.61 (m, 4 H), 2.07 (m, 2 H), 3.50 (m, 6 H), 4.00 (t, 2 H), 4.62 (s, 2 H, ArCH 2 ), 6.30 (d, J = 9 Hz, 1 H, pyridine H-3), 7.15 (m, 9 H), 8.12 (d, 1 H, pyridine H-6); 13 C NMR (90 MHz CDCI 3 )d 24.70, 26.33, 30.44, 41.28, 43.87, 44.64, 48.43, 50.97, 106.77, 107.32, 119.23, 126.17, 128.61 , 130.62, 130.99, 136.89, 138.74, 139.77, 148.54, 182.94. Anal. Calcd for C 23 H 27 BrCI 2 N 6 S: C, 48.42; H, 4.78; N, 14.74. Found: C, 48.24; H, 4.89; N, 14.63. EXAMPLE 24 1-(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) butyl)-3-(3-(1H-imidazol- 4-yl)propyl)thiourea A mixture of DCC (858 mg, 4.16 mmol), carbon disulfide (1.85 g, 44.2 mmol), and N- 1-(5-bromopyrid-2-yl)-1 -(3,4-dichlorobenzyl) butane-1 ,4-diamine (1.68 g, 4.16 mmol) in THF (45 mL) afforded an oil. Purification by flash chromatography on silica gel using a solvent system of hexane 80: EtOAc 20: Et 3 N 1 gave 1.53 g (83%) of 4-[N-(5- bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)] aminobutyl isothiocyanate as an oil. 1 H NMR (90 MHz CDCI 3 )d 1.72 (m, 4 H), 3.54 (m, 4 H), 4.65 (s, 2 H, ArCH 2 ), 6.32 (d, J = 9 Hz, 1 H, pyridine H-3), 6.97-7.50 (m, 4 H), 8.16 (d, J = 2.4 Hz, 1 H, pyridine H- 6); 13 C NMR (90 MHz CDCI 3 )d 24.32, 27.36, 44.80, 47.90, 51.62, 107.10, 126.18, 128.66, 130.56, 130.99, 132.67, 138.63, 139.71, 148.60, 156.18. A suspension of 3-(1-triphenylmethyl- 1 H-imidazol-4-yl)propyl amine (0.50 g, 1.51 mmol) in THF (20 mL) was treated dropwise with a solution of 4-[N-(5-bromopyrid-2- yl)-N-(3,4-dichloroben-zyl)]aminobutyl isothiocyanate (0.67 g, 1.51 mmol) in THF (10 mL) under a nitrogen atmosphere. After stirring overnight at room temperature, the solvent was removed under reduced pressure to afford an oil. Flash chromatography on silica gel using CH 2 CI 2 100: CH 3 OH 2.5:Et 3 N 2.5 afforded 0.62 g (71%) of a colorless oil. The oil was suspended in a mixture of 2 N HCI (50 mL) and ethanol (10 mL) and refluxed for 10 h. After cooling the precipitated triphenylmethanol was filtered, and the filtrate was evaporated. The residue was suspended in 2 N NaOH (40 mL), and the aqueous phase was extracted with methylene chloride (3 x 50 mL). The combined methylene chloride extracts were washed with water (3 x 50 mL), dried (Na 2 SO 4 ), filtered, and evaporated to give 107 mg (18%) of the title compound as a hygroscopic solid: mp 63-67 °C; Η NMR (90 MHz CDCI 3 )d 1.50-2.00 (m, 6 H), 2.60 (m, 2 H), 3.45 (br m, 6 H), 4.63 (s, 2 H, ArCH 2 ), 5.95-7.50 (m, 9 H, ArH and NHC=SNH), 8.13 (d, J = 2.4 Hz, 1 H, pyridine H-6); 13 C NMR (90 MHz CDCI 3 )d 23.51 , 24.65, 28.88, 43.39, 44.37, 48.59, 50.87, 106.72, 107.37, 115.12, 126.23, 128.66, 130.56, 130.89, 132.62, 134.14, 138.20, 148.49, 156.29, 181.65. EXAMPLE 25 1 -(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) butyl)-3-(2-(1 H-imidazol- 4-yl)ethyl)thiourea A suspension of histamine (352 mg. 3.17 mmol) in THF (10 mL) was cooled to 0-5 °C and treated dropwise with 4-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)]aminobutyl isothiocyanate (1.41 g, 3.17 mmol) in THF (20 mL). After stirring overnight, the solvent was removed under reduced pressure to yield an oil which was purified by flash chromatography using a solvent system of EtOAc 85:CH 3 OH 15: concentrated NH 4 OH 1. Fractions homogeneous by TLC were combined and evaporated under reduced pressure to afford 1.59 g (90%) of the title compound as a white foam. 1 H NMR (90 MHz CDCI 3 )d 1.60 (m, 4 H), 2.80 (m, 2 H), 3.60 (m, 8 H), 4.63 (s, 2 H, ArCH 2 ), 6.37 (s, 1 H), 6.79-7.55 (m, 7 H, ArH and NHC=SNH), 8.16 (d, J = 2.2 Hz, 1 H); 13 C NMR (90 MHz CDCI 3 )d 24.65, 26.27, 26.65, 43.94, 44.21 , 48.49, 50.87, 106.72, 107.37, 115.34, 126.17, 128.61 , 130.56, 130.94, 132.62, 134.68, 139.82, 148.44, 156.29, 181.59. EXAMPLE 26 1-(5-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino) pentyl)-3-(3-(1H-imidazol- 4-yl)propyl)thiourea Following the general method as described for N-1-(5-bromopyrid-2-yl)ethane-1,2- diamine, 2,5-dibromopyridine (8.42 g, 35.5 mmol), pyridine (3.54 g, 44.8 mmol), and 1 ,5-diaminopentane (25.0 g, 244.7 mmol) gave an oil. Flash chromatography on silica gel using CH 2 CI 2 50: CH 3 OH 50:concentrated NH 4 OH 1 as the solvent afforded 5.50 g (60%) of N-1-(5-bromopyrid-2-yl)pentane-1 ,5-diamine as an oil. 1 μ NMR (90 MHz CDCI 3 )d 1.50 (m, 6 H), 1.85 (br s, 2 H, NH 2 ), 2.72 (m, 2 H), 3.25 (m, 2 H), 4.70 (br s, 1 H, NH), 6.30 (d, J = 9 Hz, 1 H, pyridine H-3), 7.47 (dd, 1 H, pyridine H-4), 8.09 (d, 1 H, pyridine H-6); 13 C NMR (90 MHz CDCI 3 )d 24.38, 29.40, 33.75, 41.88, 42.50, 106.88, 107.19, 140.00, 149.06, 157.50. In a similar manner as described for the synthesis of N-1-(5-bromopyrid-2-yl)-1-(3,4- dichlorobenzyl) ethane-1 ,2-diamine, a 60% mineral oil dispersion of sodium hydride (940 mg, 23.4 mmol), N-1-(5-bromopyrid-2-yl)pentane-1 ,5-diamine (5.50 g, 21.3 mmol), and 3,4-dichlorobenzyl chloride (4.60 g, 23.4 mmol) in DMSO (75 mL) afforded an oil. Purification by flash chromatography on silica gel using CH 2 CI 2 50: CH 3 OH 50: concentrated NH 4 OH 1 as the solvent gave 1.46 g (16%) of N-1 -(5- bromopyrid-2-yl)-1-(3,4-dichlorobenzyl)pentane-1 ,5-diamine as an oil. 1 H NMR (90 MHz CDCI 3 )d 1.35 (m, 6 H), 2.70 (m, 2 H), 3.40 (t, 2 H), 4.68 (s, 2 H, ArCH 2 ), 6.35 (d, J = 9 Hz, 1 H, pyridine H-3), 7.35 (m, 4 H, ArH), 8.15 (d, 1 H, pyridine H-6); 13 C NMR (90 MHz CDCI 3 )d 24.38, 27.19, 33.75, 42.20, 49.06, 50.63, 106.25, 107.50, 126.25, 127.81 , 130.94, 131.25, 131.90, 139.69, 140.00, 149.06, 156.56. Following the general method, DCC (722 mg, 3.50 mmol), carbon disulfide (2.84 g, 37.3 mmol), and N-1 -(5-bromopyrid-2-yl)-1-(3,4-dichlorobenzyl)pentane-1 ,5-diamine (1.46 g, 3.50 mmol) in THF (45 mL) gave an oil. Flash chromatography using hexane 80: EtOAc 20: Et 3 N 1 afforded 1.38 g (86%) of 5-[N-(5-bromopyrid-2-yl)-N-(3,4- dichlorobenzyl)]aminopentyl isothiocyanate as an oil. 1 H NMR (90 MHz CDCI 3 )d 1.60 (m, 6 H), 3.47 (m, 4 H), 4.69 (s, 2 H, ArCH 2 ), 6.35 (d, J = 9 Hz, 1 H, pyridine H-3), 7.33 (m, 4 H), 8.17 (d, 1 H, pyridine H-6); 13 C NMR (90 MHz CDCI 3 )d 23.99, 26.44, 29.63, 44.86, 48.65, 50.92, 106.72, 107.05, 126.23, 128.72, 130.51 , 132.62, 138.90, 139.66, 148.60, 156.24. A solution of 3-[1-(triphenylmethyl)imidazol-4-yl]propylamine (1.02 g, 2.77 mmol) was dissolved in THF (20 mL) and treated dropwise with a solution of 5-[N-(5-bromopyrid- 2-yl)-N-(3,4-dichloro benzyl)]aminopentyl isothiocyanate (1.27 g, 2.77 mmol) in THF (40 mL) at 0-5 °C under a nitrogen atmosphere. The reaction was allowed to warm to room temperature and was stirred overnight. The reaction mixture was treated with additional 3-[1-(triphenylmethyl)imidazol-4-yl]propylamine (0.182 g, 0.495 mmol) and was refluxed for 24 h. Removal of the solvent afforded an oil which was purified by flash chromatography on silica gel using a solvent system of EtOAc 92: CH 3 OH 4: Et 3 N 4. Fractions homogeneous by TLC were combined and evaporated to yield 2.20 g of a foam. The trityl-protected thiourea was refluxed in 1 N HCI (50 mL) for 1.5 h, and the precipitated triphenylmethanol was removed by filtration. The filtrate was extracted with diethyl ether (2 x 100 mL), washed with water (100 mL), adjusted to pH 14 with 1 N NaOH, and extracted with with ethyl acetate (3 x 100 mL). The combined ethyl acetate extracts were washed with water (2 x 50 mL), dried (Na 2 SO 4 ), filtered, and evaporated. The resulting residue was flash chromatographed on silica gel using EtOAc 85: CH 3 OH 15:concentrated NH 4 OH 1 as the eluent. Fractions homogeneous by TLC were combined and evaporated to yield 500 mg (31 %) of the title compound as a foam. 1 H NMR (90 MHz CDCI 3 )d 1.15-2.00 (m, 8H), 2.25 (m, 2 H), 3.45 (m, 6 H), 4.64 (s, 2 H, ArCH 2 ), 6.25-8.13 (m, 10 H, ArH and NHC=SNH); 13 C NMR (90 MHz CDCI 3 )d 23.86, 24.43, 26.98, 29.04, 43.61 , 44.64, 48.97, 50.98, 106.78, 107.48, 126.44, 128.88, 130.67, 134.35, 139.17, 139.93, 148.65, 156.51 , 181.70. Anal. Calcd. for C 24 H 29 BrCI 2 N 6 S: C, 49.32; H, 5.00; N, 14.38. Found: C, 49.12; H, 5.16; N, 14.15. EXAMPLE 27 N1-[3-(lmidazol-4(5)-yl)propyl]-N2-[3-[(4-bromobenzyl)-N-(pyridin-2-yl)-amino]propyl]- S-methylisothiourea hydroiodide dihydrochloride To a solution of N1-[3-(imidazol-4(5)-yl)propyl]-N2-[3-[N-(4-bromobenzyl)-N-(pyridin- 2-yl)-amino]propyl]-thiourea dihydrochloride (prepared as in example 1) (580 mg, 1.035 mmol) in absolute ethanol (50 ml) under an atmosphere of nitrogen was added iodomethane (0.10 ml, 1.279 mmol) and the reaction mixture was stirred for 60 h at room temperature. Iodomethane (0.025 ml, 0.32 mmol) was added and the reaction mixture stirred at room temperature for an additional 5 h. The volatiles were evapo¬ rated in vacuo affording 0.7 g (97%) of the title compound as an amorphous powder. TLC: Rf = 0.40 (Siθ2; Methanol/Triethylamine = 75:25). HPLC retention time = 12.58 minutes (5 μM C184 x 250 mm column, eluting with a gradient of 15% acetonitrile/0.1 N aqueous ammonium sulphate to 25% acetonitri¬ le/0.1 N aqueous ammonium sulphate, pH = 2.5, over 10 minutes at room temperatu- re) 1H NMR (200 MHz, D 3 COD) δμ 2.12 (m, 4H), 2.71 (s, 3H, SCH 3 ), 2.85 (t, 2H), 3.61 (m, 4H), 3.84 (m, 2H), 4.95 (s, 2H, CH r Ph), 7.02 (t, 1 H), 7.22 (d, 2H), 7.30 (d, 1H), 7.42 (bs, 1H), 7.52 (d, 2H), 7.98 (d, 1H), 8.05 (bs, 1H), 8.80 (d, 1H).

Claims: CLAIMS 1. A compound of general formula la or lb , B la or / R 2 B lb wherein 10 m is 2, 3, 4, 5 or 6, n is 1 , 2 or 3, p is 1 , 2, 3, 4, 5 or 6, R1 and R2 are independently hydrogen or Cι_β-alkyl optionally substituted with halogen, amino, hydroxy, alkoxy or aryl, 15 X is =S, =0, =NH, =NCOPh or =N(CN), A is aryl optionally substituted with halogen, amino, hydroxy, nitro, C-μβ-alkyl , Cι_β- alkoxy or aryl, B is aryl optionally substituted with halogen, amino, hydroxy, C<|_6-alkyl, C-ι_6-alkoxy or aryl, 20 D is aryl, amino, optionally substituted with halogen, amino, hydroxy, Cι_6-alkyl, C-|_ 6-alkoxy or aryl, or a pharmaceutically acceptable salt thereof. 2. A compound of general formula la ' 25 la wherein m is 2, 3, 4, 5 or 6, n is 1 , 2 or 3, p is 1, 2, 3, 4, 5 or 6, R1 and R2 are independently hydrogen or C-μβ-alkyl optionally substituted with halogen, amino, hydroxy, alkoxy or aryl, X is =S, =0, =NH, =NCOPh or =N(CN), A is aryl optionally substituted with halogen, amino, hydroxy, nitro, C-|_6-alkyl , C-j_6- alkoxy or aryl, B is aryl optionally substituted with halogen, amino, hydroxy, Cι_6-alkyl, C-|_6-alkoxy or aryl, D is aryl, amino, optionally substituted with halogen, amino, hydroxy, C<|_g-alkyl, C-j. 6-alkoxy or aryl, or a pharmaceutically acceptable salt thereof. 3. The compound according to claim 1 or 2, wherein X is =S, =NH, =NCOPh, or =N- CN, preferably =S, =NH or =NCOPh. 4. The compound according to any one of the preceding compound claims, wherein A is pyridinyl, quinolinyl, isoquinolinyl, pyrimidinyl, pyrazinyl, pyridazinyl or triazinyl optionally substituted with halogen, amino, hydroxy, nitro, C-j.g-alkyl , C<|_6-alkoxy or aryl. 5. The compound according to claim 4, wherein A is pyridine or quinoline optionally substituted with halogen, amino, hydroxy, nitro, C<ι_6-alkyl, C-μβ-alkoxy or aryl, pref¬ erably pyridine, pyridine substituted with bromo or nitro, or quinoline. 6. The compound according to any one of the preceding compound claims, wherein B is phenyl, naphthyl, quinolinyl, isoquinolinyl, indolyl, thienyl, furanyl or pyridinyl op¬ tionally substituted with halogen, amino, hydroxy, C^.g-alkyl, C-μβ-alkoxy or aryl. 7. The compound according to claim 6, wherein B is phenyl or naphthyl optionally substituted with halogen, amino, hydroxy, nitro, Cι_ρ-alkyl, C .g-alkoxy or aryl, pref¬ erably phenyl substituted with bromo or two chloro, or naphthyl. 8. The compound according to any one of the preceding compound claims, wherein D is amino, imidazolyl, pyridinyl, pyrimidinyl, piperidinyl, pyrrolidinyl, piperazinyl, pyridinylamino, pyrimidinylamino, piperidinylamino, pyrrolidinylamino, piperaziny- lamino, morpholinyl, triazolyl, tetrazolyl, thiadiazolyl, isoxazolyl or oxadiazolyl option¬ ally substituted with halogen, amino, hydroxy, C-|_6-alkyl, C-μe-alkoxy or aryl. 9. The compound according to claim 8, wherein D is imidazole, morpholinyl, pyr¬ rolidinyl, amino or pyridinylamino optionally substituted with halogen, amino, hydroxy, Cι_6-alkyl, C-|_6-alkoxy or aryl, preferably imidazole, morpholinyl, dimethylamino, pyrrolidinyl, pyridinylamino, amino or pyridinyl. 10. The compound according to any one of the preceeding compound claims, wherein R-| and R2 independently are hydrogen or C<ι_6-alkyl, preferably hydrogen or methyl. 11. The compound according to any one of the claims 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10 selected from the group consisting of N1-[3-(lmidazol-4(5)-yl)propyl]-N2-[3-[N-(4-bromobenzyl)-N-(pyridin-2-yl)- amino]propyl]-S-methylisothiourea, or the hydroiodide.dihydrochloride salt thereof; 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl) amino)propyl)-3-(3-(1 H- imidazol-4-yl)propyl)thiourea; 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(1H-imidazol-4- yl)propyl)thiourea, or the dihydrochloride salt thereof; 1-(4-AminobutyI)-3-(3-(N-(5-bromopyridin-2-yl)-N-(3,4- dichlorobenzyl)amino)propyl)thiourea; 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl) amino)propyl)-3-(3-(N-(pyridin-2- yl)amino)propyl)thiourea; 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-N,N- dimethylaminopropyl)thiourea; 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(morpholin-4- yl)propyl)thiourea; 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(imidazol-1- yl)propyl)thiourea, or the dihydrobromide salt thereof; 1-(4-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)butyl)-3-(3-(imidazol-1- yl)propyl)thiourea; 1-(4-(N-(3,4-Dichlorobenzyl)-N-(pyridin-2-yl)amino)butyl)-3-(3-(imidazol-1- yl)propyl)thiourea; 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)propyl)-3-(3-(imidazol-1- yl)propyl)thiourea; 1 -(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)butyl)-3-(3-(imidazol-1 - yl)propyl)thiourea; 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(4-(N-(pyridin-2- yl)amino)propyl)thiourea; 1-(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)butyl)-3-(3-(1H-imidazol- 4-yl)propyl)thiourea; 1-(5-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)pentyl)-3-(3-(1H-imidazol- 4-yl)propyl)thiourea; 1-(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)butyl)-3-(2-(1 H-imidazol- 4-yl)ethyl)thiourea; 1 -(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(2-(1 H-imidazol- 4-yl)ethyl)thiourea; 1-(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(3-(1H-imidazol- 4-yl)propyl)thiourea; 1-(3-(N-(5-Bromopyridin-2-yl)-N-((naphth-1-yl)methyl) amino)propyl)-3-(3-(1H- imidazol-4-yl)propyl)thiourea; 1-(4-Aminobutyl)-3-(3-(N-(5-bromopyridin-2-yl)-N-((naphth-1- yl)methyl)amino)propyl)thiourea; 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)propyl)-3-(2-(pyrid-2- yl)ethyl)thiourea; 1 -(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)propyl)-3-(3-(pyrrolidin-1 - yl)propyl)thiourea; 1-(4-Aminobutyl)-3-[3-[N-(5-bromopyrid-2-yl)]-[N-(3,4- dichlorobenzyl)]aminopropyl]thiourea; 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)propyl)-3-(4-(N-(pyridin-2- yl)amino)propyl)thiourea; 1-(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(3- dimethylaminopropyl)thiourea; 1-(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(3-(pyrrolidin-1- yl)propyl)thiourea; 1-(2-(N-(5-Nitropyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(3-(1H-imidazol-4- yl)propyl)thiourea; 1-[3-[((4-Bromobenzyl)pyridin-2-yl)amino]propyl]-3-[2-(1H-imidazol-4- yl)propyl]guanidine; 1-[3-[((4-Bromobenzyl)pyridin-2-yl)amino]propyl]-3-[2-(1 H-imidazol-4- yl)ethyl]guanidine; 1-[3-[((4-Bromobenzyl)pyridazin-2-yl)amino]propyl]-3-[3-(1H-imidazol-4- yl)propyl]guanidine; 1-[3-[((4-Bromobenzyl)pyridin-3-yl)amino]propyl]-3-[3-(1H-imidazol-4- yl)ethyl]guanidine; 1-[3-[N-(4-Bromobenzyl)-N-(pyrimidin-2-yl)amino]propyl]- 3-[3-(1 H-imidazol-4- yl)propyl]guanidine; 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[3-(imidazol-1- yl)propyl]guanidine; 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[3-[N-(pyridin-2- yl)amino]propyl]guanidine; 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[2-(pyridin-2- yl)ethyl]guanidine; 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[3-(morpholin-4- yl)propyl]guanidine; 1-Methyl-1-[3-(N,N-dimethylamino)propyl]-3-[3-[N-(4-bromobenzyl)-N-(pyridin-2- yl)amino]propyl]guanidine; 1-BenzoyI-2-[3-[((4-bromobenzyl)quinol-2-yl)amino]-propyI]-3-[3-(1H-imidazol-4- yl)propyl]guanidine; 1-[3-[N-(4-Bromo-benzyl)-N-(quinolin-2-yl)amino]-propyl]- 3-[3-(1/-/-imidazol-4- yl)propyl]guanidine, or the trihydrochloride salt thereof; or 1 -[3-[N-(4-bromobenzyl)-N-(quinolin-2-yl)amino]propyl]- 2-Benzoyl-3-[3-(1 H-imidazol- 4-yl)propyl]guanidine. 12. A pharmaceutical composition comprising, as an active ingredient, a compound of the general formula I according to any one of the preceeding compound claims, or a pharmaceutically acceptable salt thereof together with a pharmaceutically acceptable carrier or diluent. 13. The composition according to claim 12 in unit dosage form, comprising from about 10 to about 200 mg of the compound of the general formula I or a pharmaceu¬ tically acceptable salt thereof. 14. A pharmaceutical composition for mediating the biological effect of somatostatin agonists or antagonists, the composition comprising, as an active ingredient, a com¬ pound of the general formula I according to any one of the preceeding compound claims, or a pharmaceutically acceptable salt thereof together with a pharmaceutically acceptable carrier or diluent. 15. A pharmaceutical composition according to any one of the claims 12-14 for oral, nasal, transdermal, pulmonal or parenteral administration. 16. A method of mediating the biological effect of somatostatin agonists or antago¬ nists, the method comprising administering to a subject in need thereof an effective amount of a compound according to any one of the preceeding compound claims, or a pharmaceutically acceptable salt thereof, or of a composition according to any one of the preceeding composition claims. 17. A method according to claim 16, wherein the effective amount of the compound according to any one of the preceeding compound claims or pharmaceutically ac¬ ceptable salt or ester thereof is in the range of from about 0.0001 to about 100 mg/kg body weight per day, preferably from about 0.001 to about 50 mg/kg body weight per day. 18. Use of a compound according to any one of the preceeding compound claims or a pharmaceutically acceptable salt thereof for the preparation of a medicament. 19. Use of a compound according to any one of the preceeding compound claims or a pharmaceutically acceptable salt thereof for the preparation of a medicament for mediating the biological effect of somatostatin agonists or antagonists. 20. Use of a compound according to any one of the preceeding compound claims for the development of pharmaceutical, therapeutic, and diagnostic techniques. 21. A method for producing a prophylactic or therapeutic respons in a mammal by administstering to the mammal a pharmaceutically effective amount of one or more compounds according to any one of the preceeding compound claims. 22. Use of a compound selected from the group consisting of 1-(3-(1H-lmidazol-4-yl)propyl)-3-(2-(N-benzyl-N-(3,5-dimethylpyridin-2- yl)ethyl)guanidine; 1-(3-(1H-lmidazol-4-yl)propyl)-3-(5-(N-(4-bromobenzyl)-N-(ρyridin-2- yl)amino)pentyl)guanidine; or 1-(3-(1H-lmidazol-4-yl)propyl)-3-(4-(N-(3,4-dichlorobenzyl)-N-(pyridin-2- yl)amino)butyl)guanidine, or the pharmaceutically acceptable salts thereof, for the preparation of a medicament for mediating the biological effect of somatostatin agonists or antagonists. 23. A somatostatin receptor ligand of nonpeptide origin which has selective affinity to one or two of the somatostatin receptor proteins selected from SST1 , SST2, SST3, SST4 and SST5. 24. A compound according to claim 1 , 2 or 23 having affinity to SST1. 25. A compound according to claim 1 , 2 or 23 having affinity to SST2. 26. A compound according to claim 1 , 2 or 23 having affinity to SST3. 27. A compound according to claim 1 , 2 or 23 having affinity to SST4. 28. A compound according to claim 1 , 2 or 23 having affinity to SST5. 29. A pharmaceutical composition for mediating the biological effect of somatostatin agonists or antagonists, the composition comprising, as an active ingredient, a com- pound according to any one of the claims 23-28, or a pharmaceutically acceptable salt thereof together with a pharmaceutically acceptable carrier or diluent. 30. Use of a compound according to any one of the claims 23-28, or a pharmaceuti¬ cally acceptable salt thereof for the preparation of a medicament for mediating the biological effect of somatostatin agonists or antagonists. AMENDED CLAIMS [received by the International Bureau on 13 October 1997 (13.10.97); original claim 3 amended; remaining claims unchanged (8 pages)] 1. A compound of general formula la or lb B la or / R 2 - B lb wherein m is 2, 3, 4, 5 or 6, n is 1 , 2 or 3, p is 1 , 2, 3, 4, 5 or 6, R1 and R 2 - are independently hydrogen or C-|_ρ-alkyl optionally substituted with halogen, amino, hydroxy, alkoxy or aryl, X is =S, =0, =NH, =NCOPh or =N(CN). A is aryl optionally substituted with halogen, amino, hydroxy, nitro, C-|_g-alkyl , C-μg- alkoxy or aryl, B is aryl optionally substituted with halogen, amino, hydroxy, C-μg-alkyl, C-μg-alkoxy or aryl, D is aryl, amino, optionally substituted with halogen, amino, hydroxy, C-μg-alkyl, C-^. g-alkoxy or aryl, or a pharmaceutically acceptable salt thereof. 2. A compound of general formula la la wherein m is 2, 3, 4, 5 or 6, n is 1 , 2 or 3, p is 1, 2, 3, 4, 5 or 6, R1 and R2 are independently hydrogen or C-|_g-alkyl optionally substituted with halogen, amino, hydroxy, alkoxy or aryl, X is =S, =0, =NH, =NCOPh or =N(CN), A is aryl optionally substituted with halogen, amino, hydroxy, nitro, C-μg-alkyl , C<|_g- alkoxy or aryl, B is aryl optionally substituted with halogen, amino, hydroxy, C-μg-alkyl, C-i.g-alkoxy or aryl, D is aryl, amino, optionally substituted with halogen, amino, hydroxy, Cι_g-alkyl, C-μ g-alkoxy or aryl, or a pharmaceutically acceptable salt thereof. 3. The compound according to claim 1 or 2, wherein X is =S. 4. The compound according to any one of the preceding compound claims, wherein A is pyridinyl, quinolinyl, isoquinolinyl, pyrimidinyl, pyrazinyl, pyridazinyl or triazinyl optionally substituted with halogen, amino, hydroxy, nitro, C^.g-alkyl , C-j. g-alkoxy or aryl. 5. The compound according to claim 4, wherein A is pyridine or quinoline optionally substituted with halogen, amino, hydroxy, nitro, C-μg-alkyl, C-μg-alkoxy or aryl, pref- erably pyridine, pyridine substituted with bromo or nitro, or quinoline. 6. The compound according to any one of the preceding compound claims, wherein B is phenyl, naphthyl, quinolinyl, isoquinolinyl, indolyl, thienyl, furanyl or pyridinyl op¬ tionally substituted with halogen, amino, hydroxy, C-μg-alkyl, C-μg-alkoxy or aryl. 7. The compound according to claim 6, wherein B is phenyl or naphthyl optionally substituted with halogen, amino, hydroxy, nitro, C-j.g-alkyl, C^ .g-alkoxy or aryl, pref¬ erably phenyl substituted with bromo or two chloro, or naphthyl. 8. The compound according to any one of the preceding compound claims, wherein D is amino, imidazolyl, pyridinyl, pyrimidinyl, piperidinyl, pyrrolidinyl, piperazinyl, pyridinylamino, pyrimidinylamino, piperidinylamino, pyrrolidinylamino, piperaziny- lamino, morpholinyl, triazolyl, tetrazolyl, thiadiazolyl, isoxazolyl or oxadiazolyl option¬ ally substituted with halogen, amino, hydroxy, C-|.g-alkyl, C-μg-alkoxy or aryl. 9. The compound according to claim 8, wherein D is imidazole, morpholinyl, pyr¬ rolidinyl, amino or pyridinylamino optionally substituted with halogen, amino, hydroxy, C-|.g-alkyl, Cι_g-alkoxy or aryl, preferably imidazole, morpholinyl, dimethylamino, pyrrolidinyl, pyridinylamino, amino or pyridinyl. 10. The compound according to any one of the preceeding compound claims, wherein R-| and R2 independently are hydrogen or Cι_g-alkyl, preferably hydrogen or methyl. 11. The compound according to any one of the claims 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10 selected from the group consisting of N1-[3-(lmidazol-4(5)-yl)propyl]-N2-[3-[N-(4-bromobenzyl)-N-(pyridin-2-yl)- amino]propyl]-S-methylisothiourea, or the hydroiodide.dihydrochloride salt thereof; 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl) amino)propyl)-3-(3-(1H- imidazol-4-yl)propyl)thiourea; 1 -(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(1 H-imidazol-4- yl)propyl)thiourea, or the dihydrochloride salt thereof; 1-(4-Aminobutyl)-3-(3-(N-(5-bromopyridin-2-yl)-N-(3,4- dichlorobenzyl)amino)propyl)thiourea; 1 -(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl) amino)propyl)-3-(3-(N-(pyridin-2- yl)amino)propyl)thiourea; 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-N,N- dimethylaminopropyl)thiourea; 1-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(morpholin-4- yl)propyl)thiourea; 1 -(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(3-(imidazol-1 - yl)propyl)thiourea, or the dihydrobromide salt thereof; 1-(4-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)butyl)-3-(3-(imidazol-1- yl)propyl)thiourea; 1-(4-(N-(3,4-Dichlorobenzyl)-N-(pyridin-2-yl)amino)butyl)-3-(3-(imidazol-1- yl)propyl)thiourea; 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)propyl)-3-(3-(imidazol-1- yl)propyl)thiourea; 1-(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)butyl)-3-(3-(imidazol-1- yl)propyl)thiourea; 1 -(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-3-(4-(N-(pyridin-2- yl)amino)propyl)thiourea; 1-(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)butyl)-3-(3-(1H-imidazol- 4-yl)propyl)thiourea; 1-(5-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)pentyl)-3-(3-(1H-imidazol- 4-yl)propyl)thiourea; 1-(4-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)butyl)-3-(2-(1H-imidazol- 4-yl)ethyl)thiourea; 1-(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(2-(1H-imidazol- 4-yl)ethyl)thiourea; 1 -(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(3-(1 H-imidazol- 4-yl)propyl)thiourea; 1-(3-(N-(5-Bromopyridin-2-yl)-N-((naphth-1-yl)methyl) amino)propyl)-3-(3-(1 H- imidazol-4-yl)propyl)thiourea; 1 -(4-Aminobutyl)-3-(3-(N-(5-bromoρyridin-2-yl)-N-((naphth-1 - yl)methyl)amino)propyl)thiourea; 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)propyl)-3-(2-(pyrid-2- yl)ethyl)thiourea; 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)propyl)-3-(3-(pyrrolidin-1- yl)propyl)thiourea; 1 -(4-Aminobutyl)-3-[3-[N-(5-bromopyrid-2-yl)]-[N-(3,4- dichlorobenzyl)]aminopropyl]thiourea; 1-(3-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)propyl)-3-(4-(N-(pyridin-2- yl)amino)propyl)thiourea; 1-(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(3- dimethylaminopropyl)thiourea; 1-(2-(N-(5-Bromopyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(3-(pyrrolidin-1- yl)propyl)thiourea; 1-(2-(N-(5-Nitroρyridin-2-yl)-N-(3,4-dichlorobenzyl)amino)ethyl)-3-(3-(1H-imidazol-4- yl)propyl)thiourea; 1-[3-[((4-Bromobenzyl)pyridin-2-yl)amino]propyl]-3-[2-(1 H-imidazol-4- yl)propyl]guanidine; 1-[3-[((4-Bromobenzyl)pyridin-2-yl)amino]propyl]-3-[2-(1H-imidazol-4- yl)ethyl]guanidine; 1-[3-[((4-Bromobenzyl)pyridazin-2-yl)amino]propyl]-3-[3-(1H-imidazol-4- yl)propyl]guanidine; 1-[3-[((4-Bromobenzyl)pyridin-3-yl)amino]propyl]-3-[3-(1H-imidazol-4- yl)ethyl]guanidine; 1 -[3-[N-(4-Bromobenzyl)-N-(pyrimidin-2-yl)amino]propyl]- 3-[3-( 1 H-imidazol-4- yl)propyl]guanidine; 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[3-(imidazol-1- yl)propyl]guanidine; 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[3-[N-(pyridin-2- yl)aminoJpropyl]guanidine; 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[2-(pyridin-2- yl)ethyl]guanidine; 1-[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propyl]-3-[3-(morpholin-4- yl)propyl]guanidine; 1-Methyl-1-[3-(N,N-dimethylamino)propyl]-3-[3-[N-(4-bromobenzyl)-N-(pyridin-2- yl)amino]propyl]guanidine; 1-Benzoyl-2-[3-[((4-bromobenzyl)quinol-2-yl)amino]-propyl]-3-[3-(1H-imidazol-4- yl)propyl]guanidine; 1 -[3-[N-(4-Bromo-benzyl)-N-(quinolin-2-yl)amino]-propyl]- 3-[3-(1 /-/-imidazol-4- yl)propyl]guanidine, or the trihydrochloride salt thereof; or 1 -[3-[N-(4-bromobenzyl)-N-(quinolin-2-yl)amino]propyl]- 2-Benzoyl-3-[3-(1 H-imidazol- 4-yl)propyl]guanidine. 12. A pharmaceutical composition comprising, as an active ingredient, a compound of the general formula I according to any one of the preceeding compound claims, or a pharmaceutically acceptable salt thereof together with a pharmaceutically acceptable carrier or diluent. 13. The composition according to claim 12 in unit dosage form, comprising from about 10 to about 200 mg of the compound of the general formula I or a pharmaceu¬ tically acceptable salt thereof. 14. A pharmaceutical composition for mediating the biological effect of somatostatin agonists or antagonists, the composition comprising, as an active ingredient, a com¬ pound of the general formula I according to any one of the preceeding compound claims, or a pharmaceutically acceptable salt thereof together with a pharmaceutically acceptable carrier or diluent. 15. A pharmaceutical composition according to any one of the claims 12-14 for oral, nasal, transdermal, pulmonal or parenteral administration. 16. A method of mediating the biological effect of somatostatin agonists or antago- nists, the method comprising administering to a subject in need thereof an effective amount of a compound according to any one of the preceeding compound claims, or a pharmaceutically acceptable salt thereof, or of a composition according to any one of the preceeding composition claims. 17. A method according to claim 16, wherein the effective amount of the compound according to any one of the preceeding compound claims or pharmaceutically ac¬ ceptable salt or ester thereof is in the range of from about 0.0001 to about 100 mg/kg body weight per day, preferably from about 0.001 to about 50 mg/kg body weight per day. 18. Use of a compound according to any one of the preceeding compound claims or a pharmaceutically acceptable salt thereof for the preparation of a medicament. 19. Use of a compound according to any one of the preceeding compound claims or a pharmaceutically acceptable salt thereof for the preparation of a medicament for mediating the biological effect of somatostatin agonists or antagonists. 20. Use of a compound according to any one of the preceeding compound claims for the development of pharmaceutical, therapeutic, and diagnostic techniques. 21. A method for producing a prophylactic or therapeutic respons in a mammal by administstering to the mammal a pharmaceutically effective amount of one or more compounds according to any one of the preceeding compound claims. 22. Use of a compound selected from the group consisting of 1-(3-(1H-lmidazol-4-yl)propyl)-3-(2-(N-benzyl-N-(3,5-dimethylpyridin-2- yl)ethyl)guanidine; 1-(3-(1H-lmidazol-4-yl)propyl)-3-(5-(N-(4-bromobenzyl)-N-(pyridin-2- yl)amino)pentyl)guanidine; or 1-(3-(1H-lmidazol-4-yl)propyl)-3-(4-(N-(3,4-dichlorobenzyl)-N-(pyridin-2- yl)amino)butyl)guanidine, or the pharmaceutically acceptable salts thereof, for the preparation of a medicament for mediating the biological effect of somatostatin agonists or antagonists. 23. A somatostatin receptor ligand of nonpeptide origin which has selective affinity to one or two of the somatostatin receptor proteins selected from SST1 , SST2, SST3, SST4 and SST5. 24. A compound according to claim 1 , 2 or 23 having affinity to SST1. 25. A compound according to claim 1 , 2 or 23 having affinity to SST2. 26. A compound according to claim 1 , 2 or 23 having affinity to SST3. 27. A compound according to claim 1 , 2 or 23 having affinity to SST4. 28. A compound according to claim 1 , 2 or 23 having affinity to SST5. 29. A pharmaceutical composition for mediating the biological effect of somatostatin agonists or antagonists, the composition comprising, as an active ingredient, a com¬ pound according to any one of the claims 23-28, or a pharmaceutically acceptable salt thereof together with a pharmaceutically acceptable carrier or diluent. 30. Use of a compound according to any one of the claims 23-28, or a pharmaceuti¬ cally acceptable salt thereof for the preparation of a medicament for mediating the biological effect of somatostatin agonists or antagonists. STATEMENT UNDER ARTICLE 19 Enclosed please find a new set of claims (pages 81 through 88) to replace the claims originally filed with the above-referenced international applica¬ tion (pages 81 through 88). An amendment has been made in claim 3, in which X is now defined as S only. The amendment does not have any impact on the description and does not go beyond the disclosure in the international application as filed.

Inventors: ANDERSEN HENRIK SUNE, ANKERSEN MICHAEL, STIDSEN CARSTEN ENGGAARD, ANDERSEN, HENRIK, SUNE, ANKERSEN, MICHAEL, STIDSEN, CARSTEN, ENGGAARD
Applicants: ANDERSEN HENRIK SUNE, ANKERSEN MICHAEL, NOVONORDISK AS, STIDSEN CARSTEN ENGGAARD, ANDERSEN, HENRIK, SUNE, ANKERSEN, MICHAEL, NOVO NORDISK A/S, STIDSEN, CARSTEN, ENGGAARD
Application year: 1997
Main classification: C07D401
IPC codes: A61K31, A61P1, A61P5, A61P9, A61P35, A61P43, C07D213, C07D215, C07D401