Patent GB-1425505-A (GB)
Title: 5-substituted 2-amino-4-arylthiazoles and their preparation
IPC: C07D277/20
Filed: 1973-02-26
Abstract: 1425505 5-Substituted-2-amino-4-arylthiazoles ISTITUTO LUSO FARMACO D'ITALIA SRL 26 Feb 1973 [25 Feb 1972 9 Feb 1973] 9382/73 Heading C2C Novel compounds of Formula I in which X represents hydrogen, halogen, hydroxy, lower alkoxy, lower alkyl, or halogensubstituted lower alkyl; R and R<SP>1</SP>, which are the same or different, represent hydrogen, lower alkyl, cycloalkyl, aryl (unsubstituted or substituted by halogen, hydroxy, lower alkoxy or lower alkyl) or aralkyl, or R and R<SP>1</SP>, together with the adjacent nitrogen atom, form a saturated heterocyclic ring, optionally containing other heteroatoms, and, when R represents hydrogen, R<SP>1</SP> may also represent -CO-R<SP>111</SP>, where R<SP>111</SP> is hydrogen, alkyl, aryl, amino or arylamino; R<SP>11</SP> represents hydroxy, or OR<SP>IV</SP>, where R<SP>IV</SP> is straight or branched alkyl, hydroxyalkyl, or aralkyl, aminoalkyl or aminoalkoxyalkyl, in which the amino group is primary or mono- or di-substituted by lower alkyl or is included in a heterocyclic ring, or R<SP>11</SP> represents VIII: in which R<SP>V</SP> and R<SP>VI</SP>, which may be the same or different, represent hydrogen, straight, branched, or cyclic lower alkyl, hydroxyalkyl or aralkyl, aminoalkyl in which the amino group is primary or, mono- or di-substituted by alkyl or is included in a heterocyclic ring, hydroxy, acyloxy or aryl either unsubstituted or substituted by alkyl or halogen; or the group of Formula VIII above represents pyrrolidino piperidino, morpholino, piperazino, or N<SP>1</SP>-substituted piperazino, and n represents the figures 1, 2 or 3, provided that when R and R<SP>1</SP> represent hydrogen and X represents hydrogen or 4-Cl or 4-OCH 3  and n= 1 or 2, R<SP>11</SP> is not OH or ethoxy, and its pharmaceutically acceptable salts, are prepared by one of the following methods: (a) reaction of a compound of Formula II: wherein Y is OH, alkylsulphonyloxy, arylsulphonyloxy or halogen and Z is CN, COOH or an ester thereof, with a compound of Formula III: and optionally further converting Z where required into COR<SP>11</SP>; (b) a compound of Formula V: is reacted with an amine RNHR<SP>1</SP> and Z is converted where required into COR<SP>11</SP>; (c) a compound of Formula VII: wherein Hal is Cl or Br is reacted with an amine RHNR<SP>1</SP> and COO-alkyl is optionally further converted where required into COR<SP>11</SP>; or (d) compounds of Formula I above in which R is H and R<SP>1</SP> is COR<SP>111</SP> are prepared by reacting a compound R = R<SP>1</SP> = H with an acid of formula R<SP>111</SP>-COOH or a reactive derivative thereof or with phosgene followed by ammonia or an amine. (2 - Amino - 4 - phenyl - thiazol - 5 - yl) - acetic acid, (2 - amino - 4 - p - chlorophenyl - thiazol - 5- yl)-acetic acid, (2-amino-4-anisyl-thiazol-5-yl)- acetic acid and their ethyl esters are similarly prepared. Pharmaceutical compositions in conventional forms for oral, parenteral or topicaladministration and having anti-inflammatory, antipyretic, analgesic, antibacterial, C.N.S. depressant, antiulcer and anti-cough activities comprise an above novel compound and a carrier therefor. The composition may be in the form of ointments, tablets, capsules or phials. The said forms may also comprise therapeutic compositions containing the specific compounds referred to immediately above. Ethyl (2 - hydroxy - 4p - chlorophenyl - thiazol- 5-yl)-acetate is prepared by reacting ethyl #- bromo-#-p-chlorobenzoylpropionate with ethyl thiocarbamate.