CARBOXAMIDO DERIVATIVES OF 5H-1,3,4-THIADIAZOLO 3,2-ALPHA PYRIMIDINES AND PROCESSES FOR THEIR PREPARATION

摘要

The present invention relates to new carboxamido-derivatives of 5H-1,3,4-thiadiazolo[3,2-a]pyrimidines, to a process for their preparation and to pharmaceutical (i.e. anti-inflammatory and analgesic) compositions containing them. The invention provides compounds having the following general formula (I) IMAGE (1) wherein R1 represents: (a) a hydrogen or halogen atom or a C1-C6 alkyl group unsubstituted or substituted by C1-C6 alkoxy; (b) a IMAGE group, wherein n is zero, 1, 2 or 3 and each of R4 and R5 is, independently, hydrogen or C1-C6 alkyl, or R4 and R5, taken together with the nitrogen atom to which they are linked, form an unsubstituted N-pyrrolidinyl ring or a piperidino, morpholino, N-piperazinyl or IMAGE ring, wherein m is zero, 1 or 2, the piperidino and morpholino rings are unsubstituted or substituted by one or two C1-C6 alkyl groups and the N-piperazinyl ring is unsubstituted or substituted by a substituent chosen from C1-C6 alkyl, phenyl and pyridyl; (c) trihalomethyl or a R6-S(O)p- group, wherein p is zero, 1 or 2 and R6 is C1-C6 alkyl or benzyl, wherein the phenyl ring is unsubstituted or substituted by a substituent chosen from halogen, C1-C6 alkyl and C1-C6 alkoxy; or (d) an unsubstituted pyridyl, pyridyl-N-oxide or thienyl ring or a phenyl ring unsubstituted or substituted by one, two or three substituents independently chosen from halogen, C1-C6 alkyl, C1-C6 alkoxy, hydroxy, formyloxy, C2-C8 alkanoyloxy, nitro, amino, formylamino, C2-C8 alkanoylamino and di-(C1-C6) alkyl-amino; R2 represents a hydrogen atom or a C1-C6 alkyl group; R3 represents: (a') a phenyl ring, unsubstituted or substituted by one or two substituents independently chosen from C1-C6 alkyl, C1-C6 alkoxy and halogen; (b') an unsaturated heteromonocyclic or heterobicyclic ring, containing one or more heteroatoms chosen from nitrogen and sulphur, unsubstituted or substituted by one or two substituents independently chosen from halogen, C1-C6 alkyl and C1-C6 alkoxy; and the pharmaceutically acceptable salts thereof.