Compounds of general formula (I) ##STR1## wherein R.sub.1 is a 2-pyridyl, 3-pyridyl or 4-pyridyl group; (b) a phenyl ring, unsubstituted or substituted by one or two groups chosen from halogen, trihalo-C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.6 alkyl, nitro, amino and C.sub.2 -C.sub.6 alkanoylamino; (c) benzyl; or (d) C.sub.1 -C.sub.6 alkyl;each of R.sub.2 and R.sub.3 independently is a hydrogen or a halogen atom or C.sub.1 -C.sub.6 alkyl;R.sub.4 is hydrogen, C.sub.1 -C.sub.6 alkyl or phenyl;R.sub.5 is (a') ##STR2## wherein each of R.sub.6 and R.sub.7 independently is hydrogen or C.sub.1 -C.sub.6 alkyl, or R.sub.6 and R.sub.7, taken together with the nitrogen atom to which they are linked, form a morpholino, piperidino, N-pyrrolidinyl or N-piperazinyl ring, wherein the N-piperazinyl ring is unsubstituted or substituted by C.sub.1 -C.sub.6 alkyl;(b') a ##STR3## wherein R.sub.8 is hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or halogen;(c') --NHR.sub.9, wherein R.sub.9 is a 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrimidinyl, 2-pyrazinyl, 3-pyrazolyl, 2-thiazolyl or 2-benzothiazolyl group, each of these groups being unsubstituted or substituted by one or two groups chosen from halogen, C.sub.1 -C.sub.6 alkyl, phenyl, hydroxy and C.sub.1 -C.sub.6 alkoxy;(d') ##STR4## wherein m is 1, 2 or 3 and R.sub.6 and R.sub.7 are as defined above; or the pharmaceutically acceptable salts thereof; are disclosed as anti-inflammatory agents.