2-ALKYL-3-ACYLPYRAZOLO(1,5-A)PYRIDINES

1378375 2-Alkyl-3-alkanoyl-pyrazolo-[1,5-a]- pyridines KYORIN SEIYAKU KK 29 March 1973 [30 March 1972] 15037/73 Heading C2C [Also in Division A5] Novel 2-alkyl-3-alkanoyl-pyrazolo-[1,5-α]pyridines of the general formula wherein R1 is a straight- or branched-chain C 1-5 alkyl group, R2 is a hydrogen atom or methyl group and R3 is a hydrogen or halogen atom or a methyl, methoxy, acetoxy or hydroxy group, R2 and R3 being at any position on the pyridine ring, provided that (i) R1 is not a methyl group when each of R2 and R3 is a hydrogen atom and (ii) R1 is not a methyl group when R2 is a hydrogen atom and R3 is a methyl group at the 7-position, are prepared (a) by reacting a 1- amino-2-methyl-pyridinium salt of the general formula wherein X(-) is an anion, with an alkanoic acid of the general formula R1COOH or a functional derivative thereof in the presence of a base (a hydroxy group R3 may be converted to an acetoxy group in the course of the reaction); and (b) when R3 is a hydroxy group, by hydrolysis of the corresponding compound in which R3 is an acetoxy group. Pharmaceutical compositions having coronary, cerebral, femoral and tracheal dilating, respiratory stimulating and hypotensive activity comprise, as active ingredient, at least one 2- alkyl-3-alkanoylpyrazolo-[1,5-a)pyridine of the first general formula above, in association with a suitable pharmaceutical vehicle.