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Abstract

A process for the preparation of imidazo[1,2-a]pyridine derivatives of the formula I: wherein R is hydrogen, halogen or a C.sub.1-C.sub.4 alkyl group; R.sup.1 and R.sup.2 are independently hydrogen, a straight or branched C.sub.1-C.sub.6 alkyl group which is unsubstituted or substituted by one or more halogen atoms, hydroxyl, N(C.sub.1-C.sub.4 alkyl).sub.2, carbamoyl or C.sub.1-C.sub.4 alkoxy radicals, a C.sub.1-C.sub.6 alkyl hydroxy group, a C.sub.3-C.sub.6 cycloalkyl radical, a benzyl radical, a phenyl radical or R.sup.1 and R.sup.2 together with the nitrogen atom to which they are bonded are joined together to form a substituted or unsubstituted heterocyclic group optionally containing one or more additional heterocyclic atoms; and R.sup.3 and R.sup.4 are independently hydrogen, halogen or a C.sub.1-C.sub.4 alkyl group, or a pharmaceutically acceptable salt thereof, the process comprising (a) reacting an imidazo[1,2-a]pyridine carboxylic acid of the formula II wherein R, R.sup.3 and R.sup.4 have the aforestated meanings with a halogenating agent in the absence of a solvent to form an acid halide intermediate and (b) reacting the acid halide intermediate with an amine of the formula HNR.sup.1R.sup.2 wherein R.sup.1 and R.sup.2 have the aforestated meanings to form the compound of formula I.

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