| abstract |
A process for the preparation of imidazo[1,2-a]pyridine derivatives of the formula I: n n nwherein R is hydrogen, halogen or a C 1 -C 4 alkyl group; R 1 and R 2 are independently hydrogen, a straight or branched C 1 -C 6 alkyl group which is unsubstituted or substituted by one or more halogen atoms, hydroxyl, N(C 1 -C 4 alkyl) 2 , carbamoyl or C 1 -C 4 alkoxy radicals, a C 1 -C 6 alkyl hydroxy group, a C 3 -C 6 cycloalkyl radical, a benzyl radical, a phenyl radical or R 1 and R 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 3 and R 4 are independently hydrogen, halogen or a C 1 -C 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 n n nwherein R, R 3 and R 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 1 R 2 wherein R 1 and R 2 have the aforestated meanings to form the compound of formula I. |