Abstract: Compounds which are imidazo[1,2-a]pyridine derivatives of general formula (I) ##STR1## in which each of X.sub.1, X.sub.2, X.sub.3, independently of each other, is hydrogen, halogen, C.sub.1 -C.sub.4 alkyl, methoxy, methylthio, ethylthio, methylsulphonyl, nitro, amino, methylamino, dimethylamino, acetylamino or diacethylamino, Y is hydrogen, chlorine or methyl, R.sub.1 is hydrogen, C.sub.1 -C.sub.4 alkyl or benzyl, R.sub.2 is C.sub.1 -C.sub.6 alkyl, cyclohexyl, trichloromethyl, 1-propenyl, allyl, phenyl, 4-chlorophenyl or benzyl, or R.sub.1 and R.sub.2 together represent a divalent C.sub.3 -C.sub.5 alipathic group and their pharmaceutically acceptable acid salts have anxiolytic, sleep-inducing, hypnotic, anticonvulsant, analgesic and anti-ulcer properties.