Antitussive compounds of the formula I ##STR1## or physiologically acceptable acid addition salts thereof are disclosed, where A stands for straight or branched chain C.sub.1-5 alkylene or ##STR2## R.sub.1 stands for straight or branched chain C.sub.1-10 alkyl, halogenoalkyl, hydroxyalkyl, C.sub.5-6 cycloalkyl, vinyl, 2-ethoxyethyl, carbonylalkyl or aminoalkyl of the formula ##STR3## wherein R stands for hydrogen or methyl, n is 0 to 3,R.sub.2 stands for hydrogen or straight or branched chain alkyl,R.sub.3 stands for hydrogen or straight or branched chain alkyl or,R.sub.2 and R.sub.3 together with the nitrogen atom may form a 5-6 membered ring, which ring can optionally contain an oxygen or a second nitrogen atom, the latter, optionally substituted by methyl or,R.sub.1 can stand for a phenyl group of the formulaR.sub.4 R.sub.5 C.sub.6 H.sub.3 whereinR.sub.4 and R.sub.5 represent independently hydrogen, chlorine, hydroxy, methoxy, ethoxy, methyl or amino or,R.sub.1 may further stand for hydroxy, in this case the compound of the formula I may exist according to the conditions in the form of tautomers of the formula Ia ##STR4## and R.sub.1 may further stand for benzyl, 2,2-diphenylethyl or theophyllin-7-yl-methyl.