CHEMICAL PROCESS

摘要

The present invention relates to compounds of the general formula I and salts thereof - wherein R stands for hydrogen or C1-4 straighed or branched chain alkyl, which are prepared by a) reacting a compound of the general formula II - wherein X stands for halogen or sulphonic acid ester - with a compound of the general formula III - wherein R stands as given above - or b) reacting a salt of the compound of the general formula III - wherein R is as given above - with a compound of the general formula II - wherein X is halogen or sulphonic acid ester group. The compounds of the formula I are used as cough relievers.