GR76444

N-Substituted azaheterocyclic carboxylic acids and their esters, of the formula:- wherein: n is a positive whole integer 2, 3 or 4; m is zero; R4 is hydrogen, or lower alkyl of from 1 to 4 carbon atoms; the dotted line represents an optional bond; R5 is hydrogen, or hydroxy, or when the dotted line forms a double bond, hydrogen; B is wherein R1 is hydrogen, fluorine, chlorine, methyl or methoxy; Y is -C(A)=C(R3)-, -CH -CHR3- in which case n is 3 or 4, or -C IDENTICAL C-, wherein R2 is hydrogen, fluorine, chlorine, methyl or methoxy, R3 is hydrogen or methyl, and A is 2-thienyl, 3-thienyl or cyclohexyl; or B-Y is (cyclohexyl)2C=C(R3)-; or when Y is a -C(A)=C(R3)- m may also be one: or a pharmaceutically acceptable acid addition salt thereof, useful as inhibitors of GABA uptake, are prepared by reacting an appropriate N-alkylating derivative with an ester of an N-unsubstituted azaheterocyclic carboxylic acid followed by hydrolysis of the ester.