| abstract |
Aromatic heterocyclic derivatives have the formula ##STR1## wherein R 1 represents ##STR2## wherein R 3 represents hydrogen, --OR 4 wherein R 4 represents hydrogen, alkyl having 1-20 carbon atoms or mono- or polyhydroxyalkyl or R 3 represents ##STR3## wherein r' and r" represent hydrogen, lower alkyl or together form a heterocycle, R 2 represents hydrogen or --CH 3 and Ar represents ##STR4## wherein Z is O or S, ##STR5## wherein R 5 is lower alkyl or ##STR6## wherein R 6 is hydrogen or alkyl having 1-10 carbon atoms and R 7 represents alkyl having 4-12 carbon atoms or cycloalkyl, Y is CH or a nitrogen atom and X represents oxygen, sulfur or --N--R 8 when R 8 represents hydrogen, lower alkyl or lower alkoxycarbonyl, with the proviso that (i) when Y is CH and X is oxygen or sulfur Ar is other than C and (ii) when Y is nitrogen and X is oxygen, Ar is other than (C) or (D) in which R 6 is alkyl having 1-4 carbon atoms and R 7 is branched alkyl having 4-12 atoms useful in veterinary or human therapy and in cosmetic formulations. |