ormula L1; and A is a group of the formula A1 where one of E1 and E2 is hydrogen and the other is hydrogen, tert-butoxycarbonyl or benzyloxycarbonyl; and one of X and Y is CH and the other is CH or N and W1 is NH, lower-alkyl-N or lower-alkoxy-lower-alkyl-N; and Q is O;as well as hydrates or solvates and physiologically usable salts thereof. 2.