A compound of formula I ** Formula ** in which R1 is hydrogen, halogen, hydroxy, alkoxy or cyano； each of Y1 and Y2 represents CH and one or two of U, V, W and X represents (n) N, and each of the remaining represents CH or, in the case of X, can also represent CRa, and, in in the case of W, it can also represent CRb, or each of U, V, W, X, Y1 and Y2 represents CH, or each of U, V, W, X and Y1 represents CH and Y2 represents N, or also one or, with the proviso that R1 is hydrogen, two of U, V, W, X, Y1 and Y2 represent CRc and each of the remaining represents CH； Ra represents halogen； Rb represents alkoxy, alkoxycarbonyl or alkoxyalkoxy； Rc, each time it appears, independently represents hydroxy or alkoxy； A is CH2CH (OH), CH2CH (NH2), CH (OH) CH (NH2) or CH (NH2) CH2, B is CH2CH2, CH2NH or CONH and D is CH2, or A is CH (OH) CH2 and B is CH2CH2, CH2NH, N (R2) CO, CONH or N (R2) CH2 and D is CH2 or B is N (R2a) CH2 and D is CH (OH), or A is CH (OH) CH (OH), B is CH2NH or CONH and D is CH2, or A is CH2CH2 and B is CH2CH2, NR4aCH2, CH2NR3, NHCO, CONR4, CH2O, CH (OH) CH2, CH2CH (OH), CH (NHR3a) CH2, COCH2 or CH2CH2NH and D is CH2 or B is CH2NH and D is CO, or also A is CH2CH2, B is NR4bCH2 or CH2CH2 and D is CH (OH), or A is CH>； = CH, B is CH2NR5, CONR6 or CH2O and D is CH2, or A is C≡C, B is CH2NH and D is CO, or A is CH2CO, B is NHCH2 and D is CH2, or A is COCH2, B is CH2CH2 or CONH and D is CH2, or A is CH2N (R7) and B is CH2CH2, COCH2 or CH2CH (OH) and D is CH2 or B is CH2CH2 or CH2CH (OH) and D is CH (OH) or CH (NH2), or A is CONH or CH2O, B is CH2CH2 and D is CH2, or A is NHCH2 and B is CH2CH2 or CH2NH and D is CH2, or B is CH2NH and D is CO, or A is NHCO, B is CH (R8) NH or CH2CH2 and D is CH2, or A is OCH2, B is CH2, CH2CH2, CH>； = CH or CONH and D is CH2； R2 is hydrogen or alkyl； R2a is hydrogen or alkyl； R3 is hydrogen, phenylalkyl, CO- (CH2) p-COOR3 ', (CH2) p-COOR3', acyl or aminoalkyl, or R3 is alkyl which may be substituted once or twice by hydroxy gr
