| abstract |
A compound of formula I ** Formula ** in which R1a represents H or carboxy and R1b represents H, or R1a and R1b together represent the group * -C (O) -NH-S- or the group * -C (OH )> = NS-, in which "*" represents the junction point of R1a and "" represents the junction point of R1b; R2 represents H, (C1-C3) alkyl, hydroxy (C1-C3) alkyl, benzyl or cycloalkyl (C3-C5); R3 represents H or halogen; U represents N or CR4; wherein R4 is H or (C1-C3) alkoxy; A represents CH, B represents NH, m represents 1 or 2 and n represents 1 or 2; or A represents N, B is absent, m represents 2 and n represents 2; Y represents CH or N; and Q represents O or S; or a salt of said compound. |