| abstract |
Compounds of formula IB wherein B is a pentagonal heterocyclic group chosen from formulas (a), (b), (c) and (d) R1 means hydrogen or lower C1-C7; R2 means hydrogen, C1-C7 alkyl, C1-C7 alkoxy, halogen or trifluoromethyl; X means O, S or two hydrogen atoms that do not form a bridge; A1 and A2 mean, independently of each other, phenyl or a 6-membered heterocycle containing 1 or 2 nitrogen atoms; R4 and R5 mean hydrogen, C1-C7 alkyl, C1-C7 alkoxy, cyclohexyl, C1-C7 alkylcyclohexyl or trifluoromethyl, with the proviso that at least one of R4 or R5 must be hydrogen; as well as its pharmaceutically acceptable salts. |