| abstract |
Compounds of general formula (1) are described wherein Y is a halogen atom or a group -OR1, where R1 is an optionally substituted alkyl group; X is -O-, -S- or -N(R8)-, where R8 is a hydrogen atom or an alkyl group; R2 is an optionally substituted alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R3 is a hydrogen or halogen atom or an -OR9 group, where R9 is a hydrogen atom or an optionally substituted alkyl, alkenyl, alkoxyalkyl, or alkanoyl group, or a formyl, carboxamido or thiocarboxamido group; R?4 and R5¿, which may be the same or different, is each a group -(CH¿2?)nAr, where Ar is a monocyclic or bicyclic aryl group optionally containing one ore more heteroatoms selected from oxygen, sulphur or nitrogen atoms and n is zero or an integer 1, 2 or 3; R?6¿ is a hydrogen atom or an optionally substituted alkyl group; R7 is a hydrogen atom or an optionally substituted alkyl group; and the salts, solvates, hydrates and N-oxides thereof. Compounds according to the invention are potent, selective and orally active PDE IV inhibitors and are useful in the prophylaxis and treatment of asthma and other diseases. |