| abstract |
Compounds of general formula (1) <IMAGE> (1) are described wherein Y is a halogen atom or a group -OR1, wherein R1 is an optionally substituted alkyl group; X is -O-, -S- or -N(R6)-, where R6 is a hydrogen atom or an alkyl group; R2 is an optionally substituted alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R3 and R4, which may be the same or different, is each a group -(CH2)nAr, where Ar is a monocyclic or bicyclic aryl group optionally containing one or more heteroatoms selected from oxygen, sulphur or nitrogen atoms and n is zero or an integer 1, 2 or 3; R5 is a hydrogen atom or an optionally substituted alkyl group; and the salts, solvates, hydrates and N-oxides. Compounds according to the invention are potent, selective and orally active PDE IV inhibitors and are useful in the prophylaxis and treatment of asthma. |