| abstract |
The present invention relates to compounds of formula (I) and the pharmaceutically acceptable salts thereof, wherein X is O, S or NH; R and R<1> are each independently selected from H and C1-C4 alkyl or taken together represent C2-C6 alkylene; R<2> is H or C1-C4 alkyl; R<3> is a) a 6-membered heterocyclic ring containing 1 or 2 N heteroatoms linked to X by a ring carbon atom and optionally benzofused and optionally substituted, b), when X is NH, a group of formula (i), or c) when X is NH, a group offormula (j); and R<4> is phenyl substituted by a hydroxy group and optionally further substituted, by 1 or 2 substituents; together with compositions containing, uses of, processes for the preparation of and intermediates used in the preparation of such compounds. |