Abstract: There are described compounds of formula I, ##STR1## in which Ra, Rb, Rc, Rd, Re, Rf and Rg, which may be the same or different, each represent hydrogen, amino, hydroxy, alkoxy, alkenyloxy, halogen, acyl, alkenyl, alkyl, or alkoxy substituted by phenyl,Rh is hydrogen, alkyl or --COOH.X is a hydrocarbon chain containing from 2 to 10 carbon atoms and optionally substituted by a hydroxy group,A has no significance or represents Y, OY, or SY and Y represents a C 1 to 4 hydrocarbon chain which is optionally substituted by alkyl C 1 to 4,E and G, which may be the same or different, each represent --O--, --S-- or --CH.sub.2 --, provided that at least one of E and G is --O-- or --S--,L, together with the carbon atoms to which it is attached, forms a benzene, furan, thiophene, pyrrole, or pyran-2-one ring,and pharmaceutically acceptable derivatives thereof.

Abstract: There are described compounds of formula I, ##STR1## in which Ra, Rb, Rc, Rd, Re, Rf and Rg, which may be the same or different, each represent hydrogen, amino, hydroxy, alkoxy, alkenyloxy, halogen, acyl, alkenyl, alkyl, or alkoxy substituted by phenyl,Rh is hydrogen, alkyl or --COOH.X is a hydrocarbon chain containing from 2 to 10 carbon atoms and optionally substituted by a hydroxy group,A has no significance or represents Y, OY, or SY and Y represents a C 1 to 4 hydrocarbon chain which is optionally substituted by alkyl C 1 to 4,E and G, which may be the same or different, each represent --O--, --S-- or --CH.sub.2 --, provided that at least one of E and G is --O-- or --S--,L, together with the carbon atoms to which it is attached, forms a benzene, furan, thiophene, pyrrole, or pyran-2-one ring,and pharmaceutically acceptable derivatives thereof.