wherein Z1 is (CH2)q or C═O; Z2 is (CH2)p or C═O; D is —CH═ or C═O or (CH2)m where m is 0, 1, 2 or 3; n=0, 1 or 2; p=1 or 2; q=0, 1 or 2; Q is C or N; A is (CH2)x where x is 1 to 5, or A is (CH2)x1, where x1 is 1 to 5 with an alkenyl bond or an alkynyl bond embedded anywhere in the chain, or A is —(CH2)x2—O—(CH2)x3— where x2 is 0 to 5 and x3 is 0 to 5, provided that at least one of x2 and x3 is other than 0; B is a bond or is (CH2)x4 where x4 is 1 to 5; X is CH or N; X2 is C, N, O or S; X3 is C, N, O or S; X4 is C, N, O or S; X5 is C, N, O or S; X6 is C, N, O or S; provided that at least one of X2, X3, X4 X5 and X6 is N; and at least one of X2, X3, X4 X5 and X6 is C. R1 is H or alkyl; R2 is H, alkyl, alkoxy, halogen, amino, substituted amino or cyano; R2a, R2b and R2c may be the same or different and are selected from H, alkyl, alkoxy, halogen, amino, substituted amino or cyano; and R3, E, Z and Y are as defined herein.