A compound of formula I: wherein A is a connecting chain of (C1-3) alkyl; B is O or S; R1 is H, (C1-6) alkyl, halo, CF3, or OR1a wherein R1a is H or (C1-6)alkyl; R2 is H or Me; R3 is H or Me; R4 is H, (C1-4) alkyl, (C3-4) cycloalkyl and (C1-4)alkyl(C3-7)cycloalkyl; W is selected from  wherein, a) one of Y is SO2 and the other Y is NR5, provided that both are not the same, wherein R5 is H, (C1-6)alkyl,(C3-6) cycloalkyl, the alkyl being substituted, COR5o, COOR5p or CONR5pPR5q; and each R8 is H, (C1-4) alkyl, (C3-6) cycloalkyl, or (C1-4) alkyl-(C3-6) cycloalkyl; or b) E is CR8aR8b wherein R8a and R8b is H, or alkyl and J is CH2; or J is CR8aR8b and E is CH2, and the dotted line represents a single bond; or c) E is C(O) and J is CR8aR8b or J is C(O) and E is CR8aR8b and the dotted line represents a single bond; or d) E and J are CR8aR8b and the dotted line represents a double bond. Compounds of formula I have activity against HIV WT and double mutant strains.