Patent ID: 7560454

Claim:
A compound according to formula 1, or a pharmaceutically acceptable salt thereof, wherein: A is defined by formula 2 A 1 is CH 2 ; A 2 and A 3 are each CH; V 1 and V 2 are both H, OMe or F, or one of V 1 and V 2 is OH, OMe, benzyloxy, OPh, O-acyl, Br, Cl, F, N 3 , NH 2 , benzylamino or NH-acyl and the other is H, or V 1 and V 2 together are ═O, —S(CH 2 ) p S— or —(CH 2 ) p O—; W 1 is either O or S; X 1 and X 2 are both H, or together are ═O or ═S; Y is OR 5 or NR 6 R 7 ; Z is —CH═CH—; R 1 , R 2 , R 3 and R 4 are independently selected from H, lower alkyl, lower alkyloxy, F, Cl and Br; R 5 is selected from H and lower alkyl; R 6 and R 7 are independently selected from H and lower alkyl, or together are —(CH 2 ) n —; n=3, 4, 5 or 6; and p=2 or 3.