Patent ID: 7109331

Claim:
A compound of the formula: wherein: A is CH or CR, where R is selected from halogen, optionally substituted alkyl, aralkyl and aryl, OH, NH 2 , NHR 1 , NR 1 R 2 and SR 3 , where R 1 , R 2 and R 3 are each optionally substituted alkyl, aralkyl or aryl groups; B is OH; D is selected from OH, NH 2 , NHR 5 , H, halogen and SCH 3 , where R 5 is an optionally substituted alkyl, aralkyl or aryl group; X and Y are independently selected from H, OH and halogen, with the proviso that when one of X and Y is hydroxy or halogen, the other is hydrogen; Z is OH, or, when X is hydroxy, Z is selected from hydrogen, halogen, hydroxy, SQ and OQ, where Q is an optionally substituted alkyl, aralkyl or aryl group; and W is OH or H, with the proviso that when W is OH, then A is CR where R is as defined above; or a tautomer thereof; or a pharmaceutically acceptable salt thereof.