Patent ID: 7754718

Claim:
An isolated compound of the formula: Where R 1 and R 2 together with the adjacent benzene ring form a 6-membered heterocyclic ring according to the structure Ia: where Y is a —N(R 7 )—N(R 8 )— group; X 1 and X 2 are each a C═O group; R 7 and R 8 are each independently H or a C 1 -C 6 alkyl group which may be optionally substituted with a hydroxyl group; R a and R b together form a —(CH 2 ) k — group; k is 1 or 2; R 13 is H, OH, —O(C 1 -C 4 )alkyl, (C 1 -C 4 ) alkyl; and R 15 is H, OH, —O(C 1 -C 4 )alkyl, (C 1 -C 4 ) alkyl, F, Cl, Br or I; or their anomers or pharmaceutically acceptable salts thereof.