Patent ID: 7105542

Claim:
A compound of formula A: wherein X is selected from the group consisting of O, N, S, SO, and SO 2 ; R 1 and R 2 can be the same or different and are selected from the group consisting of H, OH, OCH 3 , OCH 2 CH 3 , OCH 2 CH 5 , NH 2 , NHCH 3 , N(CH 3 ) 2 , CN, CH 3 , CH 2 CH 3 , CH 2 CH 2 CH 3 , CH(CH 3 ) 2 , C(CH 3 ) 3 , NO 2 , F, Cl, Br, CF 3 , SH, SCH 3 , SCH 2 CH 3 , OCOCH3, OCOC(CH 3 ) 3 , and OCOCH 2 COOH; R 3 is