Patent ID: 7087591

Claim:
A compound having the formula in which: R 1 is a member selected from the group consisting of —OCH 3 , —SCH 3 , —N(CH 3 ) 2 , —NHCH 3 , —CHO, —COCH 3 and —CHOHCH 3 ; R 2 is a member selected from the group consisting of halogen, alkyl, acyl, hydroxy, alkoxy, acyloxy, alkylcarbonate, cypionyloxy, S-alkyl and S-acyl; R 3 is a member selected from the group consisting of alkyl, hydroxy, alkoxy and acyloxy; R 4 is a member selected from the group consisting of hydrogen and alkyl; and X is a member selected from the group consisting of ═O and ═N—OR 5 , wherein R 5 is a member selected from the group consisting of hydrogen and alkyl.