Patent ID: 7371741

Claim:
A compound of the general formula: wherein R a is selected from —OCH 3 ; —OCH 2 CH 3 ; or —CCCH 3 ; Z′ is selected from >C—F, >C—NH 2 , >CCONH 2 , >C—NHCOH, >C—OSO 2 NH 2 , or >C—CHCH 2 , and Z″ is selected from >C(H 2 ), >C(H)—CH 3 , >C═CH 2 , >C═CHCH 3 , or >C═O; provided that when Z′ is >C—OSO 2 NH 2 and Z″ is >C(H 2 ), >C(H)—CH 3 , >C═O, >C═CH 2 or >C═CHCH 3 , R a is neither —OCH 3 nor —OCH 2 CH 3 , and when Z′ is >C—NH 2 , Z″ is not >C═O and provided that Z′ is not >C—NH 2 when R a is —OCH 3 or —OCH 2 CH 3 and Z″ is >C(H 2 ).