Patent ID: 8497385

Claim:
A compound of Formula I wherein: X is S, N(optionally substituted alkyl), N(optionally substituted alkenyl), N(optionally substituted alkynyl), N(optionally substituted aryl), N(optionally substituted heteroaryl), N(optionally substituted aralkyl), or N(optionally substituted heteroaralkyl), R 3 is H or OH; R 7 is selected from the group consisting of optionally substituted lower alkyl, optionally substituted alkenyl, hydroxyl, amino, optionally substituted alkylamino, ═O, optionally substituted acylamino, OC(O)NR′R′, OC(O)OR′, OC(O)R′, and substituted acyloxy; p is 1, 2, 3, or 4; R 20 is H, OH, or -T-U—V—R′ where: T is selected from —O—, —S—, —N(H)— or —N(Me)—; U is absent or is selected from —C(O)—, —C(S)—, —S(O)— or —S(O) 2 —; and V is absent or is selected from —O—, —S—, —N(H)— or —N(Me)—, provided that V is absent when U is absent; R 21 is ═CR a R b or R 21 represents independent moieties R c and R d where: R a and R b are independently H, CO 2 R′, CONR c R d or R′; R c and R d are independently H, alkyl, alkenyl or alkynyl, or (CH 2 ) n CO 2 R′ where n is 1, 2 or 3; R 26 is H or R′; and R′ is independently selected from the group consisting of H, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted aralkyl, optionally substituted heteroaralkyl, and their pharmaceutically acceptable salts thereof; or wherein: X is O, R 3 is H or OH; R 7 is selected from the group consisting of optionally substituted alkenyl, OC(O)NR′R′, and OC(O)OR′; p is 1, 2, 3, or 4; R 20 is H, OH, or -T-U—V—R′ where: T is selected from —O—, —S—, —N(H)— or —N(Me)—; U is absent or is selected from —C(O)—, —C(S)—, —S(O)— or —S(O) 2 —; and V is absent or is selected from —O—, —S—, —N(H)— or —N(Me)—, provided that V is absent when U is absent; R 21 is ═CR a R b or R 21 represents independent moities R c and R d where: R a and R b are independently H, CO 2 R′, CONR c R d or R′; R c and R d are independently H, alkyl alkenyl, or alkynyl, or (CH 2 ) n CO 2 R′ where n is 1, 2 or 3; R 26 is H or R′; and R′ is independently selected from the group consisting of H, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted aralkyl, optionally substituted heteroaralkyl, and their pharmaceutically acceptable salts thereof.