Patent ID: 8198290

Claim:
A compound of Formula I, or a salt thereof: wherein R 1 and R 2 are independently selected from the group consisting of H, —CH 3 , —C 2 H 5 , —CH 2 Ph, Ph, t-Bu, —CH 2 CH 2 Si(CH 3 ) 3 , —CH 2 CCl 3 , —CH 2 ═CHCH 2 , and —CH 2 CH 2 CN; X and Y are the same and are selected from the group consisting of: —OH, —OCH 3 , —OC 2 H 5 , or —OCH 2 Ph, or X and Y are taken together to form a cyclic group of —OCH 2 CH 2 O— or —OCH 2 CH 2 CH 2 O—, or X and Y are taken together to form an oxo group (═O); Z is H, R 3 -T- or R 4 —S—S-T-: T is selected from the group consisting of: —(CH 2 ) n —, —(CH 2 ) n —(OCH 2 CH 2 ) m —, —(CH 2 ) n —(OCH 2 CH 2 CH 2 ) m —, —CH 2 C(═O)NHO—(CH 2 ) n —, —CH 2 C(═O)NHO—(CH 2 ) n —(OCH 2 CH 2 ) m —, —CH 2 C(═O)NHO—(CH 2 ) n —(OCH 2 CH 2 CH 2 ) m —, —(CH 2 C(═O)NH) m —(CH 2 ) n —, —(CH 2 CH 2 C(═O)NH) m —(CH 2 ) n —, —(CH 2 ) n —(NHC(═O)CH 2 ) m —, —(CH 2 ) n —(OCH 2 CH 2 ) m —CH 2 NHC(O)—, and —(NHC(═O)CH 2 CH 2 ) m —, wherein n is an integer from 2 to 12, m is an integer from 1 to 6; R 3 is selected from the group consisting of: H 2 C═CH—, H 2 C═CHCH 2 O— HOCH 2 CH(OH)—, HOCH 2 CH(OH)CH 2 O—, HC≡C—, HC≡CCH 2 O—, (Ph) 3 CS—, HS—, Tr-S—, (HO) 2 B—, (PhO) 2 B—, (CH 3 O) 2 B—, CF 3 (CF 2 ) f (CH 2 ) g —, and —N 3 , wherein f is an integer from 1 to 11, g is 0 or an is an integer from 1 to 3; and R 4 is selected from the group consisting of: pyridine-2-yl, 5-nitropyridin-2-yl, N 3 -T-, HC≡C-T-, HC≡CCH 2 O-T-, CF 3 (CF 2 ) f (CH 2 ) g -T-, (HO) 2 B-T- and