Patent ID: 7202361

Claim:
A compound of the formula: wherein: the substituent groups defined by R 1 , R 2 are each independently selected of H, C(═O)R′, C 1 –C 18 alkyl, C 2 –C 18 alkenyl, C 2 –C 18 alkynyl, or aryl; each of the R′ groups is independently selected from the group consisting of H; OH; NO 2 ; NH 2 ; SH; CN; halogen; ═O; C(═O)H; C(═O)CH 3 ; CO 2 H; or C 1 –C 18 alkyl, C 2 –C 18 alkenyl, or C 2 –C 18 alkynyl, each of which, independently, may be substituted with one or more substituents selected from the group consisting of halogen, cyano, hydroxy, nitro, azido; alkanoyl, carboxamido, alkyl, alkenyl, alkynyl, aryloxy, alkoxy, alkylthio, alkylsulfinyl, alkylsulfonyl, carbocylic aryl having 6 or more carbons, and aralkyl; or unsubstituted aryl; X 2 is OX 1 or N(X 1 ) 2 wherein each X 1 is independently H, C(═O)R′ where R′ is as defined, unsubstituted C 1 –C 18 alkyl, C 2 –C 18 alkenyl, C 2 –C 18 alkynyl, aryl, alkoxy, heterocyclyl, or two X 1 groups together form a cyclic substituent on the nitrogen atom, or X 1 is SO 2 CH 3 when X 2 is OX 1 , or N(X 1 ) 2 is NHCOalkylCOOH, NHbiotin, NH(aa) y where aa is amino acid acyl and y is 1, 2 or 3 optionally with a amide terminal group, protected NHCOCH(NH 2 )CH 2 SH, NHCOalkenylaryl substituted with CF 3 , or m-methoxycarbonylbenzoylNH; wherein N(X 1 ) 2 is not NH 2 ; X 3 is selected of OR 1 where R 1 is as defined, CN, (═O), or H; X 4 is —H or C 1 –C 18 alkyl; and X 5 is selected of H, or R 1 where R 1 is as defined; with the exception of compounds 14 and 47 of U.S. Pat. No. 5,721,362.