Patent ID: 6900308

Claim:
A compound of formula I wherein: Y 1 is S and Y 2 is NHR 1 ; or Y 1 is Se and Y 2 is SH; Y 3 is NHR 1 , OH, C 1 -C 12 alkyl, or C 1 -C 12 O-alkyl; R 1 is hydrogen, substituted or unsubstituted C 1 -C 12 alkyl, substituted or unsubstituted C 2 -C 12 alkenyl, substituted or unsubstituted C 2 -C 12 alkynyl, substituted or unsubstituted C 5 -C 20 aralkyl, substituted or unsubstituted C 5 -C 20 alkylaryl, substituted or unsubstituted C 5 -C 20 heterocycloalkyl, substituted or unsubstituted C 5 -C 20 aryl, substituted or unsubstituted C 5 -C 20 heteroaryl, said substituted moieties comprising one or more substituents selected from hydrogen, halo, C 1 -C 12 alkyl, C 2 -C 12 alkenyl, C 2 -C 12 alkynyl, C 5 -C 20 aryl, C 1 -C 12 alkoxy, alkoxyalkyl, O-alkylaminoalkyl, O-alkylimidazolyl, S-alkyl, amino, alkylamino, dialkylamino, arylamino, diarylamino, C 5 -C 20 aryl, C 5 -C 20 heteroaryl, C 1 -C 12 cycloalkyl, C 1 -C 12 heterocyclolalkyl, O-aryl, S-aryl, O-aralkyl, S-aralkyl, NH-aralkyl, nitro, cyano, aldehyde, carboxylic acid, hydroxy, alkylcarbonyl, aminocarbonyl, or mercapto; Bx is an optionally protected heterocyclic base moiety; one of X 1 and X 2 is H, hydroxyl, a protected hydroxyl, or a sugar substituent group and the other of X 1 and X 2 is hydroxyl, a protected hydroxyl, azido, or -O-J-SM; J is a bifunctional linking moiety, selected from the group consisting of hydroxyl, acyl, amino, alkoxy, carboxy, benzyl, phenyl, nitro, thiol, thioalkoxy, halogen, alkyl, aryl, alkenyl and alkynyl; and SM is a solid support medium.