Patent ID: 6075143
Filing Date: 2000-06-13
Classification: C07D,Y02P

Abstract:
A compound of the formula I or a salt thereof ##STR11## in which PG is a trityl type protective group which is labile to weak acids, and is selected from triphenylmethyl (Trt), (4-methoxyphenyl)-diphenylmethyl (Mmt), (4-methylphenyl)-diphenylmethyl (Mtt), di-(4-methoxyphenyl)phenylmethyl (Dmt) and 9-(9-phenyl)xanthenyl (pixyl);X is NH, O or S;Y is CH.sub.2, NH or O, andB' is a base selected from adenine, cytosine, guanine, thymine, uracil, purine, 2,6-diaminopurine, 7-deazaadenine, 7-deazaguanine, N.sup.4 N.sup.4 -ethanocytosine, N.sup.6 N.sup.6 -ethano-2,6-diaminopurine, 5-methylcytosine, 5-(C.sub.2 -C.sub.6)alkynyluracil 5-(C.sub.2 -C.sub.6)alkynylcytosine, 5-fluorouracil and pseudoisocytosine, wherein any exocyclic amino or hydroxyl group is protected by a protective group, or B' is further selected from imidazole, triazole, and nitroimidazole.