2'-ALKYLIDENEPYRIMIDINE NUCLEOSIDE DERIVATIVES, PROCESS FOR THEIR PREPARATION, AND THEIR USE.

摘要

pyrimidine nucleosides of formula (I) and their salts are new: where R1 is amino or OH; R2 is H, halogen or lower alkyl; R3 is H or lower alkyl; R4 is H or a phosphate residue. Preferred are (I) where R3=H, and especially where R3=H and R2 is H, halogen or Me. Most preferred are (I) where R2=R3=H and R1 is amino; and where R1=OH, R2=Me and R3=H. (I) are prepd. from cpds. (II) where Z is a hydroxyl-protecting group; R5 is alkoxy, OH, amino or acylamino) by Wittig alkylidenation using for example Ph3P=CHR3, followed by removal of protecting groups and opt. phosphorylation.