A NOVEL SYNTHESIS OF DOUBLE-HEADED NUCLEOSIDES VIA REVERSED NUCLEOSIDES

The ''double headed' nucleosides 10, 11 and 13 bearing pyrimidine or p urine bases attached on C-1 and C-5 positions of single ribose unit ha ve been synthesized following a new synthetic strategy. The strategy r ests on the introduction of the first nucleo base at C-5 position of t he ribose unit giving 'reversed' nucleoside and the subsequent attachm ent of the second base at C-1 position of the ribose, by classical gly cosylation reaction. This order of the base attachments gave much bett er yields on the ''double headed' nucleosides then previously known C- 1 then C-5 order of attachments.