A Facile Synthesis of 5′-<i>O</i>,6-Cyclo-5,5-dihalogeno-5,6-dihydropyrimidine Nucleosides

Abstract

Treatment of 2′,3′-O-isopropylidenepyrimidine nucleosides (1; uridine and cytidine) with excess N-halogenosuccinimides in an aprotic solvent at ambient temperature results in the exclusive formation of the corresponding 5′-O,6-cyclo-5, 5-dihalogeno-5,6-dihydro-2′,3′-O-isopropylidenepyrimidine nucleosides 2.