A synthetic approach to chiral carbocyclic nucleosides of varied ring-sizes using carbon framework of D-glucose

Abstract

Synthesis of enantiomerically pure carbocyclic nucleoside analogues 10-16 with five-, six-and seven-membered rings has been achieved starting from D-glucose derived tetracyclic isoxazolidinocarbocycle precursors 1-3. Cyclization of 6-chloro pyrimidine derivatives 7-9 to purine derivatives was found to be accomplished by nucleophilic displacement of 6-chloro substituent (by dimethylamino and/or methoxy groups). Apparently, hydrogen bonding between N-3 of the purine ring and a hydoxy substituent at C-2 / plays a crucial role in this transformation.