113575-01-2Relevant academic research and scientific papers
Direct Synthesis of Pyrrole Nucleosides by the Stereospecific Sodium Salt Glycosylation Procedure
Ramasamy, Kandasamy,Robins, Roland K.,Revankar, Ganapathi R.
, p. 863 - 868 (2007/10/02)
A stereospecific high-yield glycosylation of preformed fully aromatic pyrroles has been accomplished for the first time.Reaction of the sodium salt of pyrrole-2-carbonitrile (1a) and pyrrole-2,4-dicarbonitrile (1b) with 1-chloro-2-deoxy-3,5-di-O-p-toluoyl-α-D-erythro-pentofuranose (2) gave exclusively the corresponding blocked nucleosides with β-anomeric configuration 3a and 3b, which on deprotection gave 1-(2-deoxy-β-D-erythro-pentofuranosyl) derivatives of 1a (3c) and 1b (3d).Functional group transformation of 3c and 3d provided a number of 2-monosubstituted 4a-c and 2,4-disubstituted 4d-f derivatives of 1-(2-deoxy-β-D-erythro-pentofuranosyl)pyrrole.Similar glycosylation of the sodium salt of 1a and 1b with 1-chloro-2,3,5-tri-O-benzyl-α-D-arabinofuranose (5) and further functional group transformation of the intermediate blocked nucleosides 6a and 6b provided 1-β-D-arabinofuranosyl derivatives of pyrrole-2-carboxamide (7b) and pyrrole-2,4-dicarboxamide (7d).The synthetic utility of this glycosylation procedure for the preparation of 1-β-D-ribofuranosylpyrrole-2-carbonitrile (12) has also been demonstrated by reacting the sodium salt of 1a with 1-chloro-2,3-O-isopropylidene-5-O-(t-butyl)dimethylsilyl-α-D-ribofuranose (1O) and subsequent deprotection of the blocked intermediate 11.This study provided a convenient route to the preparation of aromatic pyrrole nucleosides.
