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A facile and improved synthesis of tubercidin and certain related pyrrolo[2,3‐ d ]pyrimidine nucleosides by the stereospecific sodium salt glycosylation procedure
Author(s) -
Ramasamy Kandasamy,
Imamura Nobutaka,
Robins Roland K.,
Revankar Ganapathi R.
Publication year - 1988
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570250652
Subject(s) - chemistry , sodium methoxide , pyrimidine , stereospecificity , trifluoroacetic acid , glycosylation , sodium , stereochemistry , enyne , salt (chemistry) , yield (engineering) , sodium salt , anomer , organic chemistry , catalysis , biochemistry , inorganic chemistry , materials science , metallurgy
A simple synthesis of tubercidin ( 1 ), 7‐deazaguanosine ( 2 ) and 2′‐deoxy‐7‐deazaguanosine ( 14 ) has been accomplished using the sodium salt glycosylation procedure. Reaction of the sodium salt of 4‐chloro‐ and 2‐amino‐4‐chloro‐pyrrolo[2,3‐ d ]pyrimidine, 3 and 4 , respectively, with 1‐chloro‐2,3‐ 0 ‐isopropylidene‐5‐ 0 ‐( t ‐butyl)dimethylsilyl‐α‐D‐ribofuranose ( 5 ) gave the corresponding protected nucleosides 6n and 7 with β‐anomeric configuration. Deprotection of 6 provided 8 , which on heating with methanolic ammonia gave tubercidin ( 1 ) in excellent yield. Functional group transformation of 7 , followed by deisopropylidenation gave 2‐aminotubercidin ( 10 ) and 2‐amino‐7‐β‐D‐ribofuranosylpyrrolo[2,3‐ d ]pyrimidine‐4(3 H )‐thione ( 11 ). Treatment of 7 with 1 N sodium methoxide followed by exposure to aqueous trifluoroacetic acid, and ether cleavage furnished 7‐deazaguanosine ( 2 ). 2′‐Deoxy‐7‐deazaguanosine ( 14 ) and 2′‐deoxy‐7‐deaza‐6‐thioguano‐sine ( 18 ) were also prepared by using similar sequence of reactions employing 4 and 1‐chloro‐2‐deoxy‐3,5‐di‐ O‐p ‐toluoyl‐α‐D‐ erythro ‐pentofuranose ( 15 ).