Nucleic acid related compounds .93. A solution for the historic problem of regioselective sugar-base coupling to produce 9-glycosylguanines or 7-glycosylguanines

Per(trimethylsilyl)-2-N-acylguanine derivatives and tetra-O-acylpentofuranoses were coupled [tin-(IV) chloride or titanium(IV) chloride catalysis] to give predominant formation of 7-glycosylguanines. With TiCl4, a fortuitous organic/aqueous partitioning allowed isolation of 7-glycosylguanines from t...

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Published inJournal of organic chemistry Vol. 61; no. 26; pp. 9207 - 9212
Main Authors Robins, MJ, Zou, RM, Guo, ZQ, Wnuk, SF
Format Journal Article
LanguageEnglish
Published WASHINGTON Amer Chemical Soc 27.12.1996
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
GUANINE NUCLEOSIDES
GUANOSINE ANALOGS
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Summary:Per(trimethylsilyl)-2-N-acylguanine derivatives and tetra-O-acylpentofuranoses were coupled [tin-(IV) chloride or titanium(IV) chloride catalysis] to give predominant formation of 7-glycosylguanines. With TiCl4, a fortuitous organic/aqueous partitioning allowed isolation of 7-glycosylguanines from the 7/9 isomer mixtures. Per(trimethylsilyl)-2-N-acyl-6-O-(diphenylcarbamoyl)guanine derivatives and tetra-O-acylpentofuranoses underwent regioselective coupling (trimethylsilyl trifluoromethane-sulfonate catalysis) to give 9-glycosylguanines. The 6-O-(diphenylcarbamoyl)peracyl-9-beta-D-ribofuranosyl isomer was shown to be both the kinetic and thermodynamic coupling product. Deprotection of all of the peracyl coupling products was effected under mild conditions to give good to high yields of guanine nucleoside analogues. These methodologies provide solutions for the regioselective synthesis of 7- and 9-glycosylguanine nucleosides.
ISSN:0022-3263
DOI:10.1021/jo9617023