The determinative influence of the O6-(diphenylcarbamoyl) group on the exocyclic nitrogen benzylation in 2-amino-6-oxopurine derivatives
A series of novel 2-(benzylamino)-6-oxopurine derivatives has been synthesized by arylalkylation of the corresponding 2-(acetylamino)-6- (diphenylcarbamoyloxy)purines. The decisive role of the temporary O 6-(diphenylcarbamoyl) protection on the benzylation of the exocyclic amino group in 2-(acetylamino)-6-oxopurines has been demonstrated. Georg Thieme Verlag Stuttgart.
Madre, Marina,Petrova, Marina,Belyakov, Sergey
experimental part
p. 3053 - 3060
(2009/04/06)
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 the 7/9 isomer mixtures. Per(trimethylsilyl)-2-N-acyl-6-O-(diphenylcarbamoyl)guanine derivatives and tetra-O-acylpentofuranoses underwent regioselective coupling (trimethylsilyl trifluoromethanesulfonate catalysis) to give 9-glycosylguanines. The 6-O-(diphenylcarbamoyl)peracyl-9-β-D-ribofuranosyl isomer was shown to be both the xinetic 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.
Robins, Morris J.,Zou, Ruiming,Guo, Zhiqiang,Wnuk, Stanislaw F.
p. 9207 - 9212
(2007/10/03)
High-yield regioselective synthesis of 9-glycosyl guanine nucleosides and analogues via coupling with 2-N-acetyl-6-O-diphenylcarbamoylguanine
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Zou,Robins
p. 1436 - 1437
(2007/10/02)
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