Regioselectivity of the hydrolysis of 2-(1-alkoxyvinyl)-substituted imidazolidines, 1,3-thiazolidines, and 1,3-oxazolidines

Autor: Nadezhda V. Vchislo, N. A. Keiko, E. A. Funtikova, Lyudmila I. Larina, Yu. L. Frolov
Rok vydání: 2011
Předmět:
Zdroj: Russian Journal of Organic Chemistry. 47:1832-1840
ISSN: 1608-3393
1070-4280
Popis: 2-(1-Alkoxyvinyl)-1,3-thiazolidines reacted with H2O or D2O in the presence of 105 mol % of p-toluenesulfonic acid or trifluoroacetic acid (20°C, 1 h) to give 2-acetyl-1,3-thiazolidine in quantitative yield. 2-(1-Alkoxyvinyl)-3,5-diphenylimidazolidines underwent hydrolysis in the presence of 20 mol % of an acid (20°C, 24 h) at the vinyloxy group with high regioselectivity yielding 2-acetylimidazolidines. Hydrolysis of 2-(1-alkoxyvinyl)-3-phenyl-1,3-oxazolidines in the presence of 10 mol % of p-toluenesulfonic acid (20°C, 5 days) takes two pathways, one of which involves the endocyclic C-O bond with ring opening and the other involves the vinyloxy group to produce 2-acetyl-3-phenyl-1,3-oxazolidine. Unlike phenyl-substituted 1,3-thiazolidines and imidazolidines, hydrolysis of their 3-methyl- and 3,5-dimethyl-substituted analogs in acid medium occurs mainly via ring opening. The observed hydrolysis pathways were interpreted in terms of B3PW91/6-311G(d,p) quantum-chemical calculations.
Databáze: OpenAIRE
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