3-Hydroxypyrroles and 1H- pyrrol-3(2H)-ones. Part 10. Alkylation of pyrrolones under basic conditions: regiospecific formation of 3-alkoxypyrroles
作者:Gordon A. Hunter、Hamish McNab、Lilian C. Monahan、Alexander J. Blake
DOI:10.1039/p19910003245
日期:——
Alkylation of 1 -substituted 1 H-pyrrol-3(2H)-ones 1 in the presence of base generally gives a mixture of O-alkylated 3, C, O-dialkylated 4 and C, C-dialkylated 5 products. The proportion of C-alkylation is increased by the use of a soft alkylating agent (e.g. iodomethane) and a solvent of low polarity (e.g. THF), whereas O-alkylation is favoured by hard alkylating agents (e.g. methyl toluene-psulphonate)
Simple 3-hydroxypyrroles are obtained by pyrolysis of appropriate aminomethylene Meldrum's acid derivatives: the unusual reactions of these compounds with acids, bases, and electrophiles is discussed.
3-Hydroxypyrroles and 1H-pyrrol-3(2H)-ones. Part 9. Diazo-coupling reactions of 1-substituted-1H-pyrrol-3(2H)-ones
作者:Alexander J. Blake、Hamish McNab、Lilian C. Monahan
DOI:10.1039/p19910000701
日期:——
Reaction of the 1-substituted 1H-pyrrol-3(2H)-ones 6 and 7 with diazonium salts under acidic conditions gives rise to 2-coupled products, which are shown by X-ray crystallography to adopt the ketohydrazone structures 9–11K.