The activation of aminals and aminol ethers by sulfur dioxide and their reactions with electron rich aromatic compounds
摘要:
Reactions of bis(dialkylamino)methanes and ethoxydialkylaminomethanes with nucleophilic aromatic heterocycles in the presence of sulfur dioxide result in the formation of the expected Mannich bases in good yields. Reactions of phenols are similarly activated by sulfur dioxide which lead to improved regioselectivity: in particular the reactions of 2,5-dimethylphenol result in the formation of 2-dialkylaminomethyl-3,6-dimethylphenol whereas reaction occurs at the 4-position using the classical procedures. (C) 1997 Elsevier Science Ltd.
The effect of sulphur dioxide on the mannich reactions of phenols
作者:Robin A. Fairhurst、Harry Heaney、George Papageorgiou、Robert F. Wilkins
DOI:10.1016/s0040-4039(00)82196-6
日期:1988.1
Regioselectivity in the -dialkylaminomethylation of phenols is greatest, for example in reactions of 2,5-dimethylphenol, when a mixture of the phenol and sulphurdioxide is allowed to stand for several hours before the addition of a bis-(dialkylamino)methane (aminal) or an alkoxydialkylaminomethane (aminol ether).
The activation of aminals and aminol ethers by sulfur dioxide and their reactions with electron rich aromatic compounds
作者:Harry Heaney、George Papageorgiou、Robert F Wilkins
DOI:10.1016/s0040-4020(97)00848-x
日期:1997.9
Reactions of bis(dialkylamino)methanes and ethoxydialkylaminomethanes with nucleophilic aromatic heterocycles in the presence of sulfur dioxide result in the formation of the expected Mannich bases in good yields. Reactions of phenols are similarly activated by sulfur dioxide which lead to improved regioselectivity: in particular the reactions of 2,5-dimethylphenol result in the formation of 2-dialkylaminomethyl-3,6-dimethylphenol whereas reaction occurs at the 4-position using the classical procedures. (C) 1997 Elsevier Science Ltd.