A rapid and direct access to symmetrical/unsymmetrical 3,4-diarylmaleimides and pyrrolin-2-ones

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• 作者：Pal ; Manojit ; Swamy ; Nalivela Kumara ; Hameed ; P. Shahul ; Padakanti ; Srinivas ; Yeleswarapu ; Koteswar Rao
• 关键词：3 ; 4-Diarylmaleimide and pyrrolin-2-one ; Oxidative cyclization ; Phenacyl amide ; Oxygen
• 刊名：Tetrahedron
• 出版年：2004
• 出版时间：April 26, 2004
• 年：2004
• 卷：60
• 期：18
• 页码：3987-3997
• 全文大小：281 K

文摘

1,8-Diazabicyclo[5.4.0]undec-7ene (DBU) facilitated the oxidative cyclization of phenacyl amide in the presence of atmospheric oxygen under environmentally friendly conditions. The reaction has been studied under various conditions and a plausible mechanism is proposed. This ‘green’ reaction proceeds via intramolecular ring closure of the amide followed by subsequent reaction with molecular oxygen where DBU played a crucial role. A variety of phenacyl amides were treated with DBU in acetonitrile under an oxygen atmosphere to give the symmetrical/unsymmetrical 3,4-diarylsubstituted maleimides in good yields. Corresponding pyrrolin-2-ones however, were obtained in good to excellent yields when K₂CO₃ was used in place of DBU affording a practical synthesis of these compounds of potential biological interest.