Silica gel catalyzed conversion of dimethyl 2-(5-bromo-2-hydroxyphenyl)-3-(triphenylphosphoranylidene)butanedioate to methyl 6-bromo-2-oxo-2H-chromene-4-carboxylate in solvent-free conditions

被引:46
作者
Ramazani, A [1 ]
Souldozi, A [1 ]
机构
[1] Zanjan Univ, Dept Chem, Zanjan, Iran
关键词
4-bromophenol; chromene; dimethyl acetylenedicarboxylate; silica gel; vinyltriphenylphosphonium salt;
D O I
10.1080/714040980
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate, by 4-bromophenol leads to vinyltriphenylphosphonium salt, which undergoes aromatic electrophilic substitution reaction with conjugate base to produce dimethyl 2-(5-bromo-2-hydroxyphenyl)3-(triphenylphosphoranylidene)butanedioate. Silica gel was found to catalyze conversion of dimethyl 2-(5-bromo-2-hydroxyphenyl)-3-(triphenylphosphoranylidene)butanedioate to methyl 6-bromo-2-oxo-2H-chromene-4-carboxylate in solvent-free conditions at 80degreesC in fairly high yield.
引用
收藏
页码:2663 / 2666
页数:4
相关论文
共 13 条