Preparation and structure determination of 1-benzyl-, 1-methyl- and 1<i>H</i>-5-[(2-nitro-2-phenyl)ethenyl]imidazoles
作者:Paula Aulaskari、Markku Ahlgrén、Juha Rouvinen、Pirjo Vainiotalo、Esko Pohjala、Jouko Vepsäläinen
DOI:10.1002/jhet.5570330456
日期:1996.7
1-R-5-[(2-Nitro-2-phenyl)ethenyl]imidazoles (R = Bn, Me, H) 6a,b,c were synthesized by the Knoevenagel reaction of the corresponding aldehydes 4a,b,c with phenylnitromethane 5. The E-isomers 6a,b,c were precipitated from the reaction mixture as crystalline compounds in 89, 81 and 60% yields, respectively. Traces of the Z-isomers 6a′b′,c′ were found in the reaction mixtures but could be obtained in
1- R -5-[(2-硝基-2-苯基)乙烯基]咪唑(R = Bn,Me,H)6a,b,c通过相应的醛4a,b,c与苯基硝基甲烷的Knoevenagel反应合成5。所述ë异构体6A,B,C被从反应混合物中以结晶化合物在89,81和60%的产率分别沉淀。在反应混合物中发现了痕量的Z-异构体6a'b',c',但是可以通过紫外线照射从E-型中以4:3的比例获得。该Ë -forms更加稳定和Z异构体又变到é异构体在几个星期。