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Preparation and structure determination of 1‐benzyl‐, 1‐methyl‐ and 1 H ‐5‐[(2‐nitro‐2‐phenyl)ethenyl]imidazoles
Author(s) -
Aulaskari Paula,
Ahlgrén Markku,
Rouvinen Juha,
Vainiotalo Pirjo,
Pohjala Esko,
Vepsäläinen Jouko
Publication year - 1996
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570330456
Subject(s) - chemistry , nitro , medicinal chemistry , knoevenagel condensation , organic chemistry , catalysis , alkyl
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 a ratio of 4:3 from the E ‐form with UV irradiation. The E ‐forms were more stable and the Z‐isomers changed again to the E ‐isomers in several weeks.