Furan Derivatives 90. A New Nucleophilic Substitution in Furan Series
作者:
R. Kada,
V. Knoppová,
J. Kováč,
期刊:
Synthetic Communications
(Taylor Available online 1977)
卷期:
Volume 7,
issue 2
页码: 157-160
ISSN:0039-7911
年代: 1977
DOI:10.1080/00397917708050728
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The Knoevenagel condensation of 5-arylthio-, 5-heteroarlthio- and 5-arylsulphonyl-2-furaldehydes, respectively, with malonitrile in ethanol in the presence of basic catalysts (sodium ethoxide) gives rise to corresponding α, β-unsaturated compounds1. Now, we have found a different course of the condensation, when saturated heterocyclic secondary amines (piperidine, morpholine, pyrolidine and N-methylpiperazine) as catalysts were used. In the first step of this reaction the normal condensation product i.e. 2-cyano-3-(5-arylthio-2-furyl)-, 2-cyano-3-(5-heteroarylthio-2-furyl)- and 2-cyano-3-(5-arylsulphonyl-2-furyl) acrylonitrile is formed which further reacts according to the SNmechanism with the present secondary amine to the appropriate 5-aminoderivative. In order to increase the yields of reaction products, the condensation was carried out with equimolar amounts of aldehyde, malonitrile and secondary amine in absolute ethanol at room temperature (Reaction 1).
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