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Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines
Published on: June 23, 2019
Microwave-assisted four-component, one-pot condensation reaction: an efficient synthesis of annulated pyridines
Chao-Guo Yan1, Xi-Mei Cai, Qi-Fang Wang
1College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China. cgyan@yzu.edu.cn
Abstract:
A one-pot, effective synthesis of pyridines by a modified Kröhnke procedure is described. Polysubstituted annulated pyridines were synthesized in high yields by four-component, one-pot cyclocondensation reactions of N-phenacylpyridinium bromide, aromatic aldehydes, acetophenones or cyclic ketones in the presence of ammonium acetate and acetic acid, assisted by microwave irradiation. In this procedure, cyclic ketones with two alpha-CH(2) groups yield annulated pyridines with additional alpha-benzylidene groups, which are derived in situ from double aldol condensation of cyclic ketones with two moles of aromatic aldehydes.
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