Microwave-assisted four-component, one-pot condensation reaction: an efficient synthesis of annulated pyridines.
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.
Yan
Chao-Guo
CG
College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China. cgyan@yzu.edu.cn
Cai
Xi-Mei
XM
Wang
Qi-Fang
QF
Wang
Ting-Yu
TY
Zheng
Ming
M
D018360:Crystallography, X-Ray; D008872:Microwaves; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry
D011725:Pyridines