First Vilsmeier-Haack Synthesis of Flavones using<i>bis</i>-(Trichloromethyl) Carbonate/Dimethylformamide
作者:W. K. Su、X. Y. Zhu、Z. H. Li
DOI:10.1080/00304940802710947
日期:2009.3.20
cyclodehydration of 1-(2-hydroxyphenyl)-3-aryl-1,3-propanediones. Many of these procedures use strong acids such as H2SO4, 5-6 HCl, 7 HBr or HI, 8 catalysts such as NaHSO4/SiO2, 9 H3PMo12O40·nH2O/SiO2, 10 H3PW12O40·nH2O/SiO2, 10 non-aqueous cation-exchange resin, 11 or supported trifluoromethanesulfonicacid. 12 All of these agents require high temperatures to complete the reaction. Other methods include
A new protocol for total synthesis of natural product frutinone A was accomplished in three steps by using inexpensive 2′-hydroxyacetophenone as starting material. The key intermediate 3-(2-chlorobenzoyl)-4-hydroxycoumarin was synthesized in one pot through Baker–Venkataraman rearrangement of 2-acetylphenyl 2-chlorobenzoate followed by introduction of methyl chloroformate under basic conditions. Then
A facile synthesis of flavones catalysed by gallium(III) triflate
作者:Can Jin、Fei He、Huayue Wu、Jiuxi Chen、Weike Su
DOI:10.3184/030823409x396409
日期:2009.1
Ga(OTf)3 was explored as a novel catalyst for the cyclisation of 1-(2-hydroxyphenyl)-3-aryl-1,3-propanediones in nitromethane to flavones with excellent yields.