Simple and efficient methods for selective preparation of α-mono or α,α-dichloro ketones and β-ketoesters by using DCDMH
作者:Zizhan Chen、Bin Zhou、Huihua Cai、Wei Zhu、Xinzhuo Zou
DOI:10.1039/b815169e
日期:——
New processes that can selectively prepare α-mono or α,α-dichloro ketones and β-ketoesters using 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) are reported. Using silica gel as the catalyst and methanol as the solvent and heating for 1 h under reflux, α-monochlorinated products were selectively obtained in 86–98% yield. However using a deep eutectic solvent (choline chloride: p-TsOH = 1:1) as the solvent
One-Step Conversion of Acetophenones to <font>α</font>-Haloacetophenone Dimethyl Acetals Using DCDMH/DBDMH and Molecular Sieve in Methanol
作者:Bin Zhou、Zizhan Chen、Zubiao Zheng、Bingbing Han、Xinzhuo Zou
DOI:10.1080/00397911.2010.540696
日期:2012.5.15
Using DCDMH/DBDMH as N-halo reagent, piperidine as catalyst, and 4-A molecular sieve as water-removing agent, alpha-haloacetophenone dimethyl acetals were directly obtained from the solvent of methanol. As to the substrates with electron-withdrawing groups, the conversions were 80-100%.