A new process that could directly prepare α-haloacetal of ketones from various ketones with N-halosuccinimide (NBS/NCS) and ethylene glycol in one step without any other catalysts was reported. The effects of solvents, NBS/NCS and reaction temperature were investigated. Under the optimal condition, most of α-haloacetals of ketones were obtained in 90–100% yield.
One-pot synthesis of <font>α</font>-bromoacetals of ketones from secondary alcohols and 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) in ethylene glycol
作者:Bingbing Han、Zubiao Zheng、Fang Wu、Aidong Wang
DOI:10.1080/00397911.2017.1378681
日期:2017.12.17
of ketones were prepared from various secondary alcohols with 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) and ethylene glycol through oxidation, bromination, and acetalization in one pot without the use of other catalysts under mild conditions. The effects of DBDMH, the solvent, and N-bromosuccinimide on the reaction were investigated. Under the optimal conditions, most α-bromoacetals of ketones were
[EN] PROCESS FOR PRODUCING TRIFLUOROMETHYL-SUBSTITUTED 2-ALKOXYACETOPHENONE DERIVATIVES<br/>[FR] PROCEDE DE PRODUCTION DE DERIVES DE 2-ALCOXYACETOPHENONE TRIFLUOROMETHYLE-SUBSTITUEE
申请人:CENTRAL GLASS CO LTD
公开号:WO2004014887A1
公开(公告)日:2004-02-19
A process for producing a brominated acetal (represented by the formula 3) includes (a) brominating a trifluoromethyl-substituted acetophenone by Br2 in the presence of an alkylene diol. It is optional to produce a trifluoromethyl-substituted 2-alkoxyacetophenone derivative (represented by the formula 9) by (b) reacting the brominated acetal with a metal alkoxide, thereby converting the brominated acetal into an ether; and (c) hydrolyzing the ether in the presence of an acid catalyst to remove an acetal group from the ether, thereby producing the 2-alkoxyacetophenone derivative. Alternatively, the 2-alkoxyacetophenone can be produced by (a) reacting a trifluoromethyl-substituted phenacyl halide with an acetalization agent, thereby converting the phenacyl halide into an acetal; (b) reacting the acetal with a metal alkoxide, thereby converting the acetal into an ether; and (c) hydrolyzing the ether in the presence of an acid catalyst to remove the acetal group from the ether.