METHOD OF MANUFACTURING 1-CHLORO-2-METHYL-4-ACYLOXY-2-BUTENE DERIVATIVES
申请人:SHEN Runpu
公开号:US20070270607A1
公开(公告)日:2007-11-22
1-Chloro-2-methyl-4-acyloxy-2-butene derivatives can be synthesized in good yields and high purity starting from isoprene and employing a chlorohydrin formation reaction in a system made of N-chloroisocyanuric acid derivatives and water, followed by esterification and rearrangement of the crude product mixture.
P(CH<sub>3</sub>NCH<sub>2</sub>CH<sub>2</sub>)<sub>3</sub>N as a Dehydrobromination Reagent: Synthesis of Vitamin A Derivatives Revisited
作者:Andrzej E. Wróblewski、John G. Verkade
DOI:10.1021/jo010648+
日期:2002.1.1
Although P(CH(3)NCH(2)CH(2))(3)N (1) was found to be less effective than 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in the removal of hydrogen bromide from vitamin A intermediates 13-cis-10-bromo-9,10-dihydroretinyl acetates (6) and 14-bromo-9,14-dihydroretinyl acetate (11) when the reaction was carried out in refluxing benzene, in acetonitrile at room temperature
Stereocontrolledconvergentsynthesis of vitamin A was achieved by the doubleelimination method employing the C10 sulfone and the C10 aldehydes as starting materials. Thus the all-trans and 13-cis isomers were obtained with the stereochemical purity of 95% and 90%, respectively.