Method for preparing optically active 5-methyl-2-(1-methyl-butyl)-5-propyl-1,3-dioxan
申请人:Cognis Deutschland GmbH
公开号:US06297390B1
公开(公告)日:2001-10-02
The present invention relates to a method for preparing optically active 5-methtyl-2-(1-methtyl-butyl)-5-propyl-1,3-dioxan, wherein said method comprises the following steps: converting lactic acid methylic ester into the corresponding N,N-disubstituted amid (aminolysis with piperidine and/or pyrrolidine); protecting its free OH function by a reaction with ethylvinylether in the presence of p-pyridiniumtosylate as a catalyst; submitting the N-pentamethylen- or N-tetramethylenlactamide thus obtained to a Grignard reaction in a conventional way so as to produce the corresponding &agr;, &bgr;-unsaturated ketone; further separating in a conventional way (e.g. agitation with acetic acid) the protection group introduced during the second step; acetalating in a conventional way the ketone function (e.g. by reaction with 2-methyl-2-propyl-1,3-propanediol); mesylating the free OH function by reaction with methansulfonic acid chloride in pyridine; submitting the intermediate thus obtained to a reducing 1,2-transposition in the presence of trimethylammonium and diisobutylaluminum hydride while maintaining the sterochemistry; and converting by catalytic hydrogenation the dehydro compound thus abtained into optically active 5-methyl-2-(1-methyl-butyl)-5-propyl-1,3-dioxan. The optically active 5-methyl-2-(1-methyl-butyl)-5-propyl-1,3-dioxan of the present invention exhibits a remarkable scent profile as well as a high scent intensity and may be used as perfume.
本发明涉及一种制备光学活性5-甲基-2-(1-甲基丁基)-5-丙基-1,3-二噁烷的方法,其包括以下步骤:将乳酸甲酯转化为相应的N,N-二取代酰胺(通过与哌啶和/或吡咯啉的胺解反应);在p-吡啶基对甲苯磺酸盐存在下,通过与乙基乙烯醚反应保护其自由OH功能;将所得的N-戊亚甲基或N-四亚甲基乳内酰胺以传统方式进行格氏反应,以产生相应的α,β-不饱和酮;在传统方式下进一步分离(例如通过乙酸的搅拌)第二步引入的保护基;通过与2-甲基-2-丙基-1,3-丙二醇反应,在传统方式下醛基化(例如乙酸的搅拌);通过在吡啶中与甲硫酸氯反应,甲磺酰化自由OH功能;在保持立体化学的同时,通过在三甲基铵和二异丁基铝氢化物存在下进行还原1,2-转位反应;通过催化氢化将所得的脱氢化合物转化为光学活性5-甲基-2-(1-甲基丁基)-5-丙基-1,3-二噁烷。本发明的光学活性5-甲基-2-(1-甲基丁基)-5-丙基-1,3-二噁烷呈现出显著的气味特征以及高气味强度,可用作香水。