申请人:Roche Vitamins Inc.
公开号:US05786518A1
公开(公告)日:1998-07-28
A novel process for the manufacture of a .gamma.-halotiglic aldehyde HalH.sub.2 C--CH.dbd.C(CH.sub.3)--CHO \x9bI!, wherein Hal signifies chlorine or bromine, comprises haloalkoxylating a 1-alkoxy-2-methyl-1,3-butadiene H.sub.2 C.dbd.CH--C(CH.sub.3).dbd.CH--OR.sup.1 \x9bII!, wherein R.sup.1 signifies C.sub.1-4 -alkyl, using a particular halogenating agent in a C.sub.1-4 -alkanol (R.sup.2 OH) and hydrolyzing the thus-obtained .gamma.-halotiglic aldehyde dialkyl acetal HalH.sub.2 C--CH.dbd.C(CH.sub.3)--CH(OR.sup.1)(OR.sup.2) \x9bIII! to the desired .gamma.-chloro- or .gamma.-bromotiglic aldehyde I. The halogenating agent used in this process is selected from an alkali metal hypochlorite, an alkali metal hypobromite, an alkaline earth metal hypochlorite, an alkaline earth metal hypobromite, tert.butyl hypochlorite, N-bromoacetamide, 1.3-dichloro-5,5-dimethylhydantoin and 1,3-dibromo-5,5-dimethylhydantoin. Further aspects of the present invention are the use of the thus-manufactured .gamma.-halotiglic aldehyde for the production of .gamma.-acetoxy-tiglic aldehyde or of a Wittig aldehyde halide Hal-Ph.sub.3 P.sup.+ CH.sub.2 --CH.dbd.C(CH.sub.3)--CHO \x9bVII!, wherein Hal signifies chlorine or bromine and Ph signifies phenyl, as well as a process for the catalytic dealkoxylation of the 1,1,3-trialkoxy-2-methyl-butane CH.sub.3 --CH(OR.sup.1)--CH(CH.sub.3)--CH(OR.sup.1).sub.2 \x9bVI! to the corresponding 1-alkoxy-2-methyl-1,3-butadiene II in the gas phase using an aluminium silicate of medium specific surface as the catalyst. The products I, .gamma.-acetoxy-tiglic aldehyde and VII are known, important intermediates for the production of various apocarotenoids and diapocarotenoids as well as of Vitamin A.
一种用于制造γ-卤代硫代乙醛HalH.sub.2 C--CH.dbd.C(CH.sub.3)--CHO的新工艺,其中Hal表示氯或溴,包括在C.sub.1-4-烷醇(R.sup.2 OH)中使用特定卤代氧烷化剂将1-烷氧基-2-甲基-1,3-丁二烯H.sub.2 C.dbd.CH--C(CH.sub.3).dbd.CH--OR.sup.1转化为γ-卤代硫代乙醛HalH.sub.2 C--CH.dbd.C(CH.sub.3)--CH(OR.sup.1)(OR.sup.2),然后水解得到所需的γ-氯代或γ-溴代硫代乙醛I。该工艺中使用的卤代氧烷化剂选自碱金属次氯酸盐、碱金属次溴酸盐、碱土金属次氯酸盐、碱土金属次溴酸盐、叔丁基次氯酸盐、N-溴乙酰胺、1,3-二氯-5,5-二甲基海因酮和1,3-二溴-5,5-二甲基海因酮。本发明的另一方面是利用所制备的γ-卤代硫代乙醛用于生产γ-乙酰氧基硫代乙醛或Wittig硫代乙醛卤代物Hal-Ph.sub.3 P.sup.+ CH.sub.2--CH.dbd.C(CH.sub.3)--CHO,其中Hal表示氯或溴,Ph表示苯基,以及一种用于在气相中使用中等比表面积的硅酸铝作为催化剂对1,1,3-三烷氧基-2-甲基丁烷CH.sub.3--CH(OR.sup.1)--CH(CH.sub.3)--CH(OR.sup.1).sub.2进行催化脱烷氧化的工艺,将其转化为相应的1-烷氧基-2-甲基-1,3-丁二烯II。产品I、γ-乙酰氧基硫代乙醛和VII是已知的,用于生产各种类胡萝卜素和二类胡萝卜素以及维生素A的重要中间体。