Process for the preparation of methyl
(-)-(2R,3S)-2,3-epoxy-3-(4-methoxy-phenyl)propionate
    6.
    发明授权
    Process for the preparation of methyl (-)-(2R,3S)-2,3-epoxy-3-(4-methoxy-phenyl)propionate 失效
    制备( - ) - (2R,3S)-2,3-环氧-3-(4-甲氧基 - 苯基)丙酸甲酯的方法

    公开(公告)号:US5169779A

    公开(公告)日:1992-12-08

    申请号:US654518

    申请日:1991-02-13

    CPC分类号: C12P41/005 C12P17/02

    摘要: A process for the preparation of methyl (-)-(2R,3S)-2,3-epoxy-3-(4-methoxyphenyl)propionate, which comprises subjecting the dextrorotatory (2S,3R) enantiomer, present in a starting mixture containing both the levorotatory (2R,3S and dextrorotatory (2S,3R) enantiomers, to a transesterification reaction, in an anhydrous medium and in the presence of an enzyme which does not affect the levorotatory (2R,3S) enantiomer. The latter is an intermediate for the synthesis of compounds such as Diltiazem.

    摘要翻译: ( - ) - (2R,3S)-2,3-环氧-3-(4-甲氧基苯基)丙酸甲酯的制备方法,其包括使起始混合物中存在的右旋(2S,3R)对映异构体 在无水介质中和在不影响左旋(2R,3S)对映体的酶的存在下,将左旋(2R,3S和右旋(2S,3R))对映异构体转化成酯交换反应,后者是中间体 用于合成化合物如地尔硫卓。

    Preparation of diphenylazomethines
    7.
    发明授权
    Preparation of diphenylazomethines 失效
    二苯基偶氮甲碱的制备

    公开(公告)号:US4638080A

    公开(公告)日:1987-01-20

    申请号:US832690

    申请日:1986-02-25

    CPC分类号: C07C251/24 C07C249/02

    摘要: Process for preparing diphenylazomethines of formula (II) ##STR1## by decarboxylation of diphenylazomethines of formula (I) ##STR2## in which X.sub.1 and X.sub.2 each denote, independently of each other, a hydrogen atom or a halogen atom or a methyl radical,R.sub.1 is H or linear or branched (C.sub.1-4) alkyl radical,R.sub.2 is the radical COOH, a linear or branched (C.sub.1-4) alkyl radical, the radical CONH.sub.2 or a linear or branched COO(C.sub.1-4) alkyl radical, andR.sub.3 denotes a hydrogen atom or the methyl radical.

    摘要翻译: 通过使式(I)的二苯偶氮甲基化合物(I)脱羧制备式(II)的二苯基偶氮甲酰胺的方法其中X1和X2各自独立地表示氢原子或卤素原子 或甲基,R1为H或直链或支链(C1-4)烷基,R2为自由基COOH,直链或支链(C1-4)烷基,基团CONH2或直链或支链COO(C1- 4)烷基,R 3表示氢原子或甲基。