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PREPARATION OF ESSENTIALLY ISOMERICALLY PURE METHYL E-2-(2-ARYLOXYMETHYLENE-PHENYL) CROTONATES, AND INTERMEDIATES THEREFOR
PREPARATION OF ESSENTIALLY ISOMERICALLY PURE METHYL E-2-(2-ARYLOXYMETHYLENE-PHENYL) CROTONATES, AND INTERMEDIATES THEREFOR
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机译:基本等纯的E-2-(2-芳氧基亚甲基-苯基)巴豆酸酯的制备及其中间体
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摘要
A process for preparing substantially isomer-pure E-2-(2-aryloxymethylenephenyl)-crotonic acid methyl esters having formula (Ia), in which R stands foran aromatic residue substitued by the usual groups and R' stands for a C1-C3alkyl group, is characterised in that a corresponding 2-(2-aryloxymethylenephenyl)-.alpha.-keto-acetic acid methyl ester having formula (II) with analkyl metal compound having formula (III), in which M stands for a metal ionequivalent, first yields the corresponding 2-(2-aryloxymethylene phenyl)-.alpha.-hydroxybutyric acid methyl ester having formula (IV), which is thendehydrated in the presence of an acid into a mixture of E- et Z-2-(2-aryloxymethylene phenyl)-crotonic acid methyl esters having formulas (Ia) and(Ib). This mixture is finally converted into the substantially isomer-pure E-2-(2-aryloxymethylene phenyl)-crotonic acid methyl ester (Ia) in the presence ofa base in an inert polar solvent.
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机译:一种制备基本上为异构体的纯E-2-(2-芳氧基亚甲基)的方法具有式(Ia)的苯基)-巴豆酸甲酯,其中R代表芳族残基被通常的基团取代,R'表示C1-C3烷基,其特征在于相应的2-(2-芳氧基亚甲基具有式(II)的苯基)-α-酮基乙酸甲酯与具有式(III)的烷基金属化合物,其中M代表金属离子当量,首先产生相应的2-(2-芳氧基亚甲基苯基)-具有式(IV)的α-羟基丁酸甲酯,然后将其在酸存在下脱水成E- et Z-2-(2-具有式(Ia)和式(Ia)的芳氧基亚甲基苯基)-巴豆酸甲酯(Ib)。最终将该混合物转化为基本上异构体纯的E-2-(2-芳氧基亚甲基苯基)-巴豆酸甲酯(Ia)在惰性极性溶剂中的碱。
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