- A (S)- methyl multi-Pakistan method for the preparation of intermediate compounds
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The invention discloses a preparation method for a (S)-methyldopa intermediate compound shown as formula (II). The method comprises the steps of: in the presence of inorganic acid, subjecting the compound shown as formula (I) and (2S, 3S)-tartaric acid to salt forming reaction as shown below in water, with the mole ratio of the (2S, 3S)-tartaric acid to the compound shown as formula (I) being 0.5:1-0.6:1. The preparation method provided by the invention employs (2S, 3S)-tartaric acid as the resolving agent, which has the characteristics of high-usage, high optical purity, simple operation and low cost. (salt forming reaction).
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- L - 3 - (3, 4 - dimethoxyphenyl) -2 - amino -2 - methyl propionitrile hydrochloride preparation method
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The invention relates to the technical field of medical chemistry and aims at providing a method for preparing L-3-(3,4-dimethoxyphenyl)-2-amino-2-methyl propionitrile hydrochloride. The method comprises the following steps: adding veratone, sodium cyanide, ammonium chloride and ammonia water into a reaction kettle, and introducing ammonia gas; cooling and performing centrifugal separation after the reaction is ended, thereby obtaining D,L-aminopropionitrile; dissolving the D,L-aminopropionitrile in an organic solvent, adding L(+)-2,3-dihydrobutanedioic acid, stirring and reacting; adding hydrochloric acid for stirring, and cooling for performing centrifugal separation treatment, thereby obtaining the L-3-(3,4-dimethoxyphenyl)-2-amino-2-methyl propionitrile hydrochloride. According to the method disclosed by the invention, the conversion rate of veratone is high and can be 90-95 percent. The ammonia water mother solution and organic solvent produced in the reaction can be recycled and are repeatedly used for many times, and the environmental pollution is reduced. The solvent used in the reaction replaces water, and sewage emission is completely reduced. The amount of a resolving agent can be reduced by a half, and the resolving effect is good; complex operations such as regulation of the pH value and the like are not needed, and the preparation process is stable and easy to operate.
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Paragraph 0024; 0028-0030; 0032; 0036-0038; 0040; 0044-0046
(2017/06/02)
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