1-methylamino-1- methylthio-2-nitroethylene synthesis method

Abstract

The invention discloses a new chemical synthesizing method of 1-motol-1-methylmercapto-2-nitroethylene as one intermediate of ulcer drug ranitidine, which comprises the following steps: adopting nitromethane, carbon bisulphide and potassium hydroxide as initial reacting material; synthesizing 1, 1-dimethyldisulphide-2-nitro ethylene to dissolve in the water; reacting with aminomethane to synthesize new intermediate product; filtering to obtain the product.

Description

technical field [0001] The invention relates to the field of chemical industry and pharmacy, in particular to a new chemical synthesis method of 1-methylamino-1-methylthio-2-nitroethylene, one of the intermediates for synthesizing peptic ulcer drug ranitidine. Background technique [0002] 1-methylamino-1-methylthio-2-nitroethylene is an important intermediate in the preparation of peptic ulcer drug ranitidine, and its production directly affects the quality and cost of ranitidine. For the synthesis of N-methyl-1-methylthio-2-nitroethyleneamine, there are many reports in the literature, but the common shortcomings of these methods are: there are many by-products and the yield is too low; because a large amount of The safety of the production process using flammable and explosive chemical solvents is poor; the process route is long and the operation is complicated. Several routes reported in the literature are described as follows: [0003] (1) Chemical solvent method [Chen...

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Problems solved by technology

For the synthesis of N-methyl-1-methylthio-2-nitroethyleneamine, there are many reports in the literature, but the common shortcomings of these methods are: there are many by-products and the yield is too low; because a large amount of The use of flammable and explosive chemical solvents has poor safety in the production process; the process route is long and the operation is complicated

[0005] The main disadvantage of this route is: (a) the reaction process needs to be carried out in organic solvent methanol, ethanol, DMF, and the discharge of chemical solvents causes environmental pollution; (b) methanol, ethanol are dangerous chemicals, flammable and explosive, and the production process poor security

(c) The intermediate product 1,1-dimethylthio-2-nitroethylene is insoluble in water and needs to be reacted in a polar aprotic organic solvent such as DMF. After the reaction is completed, the recovery cost of the solvent DMF is high

(d) When 1,1-dimethylthio-2-nitroethylene is reacted with monomethylamine to prepare 1-methylamino-1-methylthio-2-nitroethylene, a side reaction is likely to occur to generate 1,1 -Dimethylamino-2-nitroethylene, resulting in difficulties in the purification of the product 1-methylamino-1-methylthio-2-nitroethylene, and a decline in product quality

(e) The reaction yield is low, less than 40%

[0009] The main disadvantages of this process route are: low yield (about 36%); harsh and complicated operating conditions; the process uses carcinogenic chemical solvent benzene; catalyst tetrabutylammonium bromide and rare earth modified zeolite are expensive and costly; The process cycle is long, not suitable for industrial production

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