4 results about "Formic acid ethyl ester" patented technology

This invention discloses a method for preparing ethyl 4-pyrazolamide. A dichloromethane solution of ethyl 3-(N,N-dimethylamino)acrylate is added dropwise to a dichloromethane solution containing a chlorine-containing reagent and N,N-dimethylformamide. After addition, the mixture is stirred until the reaction is complete, yielding a reaction solution. The reaction solution is then directly added dropwise to an alcoholic solution of hydrazine hydrate, and the resulting reaction yields ethyl 4-pyrazolamide. This method uses readily available raw materials, has mild reaction conditions, high yield, and is easily industrialized.

The application discloses a preparation method of relugolix and belongs to the field of drug synthesis. The method uses 2-[(2,6-difluorobenzyl) n-propoxy amido]-4-(dimethylamino) methyl-5-(4-nitrophenyl) thiophene-3-carboxylic acid ethyl ester (formula II) as a starting material, and relugolix is prepared through the following steps: inorganic base hydrolysis, amide condensation, inorganic base cyclization, 10% Pd / C catalytic hydrogenation, and finally amide condensation with methoxyamino carbonic acid phenyl ester. The starting material used in the preparation method is cheap and easy to obtain, the reaction is mild, the operation is simple, the product has high purity and high yield, no biuret by-product is detected, and the method is suitable for industrial production.

A preparation method of 3-iodo-1H-indole-2-carboxylic acid, which comprises the following steps: taking indole-2-carboxylic acid ethyl ester as raw material, converting into 3-formyl-1H-indole-2-carboxylic acid ethyl ester, then converting into 3-iodo-1H-indole-2-carboxylic acid ethyl ester, and finally converting into the target compound 3-iodo-1H-indole-2-carboxylic acid through an ester hydrolysis reaction. The synthesis method realizes the conversion from 3-formyl-1H-indole-2-carboxylic acid ethyl ester to 3-iodo-1H-indole-2-carboxylic acid ethyl ester in a simple method in a key step; finally, the compound 3-iodo-1H-indole-2-carboxylic acid is prepared through simple operation, low cost and relatively mild reaction conditions.

The application discloses a preparation method of a monoamine oxidase B inhibitor, and comprises the following steps: 6-fluoroindole and 1-(dimethylamino)-2-nitroethylene are subjected to trifluoroacetic acid catalysis to generate 6-fluoro-3-[(E)-2-nitrovinyl]-1H-indole, and then subjected to sodium borohydride and iron powder / hydrochloric acid reduction to generate 6-fluoro-tryptamine; under an acidic condition, Pictet-Spengler reaction is carried out between 6-fluoro-tryptamine and ethyl glyoxylate to generate ethyl 7-fluoro-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-1-carboxylate and 7-fluoro-4,9-dihydro-3H-pyrido[3,4-b]indole-1-carboxylate, and then subjected to oxidative dehydrogenation aromatization reaction to generate ethyl 7-fluoro-9H-pyrido[3,4-b]indole-1-carboxylate; under the catalysis of aluminum trichloride, amine ester exchange reaction is carried out between ethyl 7-fluoro-9H-pyrido[3,4-b]indole-1-carboxylate and 3-fluorobenzylamine to generate a target compound. The method has high overall yield.