33 results about "Ethylmalonic acid" patented technology

A process for preparation of diethyl 2-aetamido-2-(4-octyl phenyl)ethyl malonate (III), a key intermediate of fingolimod hydrochloride comprising reaction of 2-(4-octylphenyl)ethyl iodide (IV) with diethyl acetamido malonate in presence of a base and an iodinating agent and in an organic solvent. The compound of formula (III) thus obtained provided fingolimod hydrochloride (Ia) having associated impurities below the regulatory limits.

The invention discloses a method for preparing high-quality mercaptoacetic acid from a tail solution from O-alkyl-N-alkyl thinocarbamate production. The method comprises the following steps: (1) performing acidizing treatment on the tail solution by using an inorganic acid, and controlling the pH value to be 0.5-1.5; (2) leaving to stand for 6-48 hours, separating suspended organic matters, extracting by using an organic solvent, and extracting by using an extraction agent, thereby obtaining an extraction liquid, wherein the volume ratio of the total amount of the organic solvent to an acidifying liquid is (2.5:0.01)-(2.5:0.1), the organic solvent consists of 40-60wt% of glutaric acid diethyl ester and 40-060wt% of ethyl malonic acid diethyl ester, the volume ratio of the total amount of the extracting agent to a new acidifying liquid is (2:0.1)-(2:2), and the extracting agent is prepared by mixing n-amyl ether, isoamyl ether and sec-butyl methyl ether in a mass ratio of (1-3):(1-3):(1-3); (3) removing the solvent and water from the extraction liquid, thereby obtaining crude acid; (4) performing flash evaporation on the crude acid. The method is high in recycling rate, high in product purity, good in quality and simple in process.