33results about How to "Less impurities in the reaction" patented technology

The present invention adopts the Reppe synthesis method to prepare strawberry acid. First, piperylene, carbon monoxide and water are used as raw materials, and noble metal rhodium salt and organic phosphine ligand are used as catalysts to obtain the cis-trans iso-iso of 2-methyl-3-pentenoic acid. The intermediate product is then isomerized to generate trans-2-methyl-2-pentenoic acid, i.e. trans-strawberry acid.

The invention relates to a synthesis method of neotame. The method comprises the following steps: (1) adding aspartame and 3,3-dimethyl-butyl aldehyde to an organic solvent in a vacuum state, reacting at the reaction temperature of 20-50 DEG C for 5-24 hours, carrying out concentration and separation at 0-50 DEG C after reaction is ended, concentrating to obtain white paste, adding deionized water to devitrify, thus obtaining a neotame intermediate imine in a centrifuging manner; (2) adding imine and an organic solvent to a hydrogenation reactor, introducing hydrogen until the pressure is 0.1-0.5MPa, adding a catalyst, reacting at the temperature of 35-40 DEG C for 5-30 hours, filtering and removing the catalyst, concentrating the filtrate and removing an organic solvent, and recrystallizing and purifying by water, methanol or ethanol, so as to obtain the neotame. According to the synthesis method, the defects in the prior art are overcome, high-purity imine is generated, the activity of the catalyst is reduced, the selectivity of the catalyst on the imine is increased, the service life of the catalyst is prolonged, the reaction impurity is reduced, and the product purity is improved.

The invention belongs to the technical field of medicines, and particularly relates to a preparation method of N(2)-L-alanyl-L-glutamine. The preparation method of the N(2)-L-alanyl-L-glutamine comprises the following steps of (1) preparing L-phthaloyl-alanyl chloride; (2) preparing phthaloyl-L-alanyl-L-glutamic acid; (3) preparing phthaloyl-L-alanyl-L-glutamic acid anhydride; (4) preparing phthaloyl-L-alanyl-L-glutamine; (5) preparing an N(2)-L-alanyl-L-glutamine crude product; (6) preparing an N(2)-L-alanyl-L-glutamine refined product. The product obtained through the final deprotection process of the preparation method as a pilot plant test or a production scale process route is higher in purity; the liquid-phase purity of the product is higher than 99.9% through primary purification, and the product is low in impurity content.

The invention discloses a method for dehalogenating the 9-position of a steroid hormone compound. The method comprises: dissolving a 9-halogenated-11-hydroxy steroid compound or a 9-halogenated-11-hydroxy ester steroid compound in an organic In the solvent, after heating up to a certain temperature, slowly add an appropriate amount of dehalogenation reagent, and detect after a period of reaction. After the reaction is complete, concentrate under reduced pressure to remove part of the solvent, cool down to crystallize or add water to crystallize, precipitate a solid, and filter to obtain the target product 11 ‑carbonyl steroids or 11‑hydroxyester steroids. The invention has simple operation, less reaction impurities, high yield, avoids the use of metal dehalogenating agent and mercapto fatty acid, reduces pollution of three wastes, and is suitable for industrial production.