79results about How to "Reduce difficulty of reaction" patented technology

The invention mainly relates to a synthesis method of alvimopan. A preparation method of the related alvimopan comprises the following steps of: condensing phenylpropionic acid and substituted oxazolidone; undergoing reaction with chloromethyl benzyl ether under the action of a catalyst to obtain a single configuration; hydrolyzing, and recycling oxazolidone to obtain carboxylic acid; condensing with glycinate; performing deprotection and undergoing reaction with a leaving group donor; butting with (+)-(3R,4R)-4-(3-hydroxy phenyl)-3,4-dimethyl piperidine to obtain alvimopan ester; and hydrolyzing to obtain the alvimopan. The invention also relates to a novel intermediate of the alvimopan and preparation methods of the alvimopan and the novel intermediate of the alvimopan. The technical scheme of the invention has the advantages of simple process, low cost and high product purity, and is suitable for industrial production.

The invention relates to a preparation method of a cholesterol reduction drug, particularly relates to a preparation method of pitavastatin calcium as a crude drug of the cholesterol reduction drug, and aims at the problems that the pitavastatin calcium synthetic technology in the prior art is long in steps and complicated in operation, and uses strongly corrosive reagents which is environmentally unfriendly, causes serious corrosion to equipment, and may not facilitate industrial production. The invention provides the new preparation method of the pitavastatin calcium, the new preparation method is as follows: 3-bromomethyl-2-cyclopropyl-4-(4-fluorophenyl)quinoline is prepared from 2-cyclopropyl-4-(4-fluorophenyl)-3-quinolinecarboxaldehyde by a one step reaction, and then reacts with an organophosphorus reagent to obtain pitavastatin calcium intermediate phosphorus ylide, on the basis of improving of the yield to 80%, the reaction steps are reduced, and the reaction difficulty is reduced, and hydroxylamine hydrochloride is selected as a deprotection reagent, so that the new preparation method is mild in reaction conditions, environmentally friendly, high in yield, and beneficial to industrial production.

The invention relates to a process of ammonium sulfite method caramel color with color index being more than or equal to 250000EBC. The process successively comprises the following steps: raw material metering and concentrating, a first time catalyst adding: adding 10 percent to 30 percent sulfite and 5 percent to 15 percent ammonium substances or ammonia substances or amine substances in the concentrated raw material, a first time of pressurized reaction, a second time catalyst adding: adding 0.01 percent to 0.05 percent metallocene catalyst into a material after the ending of the first time of reaction, a second time of pressurized reaction, blending, and metering and filling. According to the process, the ammonium sulfite method caramel color process is first used, after a reaction system generates a lot of heterocyclic rings and olefins, the metallocene catalyst is added to perform the second time of pressurized reaction, transition metal with positive valence in the metallocene catalyst is combined with electron of a monomer molecular to realize stereospecific coordination polymerization, esterification is avoided, reaction difficulty is decreased, carbon chain growth and conjugated double bond increase are performed, so as to obtain the caramel color with the color index being more than or equal to 250000EBC, and the caramel color is good in fluidity.