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 provides a method for grading biomass, preparing furfural and preparing levulinic acid (LA) through two steps. The method comprises the following steps: processing a biomass raw material by using an acid / organic solvent combination system to separate lignose, hemicellulose and cellulose, converting hemicellulose into xylooligosaccharide, and converting cellulose into amorphous cellulose; extracting xylooligosaccharide by water, and converting xylooligosaccharide into furfural; and carrying out two-step acid hydrolysis on amorphous cellulose-based residues to make amorphous cellulose in residues converted into 5-HMF (5-hydroxymethylfurfural), introducing the 5-HMF to a second reactor with acidic environment, and carrying out acid hydrolysis to generate the LA. The method has the advantages of extremely high recovery rate / yield of sugar, FF and LA, few side reactions, high recovery rate and small chemical structure change of lignin, less water consumption, fast reaction, low requirements on a reactor, recycling of all reagents, and environmental protection.

The invention provides sevelamer niacin, a preparation method and an application. The sevelamer has a structural formula I shown as follows; wherein in the structural formula I, the ratio of (a+b): c is 45: 1 to 2: 1, m represents an integer which is not the zero or negative number, each x independently represents 0 or 1, and each x can not be 0 at the same time; and the proportion of the sevelamer niacin is 2.00-2.50. The sevelamer niacin has similar therapeutic effect with sevelamer hydrochloride under the condition that the usage amount of sevelamer niacin is 50% of that of sevelamer hydrochloride.

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 discloses a preparation method of 7-amino-3-methoxymethyl-3-cephem-4-carboxylic acid, and relates to the technical field of preparation of pharmaceutical intermediates. The method includes the steps that under the protection of nitrogen, 7-aminocephalosporanic acid, a silane reagent and an imidazole catalyst are stirred for 0.5-2 h at 30-35 DEG C in a water-soluble organic solvent; then, the mixture is cooled to 0-5 DEG C, methanesulfonic acid, trimethyl borate and methyl alcohol are added, a methoxylation reaction is conducted with the temperature controlled to be 0-5 DEG C, and 7-amino-3-methoxymethyl-3-cephem-4-carboxylic acid is obtained, wherein the silane reagent is hexamethyldisilazane or trimethylchlorosilane or N,O-bis(trimethylsilyl)acetamide or dimethoxydimethylsilane. According to the method, the product purity is high, the impurity content is low, operation is easy and convenient, refining steps are simplified, production cost is reduced, and the method is suitable for industrial production.

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 preparation method of 5'-adenylic acid. The preparation method of 5'-adenylic acid comprises the following steps: performing synthesis reaction on powdered adenosine and polyphosphoric acid which serve as raw materials under the condition of no solvent, adding pure water after the synthesis reaction to perform hydrolysis, and refining the crude product obtained by the hydrolysis, wherein the mass ratio of the powdered adenosine to the polyphosphoric acid to the pure water is 1:(2-4):(2-4). The preparation method of 5'-adenylic acid has the following advantages: the solvent-free synthesis method is adopted, the reaction impurities are few, the condition is mild and pollution is avoided; the product yield is 90 percent or above, the product content is more than 99 percent and the conversion rate of the raw materials is high; and the operation steps are simple, the raw materials are wide in source and the price is moderate, so the preparation method of 5'-adenylic acid can be popularized and implemented on a large scale.

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.