39results about How to "No racemization" patented technology

The invention discloses a preparation method for chiral 4-chloro-3-hydroxybutyrate. The preparation method specifically comprises: adding chiral chloropropylene oxide, an alcohol, a catalyst into a high-pressure reaction vessel, introducing carbon monoxide, heating for a reaction, and obtaining chiral 4-chloro-3-hydroxybutyrate after the reaction. The preparation method has the advantages of being cheap and easily-available in raw materials, mild in reaction conditions, high in yield, low in cost, and the like. Compared with conventional synthetic methods for chiral 4-chloro-3-hydroxybutyrate, the preparation method employs a reaction with atom economical efficiency of 100%, is environment friendly, low in 'three wastes (waste gas, waste water and industrial residue) ' and applicable to industrial production.

The invention discloses a preparation method of a remazolam key intermediate (3S)-7-bromo-2,3-dihydro-2-oxo-5-(2-pyridyl)-1H-1,4-benzodiazepine-3-methyl propionate, and belongs to the technical field of medical intermediates. Herein, 2-(2-amino-5-bromo-benzoyl)pyridine A and N-Tr-glutamic acid-5-methyl ester are adopted as raw materials, a condensation reaction is performed under the action of a boron-containing reagent to obtain a compound B, then deprotection is performed to obtain a compound C, and finally ring closing is performed under the alkaline low-temperature condition to obtain a compound D. The method is good in process reproducibility, simple, convenient and stable to operate, easy to separate products in each step, high in yield, environment-friendly and suitable for industrial large-scale production.

The invention discloses a method for extracting synephrine from ripe navel orange peels. The method comprises the steps as follows: (1) dried navel orange peels are crushed and then mixed with distilled water, complex enzyme is added for enzymolysis, and an enzymolysis mixture is obtained; (2) the enzymolysis mixture is subjected to ultrahigh-pressure enzyme deactivation treatment, the pH is adjusted to 5.0-6.0, subcritical extraction is performed under nitrogen protection, centrifugation is performed after extraction, and a liquid supernatant is collected; (3) the liquid supernatant obtainedin the step (2) is subjected to ultrafiltration separation with an ultrafiltration membrane with the molecular interception being 5,000 u-10,000 u, and a concentrated solution is collected; (4) the concentrated solution obtained in the step (3) is mixed and stirred with ethanol, the obtained mixed solution is subjected to reduced pressure suction filtration and freeze drying, and synephrine is obtained. The method has the advantages of being high in extraction rate and extraction efficiency, mild in treatment condition, environmentally friendly and the like.

The invention discloses a method for reducing amide compounds, which reduces various amides through low valent tiron. Low valent tiron prepared by reducing titanium tetrachloride through magnesium powder is reacted with amide in tetrahydrofuran at 0 DEG C or normal temperature so as to obtain corresponding amine. The method has the advantages that the reaction condition is mild, reagent adopted is chip and easy to get, the method is convenient to operate, substrate has a wide applicable scope, functional group has good compatibility, the reaction is rapid, and the yield is high.

The invention discloses a novel labeling reagent 4-(N,N-dimethylamino)azobenzene-4'-sulfonyl fluoride capable of derivatization reaction with protein and amino acid and its synthesis method and the compound in protein, The application in amino acid analysis, the synthesis method of its intermediate p-acetamidobenzenesulfonyl fluoride and the application of this compound in protein and amino acid analysis. The labeling reagent uses aniline as a raw material to prepare p-acetylaminobenzenesulfonyl fluoride through acetylation, chlorosulfonation and fluorination reactions, and then hydrolyzes the p-acetylaminobenzenesulfonyl fluoride, undergoes diazotization and coupling reactions. The labeling reagent is easy to synthesize, easy to store, derivatizes with primary or secondary amino acids under mild conditions, stable derivatized products, convenient liquid phase or capillary chromatographic separation, high instrument response value, and detection sensitivity up to pmol level. Achieve the effect of chemical derivatization-instrumental detection.

The invention discloses a method for preparing furanone compounds, and provides a method for preparing a furanone compound III. The method includes the following steps that in a solvent, in the presence of inorganic salt, a compound II and a reducing agent are subjected to a reduction reaction, and the furanone compound III is obtained; the solvent is a fatty alcohol solvent or a mixed solvent of a fatty alcohol solvent and water. The brivaracetam can be prepared with the furanone compound III only with the three steps, and the synthetic route is short; the ee value of the compound II is larger than 99.0%, racemization does not occur in the reaction process, and the de value of a brivaracetam I crude product is larger than 99.0%; the brivaracetam I crude product is further purified through a crystal instead of a chirality high-pressure-liquid-phase preparing column, and the chirality purity of brivaracetam I can be further increased to be the de value of 99.80% or above; meanwhile, the content of other individual impurities of the brivaracetam I is smaller than 0.1%, and reaches the API level, and the method is suitable for industrial production. The formula is defined in the description.

The invention discloses a synthesizing process of (S)-2-benzyloxy-pentan-3-one. The synthesizing process comprises the following steps: (1) mixing ethyl lactate with nafoxidine in proportion and performing a reflux reaction for 12 to 48 hours, thereby generating an amide compound; (2) mixing the amide compound with benzyl chloride, alkali and a solvent and reacting, cooling to normal temperature after the reaction, washing an organic layer by using water, concentrating the organic layer under reduced pressure and removing primary distillates, thereby obtaining benzyl-protected amide; and (3) dripping a tetrahydrofuran solution of the benzyl-protected amide into a tetrahydrofuran solution of ethylmagnesium bromide and reacting, adjusting the pH value by using an acid solution after the reaction, extracting a water layer after layering, combining the organic layers, drying, filtering and concentrating filtrate until the filtrate becomes dry, thereby obtaining (S)-2-benzyloxy-pentan-3-one. The synthesizing process is relatively simple to operate, high in safety and low in raw material cost, thereby satisfying the industrial amplification requirement.

The invention discloses a method for extracting synephrine from ripe navel orange peel, which comprises the following steps: (1) crushing the dried navel orange peel and mixing it with distilled water, adding a compound enzyme for enzymolysis to obtain an enzymolysis mixture; 2) The enzymolysis mixture is subjected to ultra-high pressure deactivation treatment, and the pH is adjusted to 5.0-6.0, and then subcritical extraction is carried out under the protection of nitrogen, and the supernatant is collected by centrifugation after extraction; (3) The molecular cut-off is 5000u~ A 10000u ultrafiltration membrane is used to perform ultrafiltration separation on the supernatant obtained in step (2), and collect the concentrate; (4) mix and stir the concentrate obtained in step (3) with ethanol, and the resulting mixture is filtered under reduced pressure and frozen Dry to get synephrine. The method has the advantages of high extraction rate and extraction efficiency, mild treatment conditions, and environmental friendliness.

A prepartion method of N-acetyl-L-carnosine, relates to pharmaceutical intermediates synthesis technology field. Dissolving p-nitrophenol into organic solvent, reacting with acetyl chloride to obtain active ester solution at the presence of acid-binding agent; dissolving the L-carnosine and protection agent into water to obtain aqueous solution, then adding the avtive ester solution into the aqueous solution for reacting, and when the reaction is finished, demixing, decoloring the water layer and decompressing condensing to pulpous state, then mixing the condensed residue with acetate acid andadding into polar solvent for stirring, cold separating and drying to obtain the N-acetyl-L-carnosine. The advantages are: the molar yield is more than 90%, the chemical purity is more than 90%, therefore high yield and ideal purity is suitable for industrial production.

The invention relates to the field of medicines, and in particular relates to a method for preparing a key intermediate (II) of a medicament. The method is characterized in that the key intermediate is prepared by a reaction of a compound IV and phosphorus oxybromide. According to the preparation method, the defects that a compound II is prepared by using a column chromatography in the prior art and large-scale industrial production is difficult to realize by the prior art can be overcome, the key intermediate can be directly prepared by a re-crystallization or reduced-pressure distillation method, and the key intermediate is high in purity.

The invention discloses a method for preparing levodopa by enzymatic method. Insert 3 to 10% of the inoculum into the fermentation medium for fermentation and culture, centrifuge after fermentation, and collect the bacterial cells; add tyrosine and bacterial cells to the buffer solution, at 18 to 30°C, pH5. Under the condition of 0-6.0, the enzymatic reaction is carried out to convert tyrosine into levodopa. In the conversion process, the present invention adopts static cell conversion technology, preferably intermittent weak ventilation technology, which improves the catalytic efficiency of the enzyme, the concentration of levodopa can reach 27g / L, and the molar conversion rate of tyrosine can reach more than 99%, and Mild conditions, high enantiomer selectivity, no racemization, more suitable for industrial production, with significant economic benefits and industrial application value.