8results about How to "High molar yield" patented technology

The invention discloses an asymmetric synthesis method of an efinaconazole intermediate, which comprises the following steps: adding auxiliary materials and water into a reaction bottle, then adding hydrogen peroxide, controlling a certain temperature to dropwise add an organic solution of a substrate I and a catalyst II into the reaction bottle, controlling a certain temperature to carry out a heat preservation reaction, and carrying out post-treatment to obtain a product III. The target product is obtained through the proper chiral catalyst, and the method is mild in condition and high in chiral selectivity.

The invention discloses a continuous production method of diazonium salt, which belongs to the technical field of organic synthesis and comprises the following steps: preparation of a reaction accelerator, equipment preparation, raw material preparation and reaction. The equipment preparation comprises the following steps: filling a mixture of a reaction accelerant and quartz sand into a second tubular reactor, then connecting a first tubular reactor with the second tubular reactor in series, and connecting an outlet of the first tubular reactor with an inlet of the second tubular reactor; according to the production method, continuous production of the diazonium salt can be achieved, meanwhile, the use amount of acid can be reduced, and the purity and yield of the prepared diazonium salt are improved.

This invention relates to the field of organic compound preparation technology, specifically a method for preparing 11-triglycerides of carbonate via low-temperature acylation. This method uses glycerol and undecanoyl chloride as raw materials, employing a synergistic system of a "composite acid-binding agent + Lewis acid catalyst," and combines in-situ dehydration technology and a stepwise heating strategy in a dual-solvent environment to achieve efficient synthesis. The specific steps include: under nitrogen protection, dissolving glycerol in a dichloromethane-toluene dual solvent, adding a composite acid-binding agent of pyridine and N,N-diisopropylethylamine, anhydrous zinc chloride catalyst, and 4A molecular sieve for in-situ dehydration; dropwise adding undecanoyl chloride at a low temperature of 5-10°C, followed by sequential heating to 30°C for 2-3 hours and then reacting at 50°C for 12-16 hours; and post-processing using a combined process of filtration-multi-stage extraction-membrane separation-column chromatography. This invention provides mild reaction conditions, effectively suppresses side reactions, produces high-purity products, increases molar yield, and reduces solvent toxicity and purification costs.

The invention discloses a method for preparing cefalonium through catalysis of immobilized penicillin G acylase. According to the method, immobilized penicillin G acylase is used as a catalyst, 7-IACA and 2-thiophenemethyl acetate are catalyzed to react in a mixed system of water and an organic solvent, and cefalonium is prepared. The organic solvent is one or more of ethanol, methanol and acetone. The preparation method disclosed by the invention is simple to operate, mild in reaction condition, suitable for industrial production and environment-friendly; the used immobilized penicillin G acylase can be repeatedly used, so that the production cost can be reduced; the molar yield of the cefalonium is high, the purity is 99% or above, impurities are few, the quality is high, and compared with a chemical preparation method, the cefalonium preparation method has obvious advantages.

The invention discloses a synthesis method of 2-mercapto-5-methyl-1, 3, 4-thiadiazole, and belongs to the technical field of organic synthesis. The synthesis method of the 2-sulfydryl-5-methyl-1, 3, 4-thiadiazole comprises the following steps: mixing free sulfonic acid and phosphorus oxychloride, heating to 90-115 DEG C, and carrying out a reflux reaction; then cooling to 50-60 DEG C, and decompressing to remove phosphorus oxychloride; cooling to below 35 DEG C, adding dichloromethane for dissolving and dispersing, and then adding ethanol for dispersing to obtain a 2-chloro-5-methyl-thiadiazole ethanol solution; the preparation method comprises the following steps: mixing a 2-chloro-5-methyl-thiadiazole ethanol solution with thiourea, heating to 65-85 DEG C, and carrying out a heat preservation reaction to obtain the 2-mercapto-5-methyl-1, 3, 4-thiadiazole. The molar yield of the 2-mercapto-5-methyl-1, 3, 4-thiadiazole synthesized by the method disclosed by the invention is up to 80-85%, and the product purity is up to 99% or above.

The invention provides a high-yield clean synthesis process of thiamethoxam, and relates to the technical field of pesticide fine chemical synthesis, and the process mainly comprises the following steps: Sp1, destroying crystal lattices of 3-methyl-4-nitroimido-perhydro-1, 3, 5-oxadiazine by using an ultrasonic cavitation technology, forming a low-temperature high-activity suspension in the presence of micronized inorganic base, and breaking through the bottleneck of solid-liquid mass transfer; the preparation method comprises the following steps: constructing an efficient nucleophilic system by using a quaternary ammonium salt and open-chain polyether composite catalyst; 2-chloro-5-chloromethylthiazole is introduced by adopting a two-way gradient feeding strategy combining low-temperature slow dropping and high-temperature fast dropping, reaction kinetics is accurately controlled, and decomposition of heat-sensitive raw materials is effectively inhibited; sp4, cleaning post-treatment is achieved through hot filtration desalination, mother liquor circulation and solvent recovery. The method effectively solves the problems of low yield and more impurities in the traditional high-temperature process, the molar yield of thiamethoxam can be stabilized at 96% or above, the product purity is high, the whole-process clean production is realized, and the method has remarkable industrial application value.

The present invention belongs to the field of enzyme catalysis technology, and is specifically related to a kind of amine dehydrogenase, gene, recombinant bacteria, amine dehydrogenase crude enzyme liquid, dehydrogenase composition, dehydrogenase crude enzyme liquid composition and preparation method of (R) 3-aminobutanol. The present invention constructs an amine dehydrogenase with high selectivity and high activity, and the amine dehydrogenase is combined with formate dehydrogenase as a catalyst to provide a method for preparing chiral (R) 3-aminobutanol. The inventive method does not require a large amount of cofactors, improves the conversion rate and product yield of raw materials, and the chiral product prepared at the same time has high selectivity and ee value greater than 99.9%. In addition, the inventive method simplifies downstream separation and refining process, is a new process of simple process and green environmental protection, and has the potential for industrialization and good application prospects.

The invention discloses a preparation method of a rosuvac intermediate, and belongs to the technical field of medicine synthesis. The preparation method of the rosuvavar intermediate comprises the following steps: S1, mixing an intermediate D4, organic alkali, methyl mercaptothiadiazole, DMF (Dimethyl Formamide) and an aluminum salt catalyst, heating to 95-125 DEG C, carrying out a first heat preservation reaction, carrying out phase separation, and adding dichloromethane for reverse extraction to obtain a dichloromethane solution of an intermediate D4-1; the molar yield of the intermediate D4-1 can reach 97% or above.