52results about How to "Good optical selectivity" patented technology

The invention provides a novel preparation technology of a tasimelteon intermediate namely (1R,2R)-(2,3-dihydrobenzofuran-4-yl)cyclopropyl formic acid. The technology comprises the following steps: (1) carrying out reactions between 2,3-dihydrobenzofuran-4-formaldehyde and malonic acid in the presence of piperidine to generate 2,3-dihydrobenzofuran-4-acrylic acid; (2) converting 2,3-dihydrobenzofuran-4-acrylic acid into acyl chloride in the presence of thionyl chloride, then reacting the acyl chloride with L-menthol to generate 2,3-dihydrobenzofuran-4-acrylic acid L-menthol; (3) carrying out reactions between 2,3-dihydrobenzofuran-4-acrylic acid L-menthol and dimethyl sulfur oxide in the presence of sodium hydroxide to generate (1R,2R)-(2,3-dihydrobenzofuran-4-yl)cyclopropyl formic acid L-menthol; (4) hydrolyzing the (1R,2R)-(2,3-dihydrobenzofuran-4-yl)cyclopropyl formic acid L-menthol in the action of a sodium hydroxide water solution so as to obtain the (1R,2R)-(2,3-dihydrobenzofuran-4-yl)cyclopropyl formic acid. The novel preparation technology is developed on the basis of the conventional technologies, and has the advantages of easily-available raw materials, low cost, simple operation, and suitability for industrial massive production.

The invention belongs to the field of solar energy selective absorption anti-reflection materials, and particularly relates to a thermal sprayed coating anti-reflection protective layer applicable toselective absorption of medium and high-temperature solar energy and a preparation method of the thermal sprayed coating anti-reflection protective layer. The thermal sprayed coating anti-reflection protective layer consists of an inner layer and an outer layer which are compounded, wherein the inner layer is prepared from 40 weight percent of a high-absorption Co3O4-CoAl2O4 thin film, and the outer layer is prepared from 20 weight percent of low-absorption Co3O4-CoAl2O4. The thermal sprayed coating anti-reflection protective layer prepared by the preparation method disclosed by the inventionnot only has excellent optical selectivity, but also can relieve the stress action of the coating in a thermal treatment process, reduce the porosity of a thermal sprayed coating and increase an absorption-emission ratio of the coating, is relatively high in thermal stability at high temperature, also achieves protection, connection and anti-reflection effects, and is compact in structure and stable in performance.

The invention relates to a method for enzymatically synthesizing (S)-2-aminobutanamide, and belongs to the technical field of pharmaceutical intermediate synthesis. In order to solve the existing problem of adopting chemical synthesis method, a method for enzymatic synthesis of (S)-2-aminobutanamide is provided, the method comprises in the presence of an amino donor, under the action of a catalytic amount of lipase, The substrate (S)-2-aminobutyric acid methyl ester is subjected to catalytic aminolysis to obtain the corresponding product (S)-2-aminobutyramide; the gene sequence of the lipase is shown in SEQ ID NO.1. The present invention has high stereoselectivity and specificity, forms a product of S-type chiral configuration, and has the effects of high chiral purity and high ee value of the product.

The invention relates to polycarbonate with optical activity and a preparation method thereof, belonging to the technical field of polymer synthesis. A repetitive unit of the polycarbonate is shown in the description, wherein R1-R3 are -H or alkyl. The preparation method of the polycarbonate comprises the following steps: dispersing an epoxide and a catalyst into an organic solvent, and performing a carbon dioxide bubbling reaction for 30-40h, thus obtaining the polycarbonate; the epoxide is shown in the description. The prepared polycarbonate has optical activity, a number-average molar mass of more than 3000, and a vitrification transformation temperature being more than 150 DEG C, maximally 272 DEG C, and the polycarbonate can be used as a high temperature-resistant polymer material and be applied to fields with harsh work environments. The preparation method can be implemented under room temperature, the pressure requirement on carbon dioxide is very low, reaction conditions are mild, the optical selectivity is high, and a prepared product has extremely high optical purity and wide industrial promotion value.

The invention discloses a sacubitril intermediate and a preparation method of the sacubitril intermediate and sacubitril, and belongs to the technical field of organic synthesis of drugs. On one hand, the invention discloses a novel compound-sacubitril intermediate compound B and a preparation method thereof, and on the other hand, the invention discloses a novel preparation method of the sacubitril. The sacubitril intermediate and the preparation method of the sacubitril intermediate and the sacubitril have the following advantages that the synthesizing route is short, the product can be prepared only through four steps of chemical reactions, and the steps of existing patent routes all exceed nine steps; the dicarbonyl compound is prepared through Reformasky condensation supplied by the method, and the cost is low; a first chiral center is introduced by fully utilizing a chiral compound L-(S)-ethyl lactate which is low in cost and easy to obtain in the natural world, and the cost is low; a second chiral center is constructed through a biological enzyme catalysis technique, the optical selectivity reaches up to 99.9%, the quality is good, and the cost is low. By means of the technological means, the total yield of the prepared sacubitril is increased, and the quality of the sacubitril is improved.

The invention discloses a chiral organic selenium-sulfur catalyst and its preparation method and use in an asymmetric reaction. The chiral organic selenium-sulfur catalyst is prepared from commercial and low price chiral amino-indanol through high efficiency multi-step synthesis. The preparation method has simple processes and is convenient for operation. The chiral organic selenium-sulfur catalyst based on an organic indene skeleton has a wide application range, good catalysis effects in many organic reactions and excellent enantiomer selectivity. The chiral organic selenium-sulfur catalyst has excellent optical selectivity in an asymmetric trifluoromethylthioesterification reaction, opens the ancient river of an alkene asymmetric trifluoromethylthioesterification reaction and has high catalysis efficiency and good enantioselectivity.