8 results about "Hemiacetal" patented technology

The present invention relates to a biocatalytic synthesis of esters that can also be implemented on an industrial scale. In particular, the invention relates to a process for the production of esters, via a hemiacetal intermediate, consisting of the following steps: – a step of bringing into contact, in a reaction medium, • a mixture of a C1– Cn alcohol and a C1– Cn aldehyde with an enzymatic catalytic system comprising an oxidized cofactor selected from NAD(P)+ and NAD+ and a polypeptide of the oxidoreductase group having preferential dehydrogenase activity toward the formed hemiacetal and the starting aldehyde, or alternatively • a C1– Cn alcohol with an enzymatic catalytic system comprising an oxidized cofactor selected from NAD(P)+ and NAD+ and a polypeptide of the oxidoreductase group having preferential dehydrogenase activity toward the formed hemiacetal, the starting alcohol, and the formed aldehyde, or alternatively • a C1– Cn aldehyde with an enzymatic catalytic system comprising a reduced cofactor selected from NAD(P)H or NADH and a polypeptide of the oxidoreductase group having preferential dehydrogenase activity toward the starting aldehyde and the formed hemiacetal, where n may be any number, and – a step of isolating the corresponding ester.

This application relates to a MALDI reactive matrix, 5-methoxy-2-hydroxybenzoyl hydrazine, for the analysis of reducing sugars, belonging to the field of sugar biochemical analysis technology. This application provides the application of 5-methoxy-2-hydroxybenzoyl hydrazine as a MALDI reactive matrix in combination with 2,5-dihydroxybenzoic acid in the analysis of reducing sugars. Specifically, 5-methoxy-2-hydroxybenzoyl hydrazine is the reactive matrix, possessing a hydrazine reactive group that can react with the hemiacetal terminus of reducing sugars. 2,5-dihydroxybenzoic acid acts as a catalyst, significantly promoting the efficient reaction between 5-methoxy-2-hydroxybenzoyl hydrazine and reducing sugars. The 5-methoxy-2-hydroxybenzoyl hydrazine / 2,5-dihydroxybenzoic acid composite matrix provided in this application can form a uniform co-crystallization with reducing sugars, exhibiting good signal reproducibility (RSD < 10%) and good linearity in the range of 0.2~20 pmol / μL (R0). 2 > 0.999).

The invention discloses a full-temperature-range liquid phase temperature swing adsorption process for deep dehydration and impurity removal of trioxymethylene, which mainly comprises the following steps: raw material flow, temperature swing adsorption purification, temperature swing adsorption desorption and rectification concentration. The method comprises the following steps: purifying trioxymethylene which is obtained or purchased in a trioxymethylene production process and has the purity of 99.9%, the water content of 500-1000ppm, the content of micromolecular impurity components such as formaldehyde / methanol of 100-300ppm and the content of macromolecular impurity components such as hemiacetal and paraformaldehyde of more than or equal to 50ppm until the purity of the trioxymethylene is more than or equal to 99.999%, the water content of the trioxymethylene is less than or equal to 20-50ppm, and the water content of the trioxymethylene is less than or equal to 20-50ppm; the content of micromolecular impurity components such as formaldehyde and methanol is smaller than or equal to 20-50 ppm, the content of macromolecular impurity components such as methylal and paraformaldehyde is smaller than 20-50 ppm, the problems that the purity of products obtained through existing methods such as special rectification and membrane separation does not reach the standard, and production energy consumption and cost are high are solved, the process is simple, import is replaced, and the method is suitable for industrial production. And the quality requirement of polymer-grade trioxymethylene required by polyformaldehyde production is met.

For example, when used as a material for forming metal oxide thin films, the objective is to provide a metal alkoxide-containing composition that can form metal oxide thin films with fewer cracks and lower surface roughness compared to conventional thin films, even when the thickness is increased. [Solution] A metal alkoxide-containing composition comprising the following component (A) and the following component (B), wherein the mass-based content ratio (A / B) is 70.0 / 30.0 to 99.9 / 0.1. (A) Metal alkoxides with a total of 1 to 40 carbon atoms, (B) A hemiacetal ester of a carboxylic acid consisting of a 1-4 valent carboxylic acid and a vinyl ether, wherein the number of carbon atoms after removing the vinyl group of the vinyl ether is 1-6.

This application discloses a method for preparing a chiral eight-membered ring hemiacetal compound and its reaction with ibuprofen drug molecules, wherein the eight-membered ring compound is shown in any of 1)-4): 1) (5S,7R,12R)-12-oxo-7-(2-oxopropyl)-5H,7H-dibenzo[c,f][1,5]oxothiazine-5-yl acetate; 2) (5S,7R,12R)-3,9-dichloro-12-oxo-7-(2-oxopropyl)-5H,7H-dibenzo[c,f][1,5]oxothiazine-5-yl acetate; 3) (5S,7R,12R)-12-oxo-7-(2-oxohexyl)-5H,7H-dibenzo[c,f][1,5]oxothiazine-5-yl acetate. The invention also discloses a method for preparing this eight-membered ring hemiacetal. The eight-membered ring hemiacetal of the present invention can react with carboxyl-containing drug molecules (ibuprofen), thus serving as a lead drug molecule.

The application relates to the technical field of pharmaceutical chemistry, and discloses a benzazepine bridged ring derivative and a preparation method thereof. The preparation method comprises the following steps: adding a substrate (1.0 eq), a sulfur-substituted benzylpropyl aldehyde (1.5 eq), a base DABCO (0.2 eq) and dry acetonitrile (2.0 mL) into a reaction test tube, mixing the mixture at normal temperature for 24 hours, concentrating and purifying after the reaction is completed to obtain a hemiacetal product 3. Then the hemiacetal product, chloroform (0.5 mL) and H2O (100 muL) are added into the reaction test tube, and stirring is carried out at 60 DEG C for 72 hours. The reaction is monitored to be completed through thin layer chromatography, then the reaction mixture is directly purified through column chromatography to obtain a corresponding target product. The preparation method has the advantages of simple operation, mild reaction and high yield. The derivative provided by the application has good antibacterial activity, and has a wide market application prospect.

The embodiment of the invention relates to a porous carbon material as well as a preparation method and application thereof, and the preparation method comprises the following steps: dissolving a phenol source in an anhydrous polar solution, adding cyclic organosiloxane with a preset size, and stirring, so that the phenol source and the cyclic organosiloxane are uniformly mixed to obtain a first mixed solution; adding organic alkali into the first mixed solution to enable the first mixed solution to be alkalescent, then adding an aldehyde source, and stirring to enable hydroxyl of the phenol source and carbonyl carbon of the aldehyde source to be subjected to an addition reaction to generate hemiacetal; carrying out heat treatment on the hemiacetal to enable the hemiacetal to be subjected to condensation reaction, and then washing and drying to obtain an organic silicon / phenolic resin compound; carrying out carbonization treatment on the organic silicon / phenolic resin compound in an inert atmosphere to generate a carbonized product; washing the carbonized product to remove silicon oxide in the carbonized product to form a pore structure, and then passivating to obtain the porous carbon material.

This invention discloses a low-cost method for preparing 2-chloropyranose-1-yl)-4''-ethoxydiphenylmethane, belonging to the field of pharmaceutical synthesis technology. The method uses a hemiacetal compound of formula I as a substrate, and in an organic solvent, under the action of a heterogeneous solid acid catalyst with a water content of less than 2.0% and polymethylhydrosiloxane with specific parameters, a reduction reaction occurs at -20°C to 25°C, highly selectively preparing the compound of configuration II. This invention ingeniously utilizes the spatial confinement effect formed by the matching of the micropores of the dehydrated solid acid and the macromolecular reducing agent, achieving a breakthrough increase in the diastereomeric excess percentage of the target product to an extremely high level. Simultaneously, it completely eliminates the constraints of the traditional -78°C cryogenic conditions, significantly reducing reagent costs. The catalyst can be easily recovered and reused through solid-liquid separation, and no fluorine- or boron-containing waste liquid is generated, making it highly promising for industrial application.