20 results about "Hemiacetal" patented technology

The invention discloses a compound containing a bicyclic hemiketal structure and a preparation method thereof, alkynyl allyl carbonate is used as a raw material, in the presence of a nucleophilic catalyst, alkynyl allyl carbonate reacts with a benzoylacetonitrile derivative, ABB'multi-component reaction is carried out through a continuous [5 + 1] / addition / cyclization reaction sequence, and the compound containing the bicyclic hemiketal structure is obtained. Bicyclic hemiketal derivatives commonly seen in natural product structures are obtained with good to excellent diastereoselectivity. The method has the advantages of good diastereoselectivity products, excellent chemical selectivity, greenness, mild reaction conditions, convenience in operation, few byproducts and the like, the synthesis steps are good in economy, and four chemical bonds and three continuous chiral centers are simultaneously constructed through one-step operation. Meanwhile, the compound with the bicyclic hemiketal structure has important application value in multiple fields of medicinal chemistry, natural product chemistry, traditional Chinese medicine chemistry and the like, and an efficient preparation means and a series of candidate compounds are provided for development of functionality or biological activity of related compounds with the bicyclic hemiketal / hemiacetal structure.

The invention relates to the technical field of biological engineering and biological catalysis, in particular to two alcohol dehydrogenase mutants and application thereof. The invention discloses a pair of alcohol dehydrogenase mutants CpAR2-M3 (F85A / F192L / E209A) and CcPAR-M1 (V158L) with opposite stereoselectivity, wherein the corresponding amino acid sequences of the alcohol dehydrogenase mutants CpAR2-M3 (F85A / F192L / E209A) and CcPAR-M1 (V158L) are respectively shown as SEQ ID No.5 and SEQ ID No.6. The invention further discloses a preparation method of the alcohol dehydrogenase mutants. The method can be applied to asymmetric reduction of hemiacetal compounds, synthesis of corresponding key intermediate axial chiral biaryl benzyl alcohol compounds with complementary stereoselectivity is achieved, the highest yield can reach 95%, the highest stereoselectivity can reach 99% e.e., and the method is suitable for industrial production. A green, efficient and high-stereoselectivity synthesis strategy is provided for subsequent enantiocomplementary synthesis of the compounds.

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.

The invention belongs to the technical field of hydrogel preparation, and relates to a preparation method and application of metabolism programming hydrogel, and the preparation method comprises the following steps: 1, oxidizing dextran Dex through sodium periodate NaIO4 to generate oxidized dextran ODex rich in aldehyde; 2, under the protection of nitrogen, carrying out amino dynamic Schiff base reaction of APTC and carrying out covalent binding with an aldehyde group of oxidized dextran ODex to form ODex-APTC; 3, mixing ODex-APTCC and CMC GOx solutions at room temperature to form hydrogel based on hemiacetal crosslinking and a hydrogen bond mechanism; according to the invention, autonomous'antibacterial repair 'dual-phase switching is realized through metabolic microenvironment reprogramming; in the stage of wound surface high-glucose infection, the hydrogel utilizes a diabetes wound surface high-glucose environment as an endogenous fuel, and glucose reduction, active oxygen mediated sterilization and microenvironment acidification are realized at the same time through reaction of glucose oxidase and glucose; when glucose oxidase reacts, the acid environment triggers a controlled H2S release program, and wound healing is accelerated by relieving oxidative stress and activating a regeneration signal channel.

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).

1. A method for reducing the amount of HS in a liquid or gas stream, the method comprising: a) operating an industrial process having HS in a liquid or gas stream, or in both the liquid and gas streams associated with the industrial process, the industrial process comprising connecting pipes that allow liquids and gases to move from one location to another within the process; b) injecting a silica nanoparticle mixture into a liquid or gas stream, or in both the liquid and gas streams associated with the industrial process, the silica nanoparticle mixture being in a colloidal or dry state; and c) providing a material in the silica nanoparticle mixture to react with the HS to result in a reduction of HS in the liquid or gas product fluid. In certain embodiments, the silica nanoparticle mixture comprises silica nanoparticles, with or without a surface treatment, and one or more chemicals selected from the group consisting of triazines, alcohols, polyols, ketones, aldehydes, and hemiacetals.

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.

The invention belongs to the technical field of doxycycline, and particularly relates to a veterinary drug doxycycline composition and a preparation process thereof, the veterinary drug doxycycline composition comprises 24%-26% of methanol, 3.5%-6.5% of oxytetracycline base, 0.03%-0.1% of methanol ammonia, 1.7%-3.2% of NBS, 24%-26% of 11 alpha-bromine-6, 12-hemiketal oxytetracycline, 7%-8% of HZSM-5, 24%-26% of toluenesulfonic acid and 3%-4% of palladium on carbon, the veterinary drug doxycycline composition further comprises catalysts, the catalysts comprise 2.7%-3.2% of titanium tetraisopropylate and 3.07%-4% of S-diphenol, and the reaction temperature is controlled to be 30-50 DEG C; the preparation method comprises the following steps: sequentially putting 100g of methanol, 10g of oxytetracycline base and 0.1 g of methanol ammonia into a reaction bottle, stirring for 30 minutes in an environment of 20-30 DEG C by using an ultrasonic stirrer, starting to cool to-10 to-15 DEG C, adding 5g of dried and crushed NBS, and carrying out dechlorination and asymmetric hydrogenation by using a self-made palladium-carbon catalyst, so that the yield and the chemical and stereoselectivity of the reaction are remarkably improved, the total yield reaches 53%, and the yield is up to 90%. The method has the advantages of high yield, good product quality and the like, and the doxycycline primary liquid is heated by heating equipment and lasts for a fixed time, so that the drug property of the doxycycline primary liquid is enhanced at a specific temperature, and the adverse reaction of drugs to animals is reduced.

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 discloses a production device and a production method of a condensation alcohol, wherein ethylene glycol is subjected to six units of a condensation reaction, separation and refining, esterification reaction, esterification separation, hydrolysis reaction and hydrolysis separation, so that the production and refining of diethylene glycol prepared by dehydration and condensation of ethylene glycol are realized, the process conversion rate is improved through by-product treatment, and the separation difficulty is reduced. The production process disclosed by the application is continuous and easy to operate, and has industrial feasibility.

The invention is directed to a crosslinkable flame-retardant coating composition comprising the following components:a) a dendritic polymer having hydroxyl groups, wherein the dendritic polymer has a hydroxyl number in the range of 80 to 800,b) a polyol having at least 3 hydroxyl groups,c) an ammonium polyphosphate compound,d) a base coat polymer selected from a polycarbamate resin or a polymer bearing carboxyl groups, ande) a crosslinker for crosslinking the base coat polymer selected from a compound having two or more aldehyde groups, acetals or hemiacetals of the aldehydes, or a polycarbodiimide.Such a cross-linkable flame-retardant coating composition improves the overall appearance of the cross-linked base coating on a substrate and also imparts improved flame-retardancy.

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 present invention relates to an undercoat composition for an optical film and a method for preparing the same. The composition comprises the following components in parts by weight: 85-95 parts of double-bond modified waterborne polyurethane with the solid content of 30%, 2-10 parts of a crosslinking agent containing silicon-hydrogen bonds and 1-5 parts of a platinum catalyst. The double-bond modified waterborne polyurethane is prepared by carrying out pH regulation, mixing and heating reaction on an aldehyde solution obtained by hydrolyzing an acetal or hemiacetal compound and a waterborne polyurethane emulsion, and carrying out post-treatment to remove small-molecule byproducts, so as to obtain the high-solid-content modified emulsion. The priming coat working solution is coated on the surface of a PET base material, and after drying and thermocuring, a compact cross-linked structure is formed through a hydrosilylation reaction. According to the invention, the adhesive force between the PET substrate and the acrylate optical resin layer is effectively enhanced, the problem that the original interface is insufficient in bonding force and easy to layer is solved, meanwhile, the process is simple and convenient, the raw material source is wide, and the method is suitable for a brightness enhancement film product for display.

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.

A process for preparing alkyl methacrylate is provided, comprising reacting methacrolein with an alkyl alcohol in an oxidative esterification (OER) system in the presence of at least one inhibitor, an oxygen-containing gas, and a noble metal-containing catalyst to produce an OER product stream, wherein the OER product stream comprises alkyl methacrylate, alkyl isobutyrate in an amount ranging from 0.1 to 5000 ppm, and at least one Michael addition product in an amount ranging from 0.01 to 5 wt %, based on the total weight of the OER product stream. The OER product stream is fed to an alcohol recovery distillation column to provide an overhead stream comprising the alkyl alcohol and methacrolein, and a bottoms stream comprising the alkyl methacrylate, alkyl isobutyrate, and acetals and / or hemiacetals of methacrolein. The bottoms stream from the alcohol recovery distillation column is fed to an acetal hydrolysis reactor and a phase separator.

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.

The application belongs to the field of organic synthesis and medicinal chemistry, and relates to synthesis and AhR inhibitory activity research of quinoid diterpenyl benzene styrene alcohol ester adducts. The compound of the application has a structure shown in general formula (I), tanshinone is used as a raw material, and quinoid diterpenyl benzene styrene alcohol ester adducts are synthesized through eight steps. The raw material of the application is easy to obtain, and the reaction is easy to control. The application has important reference significance for preparing benzene 1,4-dioxane hemiacetal compounds. The prepared quinoid diterpenyl benzene styrene alcohol ester adducts have significant AhR inhibitory activity, and can be used as tumor immunotherapy drugs for further drug preparation.

The application discloses a preparation method of a bimetallic supported catalyst and a method for preparing a hemiacetal from a furan aldehyde and an alcohol, and the preparation method of the bimetallic supported catalyst comprises the following steps: mixing a carrier Y and a precursor salt of an active metal M1, standing at room temperature and drying to obtain a solid A; calcining the solid A under an air atmosphere to obtain a solid B; mixing a precursor salt of an active metal M2, the solid B and deionized water, regulating the acid-base property of a mixed solution, adding a hydrogen donor reducing agent, loading the active metal M2 on the solid B by using a hydrogen donor reduction method, and filtering and drying a product to obtain the bimetallic supported catalyst. The catalyst loaded with two active metals is prepared by using the preparation method, the catalyst has high stability, the two active components play a synergistic role, the activity of the catalyst is improved, and the method has high conversion rate and high selectivity for the hemiacetal reaction.

The invention relates to the technical field of PBO fiber modification, in particular to a plasma synergistic polyvinyl alcohol (PVA) and glutaraldehyde (GA) graft modified PBO fiber and a preparation method thereof.The plasma synergistic polyvinyl alcohol (PVA) and glutaraldehyde (GA) graft modified PBO fiber is prepared, a mixed solution prepared through double solvents is adopted to clean dust and oil on the surface of the PBO fiber, clean PBO fiber is prepared, the plasma activated PBO fiber is soaked in an acidic polyvinyl alcohol solution, and the PBO fiber is prepared through a two-step method. According to the preparation method, polyvinyl alcohol macromolecules are uniformly and firmly grafted on the surface of the PBO fiber, hemiacetal reaction of PVA and GA is carried out to generate ether bonds, a compact interfacial film rich in ether bonds is formed, the hydrophilicity of the surface of the GA-coated PVA / PBO fiber is obviously improved, and the surface water contact angle is obviously reduced to 0 degree.