65 results about "Ethyl acetoacetate" patented technology

The invention relates to the technical field of organic synthetic chemistry, in particular to a preparation method of ethyl 2-n-butyl acetoacetate, which comprises the following specific steps: S1, preparation of a composite solid base catalyst, S2, synthesis of ethyl 2-n-butyl acetoacetate, S3, post-treatment of a reaction solution, and S4, separation and purification of a product. The preparation method has the following beneficial effects that the magnesium-aluminum composite oxide is used as a carrier, and the composite solid base catalyst loaded with potassium and lanthanum has relatively high catalytic activity and selectivity; the magnesium-aluminum composite oxide carrier has a relatively large specific surface area and rich alkaline sites, so that a good catalytic environment is provided for the reaction; as a main active component, potassium ions can effectively activate alpha-active methylene of ethyl acetoacetate and promote formation of negative ion intermediates; the introduction of lanthanum ions can adjust the electronic structure of the catalyst, enhance the stability of the active center and inhibit the occurrence of side reactions.

The invention discloses lithium-free high-heat-resistance ceramic pug and a preparation method thereof, and relates to the technical field of ceramic materials. When the lithium-free high-heat-resistance ceramic pug is prepared, aluminum oxide reacts with 3-(2, 3-epoxypropoxy) propyltrimethoxysilane to prepare pre-modified aluminum oxide; reacting the pre-modified aluminum oxide with starch to obtain modified aluminum oxide; mixing ethyl acetoacetate, isopropanol, zirconium oxychloride, aluminum sec-butoxide, polyvinylpyrrolidone and N-N dimethylformamide to prepare a spinning solution, performing electrostatic spinning, and then immersing the spinning solution into the yttrium oxide sol to prepare aluminum oxide-zirconium oxide-yttrium oxide composite fibers; stirring and mixing the modified aluminum oxide, talc, aluminum oxide-zirconium oxide-yttrium oxide fibers, hydroxypropyl methyl cellulose, glycerol, oleic acid, polyethylene glycol and water, and performing vacuum pugging to obtain the lithium-free high-heat-resistance ceramic pug. The lithium-free high-heat-resistance ceramic pug prepared by the invention has good thermal shock resistance and bending strength after being sintered.

The application belongs to the technical field of ink, and discloses a UV touch ink and a preparation method thereof.The UV touch ink comprises a UV modified acrylate, an acetylacetate ethyl ester-containing acrylic resin, an active monomer, an organic wax, a photoinitiator and a solvent; the active monomer is selected from at least one of dipropylene glycol diacrylate, diethylene glycol phthalate diacrylate, neopentyl glycol diacrylate and hexanediol diacrylate. The UV modified acrylate, the acetylacetate ethyl ester-containing acrylic resin, the active monomer and the organic wax are used as main components, and the selection of the active monomer enables the prepared UV touch ink to have excellent skin feeling and velvet feeling effects, and excellent adhesion, light resistance, weather resistance, alcohol resistance and solvent resistance. Meanwhile, the UV touch ink can simplify the curing process, and only needs to be dried by UV after printing, has high curing efficiency, and does not need to be dried by hot air and UV.

This invention relates to the field of hafnium carbide technology and discloses a thermal decomposition preparation process for hafnium carbide precursors. The process includes: dissolving hafnium tetrachloride in anhydrous ethanol, adding propylene oxide dropwise for neutralization and acid removal to obtain a neutral ethanol-hafnium precursor solution; adding ethyl acetoacetate methacrylate and heating for coordination to obtain a hafnium coordination monomer solution; adding acrylonitrile and an initiator and heating for polymerization; when the viscosity of the reaction solution increases, injecting a dimethyl sulfoxide hot solution of melamine as a locking liquid; precipitating, separating, and drying to obtain the hafnium carbide precursor; and after oxidative crosslinking treatment, calcining at high temperature under an inert atmosphere to undergo carbothermic reduction to obtain hafnium carbide powder. This invention achieves molecular-level dispersion of precursor components through liquid-phase coordination and in-situ network locking, effectively reducing the reaction temperature and inhibiting grain agglomeration, thus producing high-purity, ultrafine hafnium carbide powder.

The present application relates to a kind of preparation method of trifluoromethyl pyrazole compound, belong to the technical field of organic synthesis.The specific method is: (1) trifluoroacetyl ethyl acetate is first with hydrazine hydrate cyclization reaction and generates compound of formula III;(2) under the catalysis of base, compound of formula III is reacted with difluoromethylation reagent and generates compound of formula II;(3) compound of formula II is reacted with methylating agent and obtains compound of formula I;The difluoromethylation reagent is difluoro-monochloromethane or sodium difluoro-monochloroacetate;The methylating agent is chloromethane, bromomethane, iodomethane, dimethyl sulfate or dimethyl carbonate.The present application is prepared by changing reaction route, and the higher-priced raw material methylhydrazine is replaced, and isomer impurity is no longer generated in the product prepared.Not only raw material cost is reduced, but also the purity of product is improved.

The application discloses a lithium-free high-heat-resistant ceramic mud and a preparation method thereof, and relates to the technical field of ceramic materials. In the preparation of the lithium-free high-heat-resistant ceramic mud, alumina is reacted with 3-(2,3-epoxypropoxy) propyl trimethoxysilane to obtain pre-modified alumina; the pre-modified alumina is reacted with starch to obtain modified alumina; ethyl acetoacetate, isopropyl alcohol, zirconium oxychloride, aluminum sec-butoxide, polyvinylpyrrolidone and N-N dimethylformamide are mixed to form a spinning solution, the spinning solution is electrospun, and then immersed in yttrium oxide sol to obtain alumina-zirconia-yttria composite fibers; the modified alumina, talc, alumina-zirconia-yttria fibers, hydroxypropyl methyl cellulose, glycerol, oleic acid, polyethylene glycol and water are stirred and mixed, and vacuum pugging is carried out to obtain the lithium-free high-heat-resistant ceramic mud. The lithium-free high-heat-resistant ceramic mud prepared by the application has good thermal shock resistance and bending strength after sintering.

The application belongs to the technical field of organic synthesis and particularly relates to a preparation method of 1-methyl-3-(trifluoromethyl)-1H-pyrazol-5-ol, which comprises the following steps: (1) adding acid into a reaction container, adding 40% methylhydrazine aqueous solution and stirring uniformly; (2) adding trifluoroacetyl acetic acid ethyl ester dropwise into the reaction system of step (1), heating after dropwise addition is completed, performing heat preservation reaction and monitoring the reaction by TLC; (3) after the reaction is completed, adding water into the reaction system of step (2) to perform crystallization, performing suction filtration after cooling, washing the filter cake with water and drying to obtain 1-methyl-3-(trifluoromethyl)-1H-pyrazol-5-ol crude product, and purifying to obtain the final product 1-methyl-3-(trifluoromethyl)-1H-pyrazol-5-ol. The application has the beneficial effect that by controlling the feeding sequence, the acid amount and the reaction temperature, the methylhydrazine addition amount is reduced, methylhydrazine is avoided from being left in waste water, and thus the treatment difficulty of waste water is reduced.

This invention relates to a silicone rubber adhesive and its preparation method, belonging to the technical field of silicone rubber adhesives. The silicone rubber adhesive comprises the following components: 100 parts of hydroxyl-terminated polydimethylsiloxane and nano-calcium carbonate, of which 40 to 60 parts are nano-calcium carbonate; 2 to 3 parts of methyltrimethoxysilane; 1 to 2 parts of diisopropyl bis(ethyl acetoacetate) titanate; and 0.3 to 0.7 parts of a tackifier. The tackifier comprises compounds with the general structural formula shown in Formula I or Formula II. Compared with existing silicone rubber adhesives, the silicone rubber adhesive provided by this invention contains a tackifier with a specific structure, which can significantly improve the construction speed, meet the needs of rapid construction, and make up for the shortcomings of existing silicone rubber adhesives.

The application discloses a ketoreductase and application of the ketoreductase in preparation of (R)-4-chloro-3-hydroxybutyric acid ethyl ester. The ketoreductase disclosed by the application has an amino acid sequence shown in SEQ ID NO:1, and a mutant of the ketoreductase has an amino acid sequence shown in SEQ ID NO:3. The ketoreductase and the mutant thereof provided by the application can realize efficient catalysis of a reaction of converting 4-chloroacetyl acetic acid ethyl ester into (R)-4-chloro-3-hydroxybutyric acid ethyl ester.

The application discloses a ketoreductase derived from Schizosaccharomyces japonicus yFS275 and application thereof. The ketoreductase has an amino acid sequence shown in SEQ ID NO:1, and a mutant thereof has an amino acid sequence shown in SEQ ID NO:3. The ketoreductase and the mutant thereof provided by the application can efficiently catalyze the conversion of ethyl 4-chloroacetoacetate into (R)-4-chloro-3-hydroxybutyric acid ethyl ester, and the mutant thereof has higher organic solvent resistance.

The present application relates to the technical field of organic chemical intermediates purification, in particular to a method and device for cis-trans isomerization conversion of 4-halo-2-methoxy imino acetoacetic acid ethyl ester. After cooling, 4-halo-2-methoxy imino acetoacetic acid ethyl ester is mixed with sodium chloride brine to form crystal slurry; then the crystal slurry is discharged into a crystal conversion kettle for aging; after aging, the crystal slurry is heated, extracted and centrifuged, and the organic phase is collected to obtain 4-halo-2-methoxy imino acetoacetic acid ethyl ester. Through the continuous process of "low-temperature brine crystallization enrichment-crystal conversion aging directional conversion-microwave rapid heating to prevent reverse conversion-two-stage extraction centrifugation purification-brine circulation to reduce cost", the content of cis-4-halo-2-methoxy imino acetoacetic acid ethyl ester is stably increased to 92-95%, and the production cost and environmental risk are reduced.

The invention discloses a method for preparing low-acidity ethyl acetoacetate based on continuous separation, and belongs to the field of chemical engineering. According to the method, a part of low-boiling-point acetic acid is removed by controlling the return material ratio and the discharging amount of the ethyl acetoacetate crude product in the rectification process, and then the ethyl acetoacetate finished product is prepared according to the proper return material ratio and the proper discharging amount; and carrying out deacidification treatment on the ethyl acetoacetate finished product through the resin transformed by the alkali liquor to obtain the low-acidity ethyl acetoacetate. The acidity of the low-acidity ethyl acetoacetate prepared by the method is controlled below 0.01%, and the adopted resin is high in adsorption capacity and can be recycled.

The application belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 4,4,4-trifluoroacetyl ethyl acetate. The preparation method of the 4,4,4-trifluoroacetyl ethyl acetate comprises the following steps: first, dissolving a base in an organic solvent, adding trifluoroacetyl chloride under the condition that the temperature is not higher than 0 DEG C, reacting for 0.5-3 h, then adding ethyl acetate, heating to 20-30 DEG C, reacting for 2-6 h, then washing the reaction product with water, drying the organic phase with anhydrous sodium sulfate, and finally evaporating the organic solvent to obtain the 4,4,4-trifluoroacetyl ethyl acetate. The preparation method of the 4,4,4-trifluoroacetyl ethyl acetate is mild in condition, simple in operation, fast in reaction speed, and easy in product separation, and is suitable for industrial production.

The present disclosure provides an engineered ketoreductase polypeptide capable of preparing chiral alcohols, especially for catalyzing the reduction of ethyl 4-chloroacetoacetate to produce ethyl (R)-4-chloro-3-hydroxybutyrate. The polypeptides has high catalytic activity, high stereoselectivity, better thermal stability and solvent tolerance; the reaction process using engineered ketoreductase polypeptides may have a substrate loading of up to 426 g / L and a conversion of up to 99%.

The application discloses a process method for preparing ethyl acetoacetate by crude ester circulation cooling, and belongs to the technical field of chemical industry. The method can dilute the heat generated in the reaction in time and effectively by performing crude ester circulation in the continuous reaction process, better solves the problem of heat accumulation in the reactor, and cannot dissipate heat in time, thereby causing the problem of rapid temperature rise, and avoids the "flying temperature" in the reaction process; the temperature in the reactor is stable without other complex and strict operation control, the operation is simple and feasible; the content of the crude product, the product quality and the yield are improved; the content of the crude methyl acetoacetate obtained by the method is 97.8-98.1%, the content of the finished product after rectification is 99.5-99.7%, and the product yield is 97.8-98.2%; the high-temperature resistance requirement of the pipeline equipment is reduced, and the safety hidden danger is reduced.

The invention relates to the technical field of pesticide synthesis, in particular to a method for synthesizing a saflufenacil intermediate, which comprises the following steps: taking ethyl trifluoroacetoacetate and 2-chloro-4-fluoro-5-aminobenzoate as raw materials, reacting under the action of alkali, and continuously evaporating out low-boiling-point alcohol in the reaction process to obtain an intermediate 1; then adding methylamine hydrochloride turbid liquid into the system, and performing azeotropic dehydration in the reaction process to obtain an intermediate 2; and finally, introducing a phosgene reagent into the system, and carrying out ring closing on the obtained intermediate 2 to obtain a target product. According to the method, cheap and easily available raw materials are used, a uracil ring is directly constructed through a one-pot three-step reaction, and the saflufenacil intermediate is synthesized, so that the process operation is greatly simplified; the target product synthesized by the method has higher yield and purity, the cost is reduced, the solvent can be recycled, the emission of three wastes is reduced, and the subsequent industrial production of saflufenacil is facilitated.

The invention provides an acrylic resin assistant for a cathode electrophoretic coating and a preparation method thereof, and belongs to the technical field of coatings, microgel particles in the acrylic resin assistant for the cathode electrophoretic coating have a shell-core structure, and the microgel particles comprise a hard core component and a soft shell component; the crosslinking monomer comprises at least one of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, zinc diacrylate and zinc dimethacrylate; the functional monomer comprises at least one of diacetone acrylamide, ethyl acetoacetate methacrylate, glycidyl methacrylate and dimethylaminoethyl methacrylate. Under the electric field intensity of 10-100V / cm, the film thickness of the sharp edge part of the prepared nano-emulsion reaches 85 + / -3% of that of a plane area; after curing, the pencil hardness at the edge of the film is greater than or equal to 2H, and the salt spray resistance is greater than or equal to 1200h; and the storage stability of the emulsion is more than 12 months.

The application relates to the field of high polymer materials, and discloses a double-sided protective adhesive tape applied to a loudspeaker diaphragm and capable of resisting cold and hot cycle impact. The double-sided protective adhesive tape is prepared by selecting specific types of acrylate hard monomers and acrylate soft monomers, fully utilizing the fact that the hard monomers with higher Tg have better tensile resistance and heat resistance, the soft monomers with lower Tg have better stretchability and low-temperature resistance, and cooperating with three functional monomers of acetyl ethyl acrylate methacrylate, dimethylaminoethyl methacrylate and maleic anhydride, so as to improve the cohesive strength of the polyacrylate parent adhesive through copolymerization and crosslinking of hydroxyl, amino, anhydride and carbon-carbon double bond, and through the selection of the amount of the curing agent in the pressure-sensitive adhesive and the design of the structure of the double-sided protective adhesive tape, the double-sided protective adhesive tape with good peeling strength, creep resistance and cold and hot cycle impact resistance in a wide temperature range is prepared.

The invention discloses a fully continuous flow chemical synthesis method of an apixaban intermediate (Z)-2-chloro [(4-methoxyphenyl) hydrazono] ethyl acetate. The fully continuous flow chemical synthesis method comprises the following steps: introducing a sodium nitrite solution, a solution of a compound as shown in a formula (I) and acid into a dynamic tubular reactor, and carrying out diazotization reaction under the condition that the temperature is not higher than 0 DEG C; and introducing a sodium acetate solution and an ethyl 2-chloroacetoacetate solution into the microchannel reactor, mixing with the diazotization reaction solution, carrying out a Jappp-Klingemann reaction at-5-2 DEG C, and concentrating to obtain the apixaban intermediate compound shown in the formula (II). The invention provides a full-continuous flow chemical synthesis method of an apixaban intermediate (Z)-2-chloro [(4-methoxyphenyl) hydrazono] ethyl acetate. The target product can be efficiently prepared in dozens of seconds in a high-purity and high-yield manner.

The present application belongs to the technical field of dealcoholized single-component silicone sealant, and specifically discloses a kind of dealcoholized single-component transparent silicone sealant and preparation method, the dealcoholized single-component transparent silicone sealant, according to mass fraction, including alkoxyl end-capped polydimethylsiloxane: 100 parts;Fumed silica filler: 5-30 parts;Surface modifier: 2-10 parts;Crosslinking agent: 10-30 parts;Catalyst: 0.5-2 parts;Adhesion promoter: 0.5-2 parts;Wherein, the surface modifier is diisopropoxy aluminum of diacetyl acetic acid ethyl ester, acetyl acetic acid ethyl ester and vinyl trimethoxysilane are obtained under the condition of 60-80 DEG C for 2-3h and the reflux material of reaction.The dealcoholized single-component transparent silicone sealant prepared by the present application has excellent adhesion to glass, metal, PC, PBT, PET, PVC, ABS and other materials, excellent storage stability and transparency.

The invention relates to a novel process for synthesizing ethyl (R)-(-)-4-cyano-3-hydroxybutyrate, which adopts 3-oxygen-glutaric acid monoethyl ester as a raw material and comprises the following steps of: 1, reacting the 3-oxygen-glutaric acid monoethyl ester as a raw material with a chlorination reagent to generate 4-formyl chloride ethyl acetoacetate; 2, enabling the 4-formyl chloride ethyl acetoacetate to react with an amination reagent to generate 4-formyl amino ethyl acetoacetate; 3, the 4-formamido ethyl acetoacetate and a dehydrating agent are subjected to a reaction, and 4-cyano ethyl acetoacetate is generated; and 4, reacting the 4-cyanoacetoacetic acid ethyl ester with hydrogen under the action of a hydrogenation catalyst to generate (R)-(-)-4-cyano-3-hydroxybutyric acid ethyl ester. According to the method, ethyl 3-oxoglutarate is innovatively adopted as a raw material, and the (R)-4-cyano-3-hydroxybutyrate meeting the quality standard is finally obtained through chlorination, amination, dehydration and chiral hydrogenation reaction. Sodium cyanide is not used as a cyaniding reagent, the amount of three wastes is small, reaction conditions are mild, and the method is suitable for industrial production.

The application discloses a 1, 2, 3-triazole sulfamide derivative, a preparation method and application thereof. The compound has a general formula (A). The synthesis method is as follows: sulfamide is used as a starting material, diazotization, azidation, and then coupling with ethyl acetoacetate to complete the docking of the triazole ring and the sulfamide, and an amide bond is introduced into the structure, and then a series of novel 1, 2, 3-triazole sulfamide derivatives are synthesized. The compounds have excellent bacteriostatic, insecticidal and fungicidal functions on escherichia coli, pseudomonas aeruginosa, salmonella typhi, staphylococcus aureus, bacillus subtilis, and fungi such as candida albicans and aspergillus niger, pests and plant pathogenic bacteria in forestry and other fields.

The invention discloses a synthesis method of an enamine compound and a recycling method of raw materials, and belongs to the technical field of pesticide chemical industry. According to the method, ethyl trifluoroacetoacetate is used as a raw material, substituted phenylacetic acid ammonium is used as an amination reagent, 3-amino-4, 4, 4-ethyl trifluorocrotonate is prepared through a reflux water diversion reaction in a specific organic solvent, and efficient recovery of the amination reagent is achieved through ammonia water mediation. Water generated by reaction is removed in time through reflux water diversion, raw material ester hydrolysis is effectively inhibited, and the yield of enamine is larger than or equal to 98%; and in the recovery process, sublimation is avoided by utilizing the high-boiling-point characteristic of substituted phenylammonium acetate, the problem of condenser blockage is solved, the recovery yield is greater than or equal to 99%, direct application can be realized, the cost is remarkably reduced, and green chemical requirements are met.

The invention relates to the technical field of pesticide preparation, and particularly discloses a novel preparation method of a key intermediate 1-(2, 4, 6-trichlorophenyl)-propyl-2-ketone of a bactericide pydiflumetofen. The method comprises the following steps: by taking 3, 5-dichloro-4-fluoronitrobenzene as a starting raw material, sequentially carrying out four-step unit reactions: reacting with ethyl acetoacetate under an alkaline condition to prepare 2-(2, 6-dichloro-4-nitrophenyl)-3-oxobutyric acid ethyl ester, and reacting with ethyl acetoacetate under an alkaline condition to prepare 2-(2, 6-dichloro-4-nitrophenyl)-3-oxobutyric acid ethyl ester; carrying out degreasing under an acidic condition, so as to obtain 1-(2, 6-dichloro-4-nitrophenyl)-propyl-2-ketone; reducing the nitro group to obtain 1-(4-amino-2, 6-dichlorophenyl)-propyl-2-ketone; and performing Sandmeyer reaction to obtain a target product. The preparation method is novel in synthetic route, few in side reaction and high in total yield, the content of a target product is larger than 99%, the preparation method is suitable for industrial production, and a key support is provided for industrialization of pydiflumetofen.

The application relates to the technical field of antibacterial ceramics, and particularly discloses a visible-light-catalyzed antibacterial ceramic coating and a preparation method thereof. The antibacterial ceramic coating is located on the surface layer of a ceramic glaze, and is formed by spraying an antibacterial sol on the surface layer of the ceramic glaze and then performing heat treatment. The antibacterial sol comprises the following raw materials in mass fraction: 16-35% of tetrabutyl titanate, 20-45% of organic borate, 5-15% of ethyl acetoacetate, 0.5-1% of copper chloride dihydrate, 2-3% of water, 1-2% of hydrochloric acid, 25-35% of anhydrous ethanol and 0-2% of a dispersant. The antibacterial sol can be used for producing the antibacterial ceramic coating, and the coating has the advantages of being firmly coated on the ceramic glaze, having acid and alkali resistance, wear resistance and easy-to-clean property, and having high-efficiency antibacterial performance under visible light.

This invention discloses a continuous method for preparing 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid based on a cascaded process of cyclization-de-alcoholization-scraped membrane fluorination, belonging to the field of continuous synthesis technology in fine chemicals. The method includes: cyclizing ethyl 2-ethoxymethylene-4,4-dichloroacetoacetate with methylhydrazine in a loop reactor with forced external circulation, controlling the circulation ratio boundary at 15:1 to 18:1 to improve the selectivity of the target isomer; continuously removing at least some ethanol from the cyclized liquid and adding sulfolane for solvent replacement, ensuring that the ethanol content in the system before entering the fluorination stage is no higher than 1.0% (wt) and the water content is 0.1-0.2% (wt); subsequently, the resulting intermediate material, along with anhydrous potassium fluoride and 18-crown-6 to form a heterogeneous slurry, is fed into a vertical scraped membrane reactor, with a residence time strictly controlled at 169-171°C for 80-100 seconds, and rapid cooling within 3 seconds after discharge; finally, the target product is obtained through hydrolysis and acidification. This specific combined process can achieve high 1,3-isomer selectivity, high fluorination conversion, low aldehyde byproduct levels, and good long-term continuous operation stability without separating the cyclization intermediate.

The invention belongs to the technical field of sealants, and particularly discloses a sealant capable of being stored stably in a high-temperature environment and a preparation method of the sealant. The sealant is prepared from the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane; 20 to 80 parts of dimethyl silicone oil; 180 to 300 parts of an inorganic filler; 2-8 parts of a molecular sieve catalyst; 1-8 parts of a cross-linking agent; 0.5 to 1.5 parts of a coupling agent; the preparation method of the molecular sieve catalyst comprises the following steps: carrying out hydrothermal crystallization on a mixed solution containing dimethylamine, pseudo-boehmite, phosphoric acid and water, washing, and roasting to obtain a molecular sieve; the preparation method comprises the following steps: adding toluene and titanium diisopropoxy diacetoacetate into a flask in an inert atmosphere, stirring at a material temperature of 25-55 DEG C, adding a molecular sieve, stirring, filtering, and drying in vacuum to obtain the molecular sieve catalyst. The sealant disclosed by the invention has the advantages of excellent performance, high storage stability, no viscosity peak phenomenon in a sealant preparation process and the like.

This invention discloses a method for preparing a coumarin derivative and its application. The coumarin derivative is obtained by Perkin condensation and cyclization reaction of 2,4-dihydroxybenzaldehyde with ethyl acetoacetate to obtain compound (I). Compound (I) then undergoes a nucleophilic substitution reaction with 2,4-dinitrobenzenesulfonyl chloride to obtain the coumarin derivative, the chemical structure of which is shown in formula (II). The coumarin derivative (II) of this invention exhibits significant fluorescence responsiveness and high sensitivity to GSH in 0.2% DMSO-water solution, with a detection limit of 0.49 μM. Furthermore, this compound has low toxicity to H9c2 cells and can be used for the detection of GSH in live cells. This invention provides a simple and highly sensitive coumarin derivative for the detection of GSH, which has broad application prospects.

Disclosed are a method and an apparatus for preparing ethyl (Z)-2-methoxyimino-3-oxobutanoate, which belongs to the technical field of organic synthesis. The method for preparing ethyl (Z)-2-methoxyimino-3-oxobutanoate does not require the use of an acid scavenger and a phase transfer catalyst, and includes: mixing ethyl 2-(hydroxyimino)acetoacetate, methanol, a concentrated aqueous sulfuric acid solution, and a boron trifluoride-methanol complex, and subjecting a resulting mixture to esterification-methylation reaction to obtain the ethyl (Z)-2-methoxyimino-3-oxobutanoate. In the method, dimethyl sulfate is directly generated in a reaction system and further undergoes methylation reaction, without using the acid scavenger and the phase transfer catalyst, with simple operations and lower cost.

This invention discloses a method for preparing benzyl 3-methyl-5-oxopiperidin-1-carboxylic acid ester and its intermediates. The method uses ethyl acetoacetate as a starting material, proceeding through trifluoromethanesulfonation to generate an enol trifluoromethanesulfonate intermediate, palladium-catalyzed cyanation, catalytic hydrogenation, reduction-cyclization transformation under a borohydride / transition metal salt system, nitrogen carbonyl protection, and sulfonium ylide-mediated transformation to obtain the intermediate. The intermediate is further rearranged / cyclized to obtain the target compound. Compared with existing routes, this invention avoids the use of malodorous / high-risk thiol reagents and highly corrosive acids, thus enabling the preparation of the target compound.