210 results about "Pentanoic Acids" patented technology

The invention discloses a synthesis method of 2-bromomethyl-5-trifluoromethyl furan, which comprises the following steps: S1, carrying out reaction on acetoacetate and halogenated trifluoroacetone under the action of an alkaline substance and a catalyst to generate a 2-acetyl-5, 5, 5-trifluoro-4-oxovalerate crude product; s2, carrying out a cyclization reaction on the 2-acetyl-5, 5, 5-trifluoro-4-oxovalerate crude product, so as to obtain a 2-methyl-5-(trifluoromethyl) furan-3-formate crude product, and carrying out a cyclization reaction on the 2-acetyl-5, 5, 5-trifluoro-4-oxovalerate crude product to obtain a 2-methyl-5-(trifluoromethyl) furan-3-formate crude product; s3, adding an alkaline substance into the crude product, carrying out hydrolysis, and adding acid to adjust the pH value after the hydrolysis is completed, so as to obtain 2-methyl-5-(trifluoromethyl) furan-3-formic acid; s4, the 2-methyl-5-(trifluoromethyl) furan-3-formic acid is subjected to a heating decarboxylation reaction, and 2-methyl-5-(trifluoromethyl) furan is obtained; and S5, carrying out a bromination reaction on the 2-methyl-5-(trifluoromethyl) furan and a bromination reagent to obtain a final product 2-bromomethyl-5-(trifluoromethyl) furan. The raw materials used in the synthesis method are easy to obtain, use of control chemicals is not involved, and industrialization is easy to achieve.

To provide a composition capable of controlling thermal decomposability of molded articles, and polymers, cured products, and molded articles obtained using this composition, and a method for producing polymethyl methacrylate.SOLUTION: Provided is a composition containing methyl methacrylate, methyl pivalate, and methyl isobutyrate, wherein the concentration of methyl pivalate is more than 0 mass ppm and 50000 mass ppm or less in the composition, and the concentration of methyl isobutyrate is more than 0 mass ppm and 2000 mass ppm or less in the composition. Provided are a polymer, a cured product, and a molded article obtained by employing the composition, and a method for producing polymethyl methacrylate by polymerizing methyl methacrylate in the composition.SELECTED DRAWING: None

The invention discloses a bio-based material composite hose and a preparation method thereof, and belongs to the technical field of aluminum-plastic pipes, the bio-based material composite hose provided by the invention comprises a hose head and a hose body, the hose body is formed by lapping bio-based material composite sheets, the bio-based material composite sheet sequentially comprises an outer polylactic acid film, a bonding layer, an aluminum foil, a bonding layer and an inner polylactic acid film, the outer-layer polylactic acid film or the inner-layer polylactic acid film is prepared from the following components in parts by weight: 70 to 90 parts of polylactic acid, 5 to 20 parts of polyhydroxybutyrate-co-valerate and 10 to 30 parts of long carbon chain terminated hyperbranched polycaprolactone. According to the invention, the modified polylactic acid film with complete biodegradability is used in the composite hose, the modified polylactic acid film can be degraded under the action of microorganisms after the use cycle is ended, the aluminum foil is convenient to recycle, and the biocompatibility of the modified polylactic acid film is more beneficial to the application in food packaging, biological medicine packaging and cosmetic packaging.

The invention belongs to the technical field of separation of drug intermediates, and particularly relates to a method for preparing a high-purity dipropylmalonic acid refined product by adding a polar solvent into a dipropylmalonic acid crude product, heating, pulping for a certain time, cooling, filtering and drying. Decarboxylating the refined dipropylmalonic acid product to obtain high-purity valproic acid; distilling the filtrate to recover the polar solvent to obtain 2-methyl-2-propylmalonic acid, and carrying out decarboxylation on the 2-methyl-2-propylmalonic acid to obtain 2-methylpentanoic acid; 2-methylvaleric acid is used as a perfume additive. According to the method disclosed by the invention, the process impurity 2-methyl-2-propylmalonic acid in dipropylmalonic acid is separated, and the process impurity 2-methylvaleric acid (EP-L) in valproic acid or sodium valproate is precisely separated; the quality of the valproic acid product prepared by the method disclosed by the invention meets the requirements of European Pharmacopoeia EP-11 (2023). According to the invention, the problems of quality control and process evaluation of valproic acid or sodium valproate prepared by a dimethyl malonate method are solved.

The invention relates to a method for preparing a rosuvastatin calcium intermediate, and belongs to the technical field of drug intermediate synthesis. The method comprises the following steps: under the protection of nitrogen, carrying out reflux reaction on raw materials including 4-fluorobenzaldehyde and ethyl 4-methyl-3-oxovalerate under the catalysis of piperidine acetate and a co-catalyst, and carrying out reduced pressure distillation recovery to obtain a compound shown as a formula V; dropwise adding 2-ethyl-2-isothiourea and a compound shown in a formula VI, carrying out cyclization reaction under a non-violent reflux condition, and then adding DDQ in batches for oxidation to obtain a compound shown in a formula IV; oxidizing the compound as shown in the formula IV, and immediately quenching by using saturated NaHCO3 after the reaction is finished to obtain a compound as shown in a formula III; the preparation method comprises the following steps: firstly, treating a compound shown as a formula III by using methylamine, and slowly dropwise adding methylsulfonyl chloride under ice bath temperature control to obtain a compound shown as a formula II; reducing the ester group of the compound shown in the formula II in anhydrous toluene by using DIBAL to obtain an alcohol intermediate; then, selective oxidation is performed to obtain a final product; the method integrally has the advantages of high product yield and purity, few byproducts and low production difficulty.

The disclosure provides methods for synthesis of peracetylgalactosamine-1-pentanoic acid, also called peracetylated D-galactosamine C5 linker or GalNAc C5 linker, using a vegetal source as a starting material, such as vegetal-sourced D-glucosamine or D-glucosamine hydrochloride. Also provided are methods for purifying the peracetylgalactosamine-1-pentanoic acid, or GalNAc C5 linker, thus produced so that the end product comprises fewer impurities.

The present invention discloses a method for alkylating polyester materials in which carbonate or carboxylate participates, and relates to comprehensive utilization of waste resources and cascade utilization of raw materials. The product of the method of the present invention is carboxylate and ethylene carbonate or diol. Taking PET as an example, the method uses multiple types of green ionic liquid catalysts, multiple types of carbonate or carboxylate such as dimethyl carbonate (DMC) or dimethyl malonate as methyl sources, and realizes the directional upgrading of PET to DMT under methanol-free conditions, and then DMC captures the generated ethylene glycol in situ, and forms five-membered cyclic ethylene carbonate through dehydration and cyclization. The present invention can be used for the depolymerization upgrading of waste PET materials, and other aromatic or alkyl carboxylic acid compounds (benzoic acid, p-methylbenzoic acid, 4-formylbenzoic acid, cyclohexanoic acid and n-pentanoic acid), similar polyesters and polycarbonates (polyethylene succinate, polyethylene adipate and polyethylene 2,5-furandicarboxylate) are also suitable for the recovery strategy of the present invention.

The invention provides a preparation method of Fmoc-Lys (Ivdde)-OH, which comprises the following steps: reacting dimedone with isovaleric acid under the action of a condensing agent to generate an intermediate compound, then reacting with N-alpha-tert-butoxycarbonyl-L-lysine under the action of organic alkali to obtain an intermediate, then reacting with acid to obtain an intermediate, and finally, separating and purifying the intermediate to obtain the Fmoc-Lys (Ivdde)-OH. Finally, under the action of inorganic alkali, the Fmoc-Lys (Ivdde)-OH reacts with fluorenylmethoxycarbonyl succinimide, and Fmoc-Lys (Ivdde)-OH is obtained. According to the method provided by the invention, the diketone is taken as a starting raw material, Fmoc-Lys (Ivdde)-OH is synthesized through four steps of reaction including two-step condensation reaction, Boc removal reaction and Fmoc feeding reaction, the process is simplified, the operation is simple, the reaction condition is mild, the industrial production difficulty is reduced, expensive raw materials are not involved, the production cost is favorably controlled, and the obtained product is high in purity and high in yield.

The invention discloses a preparation method of 1, 1, 3, 3-tetramethyl butyl peroxypivalate, and belongs to the technical field of organic compound preparation. The method comprises the following steps: mixing 1, 1, 3, 3-tetramethylbutyl hydroperoxide and pivaloyl chloride, pumping the mixture into a tubular fixed bed reactor filled with a catalyst, controlling the mass space velocity at 0.04-0.1 g.min <-1 > / g and the temperature at 20-35 DEG C to obtain 1, 1, 3, 3-tetramethylbutyl peroxide; the catalyst is a copper-vanadium molybdenum oxygen cluster [Cu (1-iPIM) 4] 3 [VMo12O40] catalyst. According to the present invention, the tubular fixed bed reactor is adopted to prepare the 1, 1, 3, 3-tetramethyl butyl peroxypivalate, and the flow rate and the material retention time can be accurately controlled to increase the utilization rate and the stability of the catalyst so as to achieve the continuous production of the 1, 1, 3, 3-tetramethyl butyl peroxypivalate.

The invention relates to N-fluorenylmethoxycarbonyl-L-2-amino-5-phenylpentanoic acid or a pharmaceutical composition and application thereof, and relates to the technical field of biological medicines. According to the application disclosed by the invention, the N-fluorenylmethoxycarbonyl-L-2-amino-5-phenylpentanoic acid is found to have the effects of reducing total cholesterol, triglyceride and low-density lipoprotein cholesterol in serum and increasing high-density lipoprotein cholesterol in serum for the first time; the compound can be used for preparing a medicine for reducing total cholesterol in serum, a medicine for reducing triglyceride in serum, a medicine for reducing low-density lipoprotein cholesterol in serum and a medicine for increasing high-density lipoprotein cholesterol in serum, and can be used for preparing medicines for reducing total cholesterol in serum, triglyceride in serum, low-density lipoprotein cholesterol in serum and high-density lipoprotein cholesterol in serum. And an effective new means and a new way are provided for preparing the medicine for preventing or treating the hyperlipemia.

The present invention relates to polymorphs of the hydrochloride salt of 5-{2-[({8-[(2,6-dimethylbenzyl)amino]-2,3-dimethylimidazo[1,2-a]pyridine-6-yl}carbonyl)-amino]ethoxy}-5-oxopentanoic acid (linaprazan glurate), more specifically Form 1 and Form 2 of the HCl salt of linaprazan glurate. The invention also relates to a process for the preparation of such polymorphs, to pharmaceutical compositions comprising such polymorphs, and to the use of these polymorphs in the treatment or prevention of gastrointestinal inflammatory diseases or gastric acid related diseases, in particular erosive gastroesophageal reflux disease (eGERD).

The invention discloses a generalized pustular psoriasis diagnosis marker based on metabonomics and application of the generalized pustular psoriasis diagnosis marker. The diagnostic marker is prepared from one or more of the following 35 compounds: pyruvic acid, alpha-ketoisovaleric acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, methane thiophosphoric acid, proline, uracil, tranexamic acid, 4-aminobutyric acid, threonine, scopoletin, dodecanol, N-methyl-L-leucine, L-cysteine-glycine and L-kynurenine. The feed additive is prepared from the following raw materials: 3-hydroxybenzoic acid, allantoin, delta-tocopherol, xylofuranose, glucose-1-phosphoric acid, pyrophosphate, taurine, L-asparagine, phthalic acid, 4-(dimethylamino) azobenzene, 5-tert-butyl-1h-indole-2, 3-dione, quinic acid, glucose, histidine, lysine, palmitic acid, 7-methylguanine, oleic acid and whale acid. The marker can be used for accurately distinguishing patients with generalized pustular psoriasis from healthy people.

The application relates to a preparation method of a crosslinked polymer and belongs to the technical field of polymer preparation. The preparation method of the crosslinked polymer provided by the application comprises the following steps: (1) mixing reactant A and reactant B to perform an esterification reaction to obtain an esterification product; (2) dissolving a crosslinking agent in the obtained esterification product and standing for solidification, so that the crosslinked polymer is obtained; the reactant A is a polyether polyol containing at least three hydroxyl groups; the reactant B is 4-(cyclopenta-2,4-dien-1-ylidene) pentanoic acid; and the crosslinking agent contains a maleimide group. The application constructs a fulvene-maleimide D-A reaction system capable of being rapidly crosslinked under low-temperature conditions by end-capping fulvene at the end of a polyether polyol and then adding a crosslinking agent with a maleimide group.

The disclosure relates to oral care compositions comprising guanidine in free or orally acceptable salt form, a cationic quaternary ammonium compound (e.g., a pyridinium compound) (e.g., cetyl pyridinium chloride (CPC)), a fluoride source, and optionally a zinc source (e.g., zinc lactate or zinc citrate and zinc oxide) as well as to methods of using and of making these compositions. 20 25 20 43 72 12 J un 2 02 5 2 0 2 5 2 0 4 3 7 2 1 2 J u n 2 0 2 5 A B S T R A C T T h e d i s c l o s u r e r e l a t e s t o o r a l c a r e c o m p o s i t i o n s c o m p r i s i n g g u a n i d i n e i n f r e e o r o r a l l y a c c e p t a b l e s a l t f o r m , a c a t i o n i c q u a t e r n a r y a m m o n i u m c o m p o u n d ( e . g . , a p y r i d i n i u m c o m p o u n d ) ( e . g . , c e t y l p y r i d i n i u m c h l o r i d e ( C P C ) ) , a f l u o r i d e s o u r c e , a n d o p t i o n a l l y a z i n c s o u r c e ( e . g . , z i n c l a c t a t e o r z i n c c i t r a t e a n d z i n c o x i d e ) a s w e l l a s t o m e t h o d s o f u s i n g a n d o f m a k i n g t h e s e c o m p o s i t i o n s . 2 0 2 5 2 0 4 3 7 2 1 2 J u n 2 0 2 5

The invention belongs to the technical field of medicine synthesis, and particularly relates to a method for efficiently preparing cyclobutane derivatives. Comprising the following steps: dissolving 4-chloro-7H-pyrrolo [2, 3-d] pyrimidine and chloromethyl pivalate in 1, 4-dioxane, and adding an acid binding agent for reaction to obtain a reaction solution; the preparation method comprises the following steps: adding 1-(1-ethoxyethyl)-4-pyrazol boronic acid pinacol ester, purified water, a catalyst and an acid-binding agent into a reaction kettle, carrying out Suzuki reaction, separating liquid, adding activated carbon into an upper organic phase for decoloration, adding an organic solution containing hydrogen chloride for crystallization, and filtering to obtain a wet product; and dissolving the wet product and 2-[1-(ethylsulfonyl)-3-azacyclobutane] acetonitrile in 1, 4-dioxane, and reacting under an alkaline condition to obtain the cyclobutane derivative. According to the preparation method, synthesis is performed through a one-pot four-step reaction, a solvent only relates to 1, 4-dioxane and water, and post-treatment is simple, convenient and efficient.

The invention discloses a method for preparing halogenated fluorine-containing olefin with high yield as well as a product and application of the halogenated fluorine-containing olefin, dihalogenated perfluoroethane (ICF2CF2I or BrCF2CF2Br) and ethylene are taken as raw materials, under the action of a peroxide initiator TAPP (tert-amyl peroxypivalate, the addition amount of which is 0.2%-0.3% of the weight of the perfluorinated halogenated ethane), the ethylene is continuously introduced to maintain the reaction pressure of 0-5 kg, and the halogenated fluorine-containing olefin with high yield is prepared. Carrying out addition reaction to generate a dihalogenated fluorine-containing alkane intermediate; and heating toluene and sodium hydroxide / potassium hydroxide to 60-80 DEG C in a three-neck flask, superposing the intermediate to carry out elimination reaction, and continuously collecting the generated olefin through a distillation head to finally obtain ICF2CF2CH = CH2 or BrCF2CF2CH = CH2. The method is strong in process controllability, high in ethylene utilization rate and high in product separation efficiency, and adapts to iodination and bromination double-system production.

The present invention relates to a pharmaceutical composition for oral administration, the pharmaceutical composition comprising: a) immediate-release granules comprising i. an active ingredient selected from the group consisting of valproic acid, semi-sodium valproic acid, sodium valproic acid, and magnesium valproic acid, and ii. a filler; and b) sustained-release pellets comprising: i. a pellet core comprising (1) an active ingredient selected from the group consisting of valproic acid, semi-sodium valproic acid, sodium valproic acid, and magnesium valproic acid, and (2) a filler; and ii. on the pellet core iii. A sustained-release pellet comprising a subcoat provided on the subcoat, the content of which is 10 to 20% by weight based on the weight of the pellet core and contains a film-forming agent, and iii. a sustained-release coating provided on the subcoat, the content of which is 25 to 100% by weight based on the weight of the pellet core coated with the subcoat and contains a film-forming agent, wherein the amount of active ingredient in the immediate-release granules accounts for 70 to 80% by weight of the total weight of active ingredients in the pharmaceutical composition, and the amount of active ingredient in the sustained-release pellets accounts for 20 to 30% by weight of the total weight of active ingredients in the pharmaceutical composition. In yet another aspect, the present invention relates to a method for producing a pharmaceutical composition and a pharmaceutical composition for use in a method of pretreatment of cancer.

The application discloses a kind of process methods for optimizing control production 5-aminovaleric acid, step one, amino acid fermentation seed is inoculated in culture medium, and aerobic fermentation culture is carried out;During fermentation culture process, fermentation temperature is controlled at 30-35 DEG C, pH value is maintained at 6.5-7.5, and by controlling aeration and stirring, dissolved oxygen level is controlled at 20%-30%;After fermentation, fermentation broth is separated, and 5-aminovaleric acid crude product is obtained;5-aminovaleric acid crude product is sequentially subjected to decolorization, crystallization and refining, and finally 5-aminovaleric acid finished product is obtained.The application uses optimized fermentation conditions, by accurately controlling fermentation temperature, pH value and dissolved oxygen level, to ensure the stability and efficiency of fermentation process, improve product quality and yield.

The invention discloses a high-efficiency transfer hydrogenation method of non-activated olefin, which comprises the following steps: adding a non-activated alkenyl amide compound, nickel acetylacetonate dihydrate, phenylsilane, water and cesium pivalate into an organic solvent 1, 4-dioxane, reacting at room temperature under a nitrogen condition for 12 hours, and after the reaction is completed, filtering to obtain a filtrate, namely the high-efficiency transfer hydrogenation method of the non-activated olefin. And performing post-treatment (extraction and column chromatography separation) to obtain the corresponding alkyl chloride compound. According to the method, phenylsilane and water are directly used as hydrogen sources, direct use of hydrogen can be avoided, operation is easy and convenient, and efficient construction of C (sp3)-C (sp3) bonds can be achieved through transfer hydrogenation of non-activated olefin. The conversion reaction conditions are extremely mild, and the reaction activity is high; the method has the advantages of excellent atom economy and step economy, wide substrate application range, good functional group compatibility and the like. It is worthy that the synthesis method is also suitable for later-stage modification of medicine molecules, and the druggability of the molecules is expected to be further improved.

The invention belongs to the field of pharmaceutical chemical engineering and fine chemical engineering, and relates to a method for recovering 2-cyano-2-methylvaleric acid as shown in a chemical structural formula I. The method comprises the following steps: selecting methyl 2-cyanoacetate and 1-chloropropane, and carrying out catalytic dipropylation under the action of potassium carbonate to prepare methyl 2-cyano-2-valproate; hydrolyzing the latter to obtain 2-cyano-2-valproic acid (crude product) as shown in a formula III; adding water, alcohol and other polar solvents into the 2-cyano-2-valproic acid crude product, pulping, carrying out gradient crystallization, filtering, and carrying out low-temperature vacuum drying to obtain 2-cyano-2-valproic acid monohydrate and 2-cyano-2-methylvalproic acid monohydrate; the 2-cyano-2-valproic acid monohydrate is subjected to high-temperature decarboxylation hydrolysis through sulfuric acid, and valproic acid is prepared; and carrying out high-temperature decarboxylation hydrolysis on the 2-cyano-2-methylpentanoic acid monohydrate by using sulfuric acid to obtain the essence 2-methylpentanoic acid.

To provide a stable crystalline form of linaprazan glurate.SOLUTION: Provided are polymorphs of the hydrochloride salt of 5-{2-[({8-[(2,6-dimethylbenzyl)amino]-2,3-dimethylimidazo[1,2-a]pyridine-6-yl}carbonyl)amino]ethoxy}-5-oxopentanoic acid (linaprazan glurate).SELECTED DRAWING: None

The invention provides a preparation method of pivalate, which comprises the following steps: carrying out condensation reaction by using isobutanol, formic acid and concentrated sulfuric acid as raw materials, carrying out alcoholysis by using fatty alcohol, extracting and layering after the reaction is finished, and desolventizing an organic phase to obtain a crude pivalate product. According to the preparation method of the pivalate, isobutanol and formic acid which are low in price are adopted as raw materials, the production cost is low, the pivalate is synthesized through a one-pot method, the process is simple, the reaction temperature is low, the conditions are milder, and the requirements of industrial production can be met.

The invention belongs to the technical field of organic synthetic chemistry, and discloses a method for efficiently synthesizing methyl 2-chloro-3-oxovalerate. According to the method, high-selectivity chlorination is performed on a beta-site C-H bond of methyl 3-oxovalerate under a mild condition by taking sodium chloride as a chlorine source and adopting a dual-catalysis system consisting of engineered halogenase and a visible light-sensitive catalyst under visible light irradiation. The engineered halogenase is a HalB triple mutant, and the affinity and regioselectivity of a substrate are remarkably improved; the photosensitive catalyst is a ruthenium bipyridine complex and synergistically drives generation of chlorine free radicals. According to the invention, a brand new biological-photochemical synergistic catalysis platform is constructed by organically combining the substrate recognition capability of the engineered halogenase and an electron transfer mechanism driven by visible light catalysis, so that the contradiction among selectivity, mildness and atomic efficiency of a traditional chlorination method is solved; and the method can be expanded to precise synthesis of other beta-functionalized ketone ester compounds.

The invention discloses a generalized pustular psoriasis diagnosis marker based on metabonomics and application of the generalized pustular psoriasis diagnosis marker. The diagnostic marker is prepared from one or more of the following 35 compounds: pyruvic acid, alpha-ketoisovaleric acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, methane thiophosphoric acid, proline, uracil, tranexamic acid, 4-aminobutyric acid, threonine, scopoletin, dodecanol, N-methyl-L-leucine, L-cysteine-glycine and L-kynurenine. The feed additive is prepared from the following raw materials: 3-hydroxybenzoic acid, allantoin, delta-tocopherol, xylofuranose, glucose-1-phosphoric acid, pyrophosphate, taurine, L-asparagine, phthalic acid, 4-(dimethylamino) azobenzene, 5-tert-butyl-1h-indole-2, 3-dione, quinic acid, glucose, histidine, lysine, palmitic acid, 7-methylguanine, oleic acid and whale acid. The marker can be used for accurately distinguishing patients with generalized pustular psoriasis from healthy people.

The invention belongs to the technical field of functional fibers, and particularly relates to a preparation method of skin-care and odor-removing regenerated cellulose fibers. According to the preparation method, a modified functional agent is obtained by generating a polytannic acid thin layer on the surface of a bamboo charcoal adsorbate, so that the dispersity of bamboo charcoal powder particles and the slow release effect on jojoba oil are improved; polytannic acid on the surface of the modifying functional agent and amino in amino modified dimethyl siloxane are subjected to a Michael addition / Schiff base reaction under the weak alkaline condition to form a cross-linked structure, the internal stability of the fiber is improved, meanwhile, the fiber strength and the combination effect of the modifying functional agent and the fiber are improved, and the function durability is higher. The prepared skin-care odor-removing regenerated cellulose fiber has excellent mechanical properties and a good deodorizing effect, the reduction rate of ammonia gas is greater than or equal to 90%, the reduction rate of acetic acid is greater than or equal to 90%, and the reduction rate of isovaleric acid is greater than or equal to 85%.

The present application relates to the preparation method of magnesium valproate shown in chemical structural formula I: under the action of potassium carbonate and PTC, dimethyl malonate is subjected to dipropylization with 1-chloropropane in DMF solvent to prepare dimethyl dipropyl malonate shown in formula III; III is subjected to hydrolysis reaction to prepare dipropyl malonic acid shown in formula II; II is uniformly mixed with magnesium oxide, and heated to prepare magnesium valproate shown in formula I by decarboxylation, and the total yield of magnesium valproate is not less than 90.0%; the preparation reaction is as follows: wherein, the PTC for dipropylization is selected from quaternary ammonium salt, the reaction temperature is 50-140 DEG C, the reaction time is 4.0-14.0 h; the hydrolysis temperature is 70-95 DEG C, the time is 2.0-4.0 h; the decarboxylation temperature is 140-158 DEG C, and the time is 3.0-5.0 h.

The invention belongs to the technical field of compounds, and provides a preparation method of R-3-hydroxypentyl-4-tenoic acid tert-butyl ester. The preparation method comprises the following steps: firstly, mixing tert-butyl 5-chloro-3-oxo-4-valerate, a first alkaline substance, a specific catalyst and a solvent, carrying out asymmetric hydrogenation reaction, and then sequentially carrying out substitution reaction, elimination reaction and deprotection reaction to prepare R-3-hydroxypent-4-olefine acid tert-butyl ester, so that the chiral purity of the product is high. The catalyst is easy to separate and recycle and can be reused, materials are saved, and production cost is reduced. Moreover, the preparation method provided by the invention improves the yield of R-3-hydroxypentyl-4-tenoic acid tert-butyl ester, has the advantages of low requirements on equipment, easily available raw materials, easy product separation, simple and easy reaction operation, environmental friendliness, green and safe synthesis process, stability and low production cost, and is suitable for large-scale industrial production.

The invention belongs to the technical field of medicine detection, and particularly relates to a high performance liquid chromatography detection method for dipropylmalonic acid and impurities thereof. The method comprises the following steps: preparing a to-be-detected sample into a test solution; the to-be-detected sample is dipropyl malonic acid prepared by adopting a diethyl malonate method and impurities of the dipropyl malonic acid; and detecting the test solution by adopting a high performance liquid chromatography method to obtain a detection result of dipropylmalonic acid and impurities thereof in the sample to be detected. According to the detection method provided by the invention, the detection of dipropylmalonic acid prepared by adopting a diethyl malonate method and impurities thereof is realized through high performance liquid chromatography (HPLC) for the first time, and the problems of quality control and process evaluation of the dipropylmalonic acid prepared by adopting the diethyl malonate method, which is an intermediate of a sodium valproate raw material medicine, are solved; therefore, detection and control of impurities (including 2-ethyl valeric acid) in the sodium valproate raw material medicine are realized.