73 results about "Sodium ethoxide" patented technology

The invention discloses a hyperbranched water reducing agent for high-tensile wet joint UHPC (Ultra High Performance Concrete) as well as a preparation method and application of the hyperbranched water reducing agent, and belongs to the technical field of concrete admixtures. The preparation method comprises the following steps: mixing pentaerythritol and maleic anhydride, adding a catalyst p-toluenesulfonic acid, and carrying out an esterification reaction to prepare an esterification product; carrying out amidation reaction on the esterification product, diethanol amine and a catalyst sodium ethoxide to obtain a prepolymer; acrylic acid, maleic anhydride and the prepolymer are dissolved in deionized water, an initiator ammonium persulfate is added for a free radical copolymerization reaction, and a main chain polymer is obtained; carrying out phosphorylation reaction on the main chain polymer and phosphorus pentoxide to obtain a phosphorylated main chain polymer; the phosphorylated main chain polymer, methoxypolyethylene glycol and a catalyst p-toluenesulfonic acid are subjected to an etherification reaction, a hyperbranched comb-shaped polymer water reducing agent solution is obtained and then subjected to aftertreatment, and the water reducing agent is prepared. According to the hyperbranched comb-shaped polymer water reducing agent prepared by the preparation method disclosed by the invention, the problems of poor flowability and high viscosity of ultra-high performance concrete (UHPC) are solved by combining a linear side chain of a comb-shaped structure and a three-dimensional branch of hyperbranched topology.

The invention relates to a preparation method of triethylene glycol diacetate, and belongs to the technical field of organic synthesis. The method comprises the following steps: adding triethylene glycol, an acetylation reagent and a multifunctional catalyst into a reaction kettle provided with a stirrer, a thermometer and a reflux condensing tube, and stirring and heating for reaction under the protection of nitrogen; after the reaction is finished, cooling reaction liquid to room temperature, and filtering and recovering the catalyst; performing reduced pressure distillation and silica gel column purification on the filtered reaction liquid to obtain triethylene glycol diacetate; the multifunctional catalyst is prepared from mesoporous silicon dioxide microspheres, 3-mercaptopropyltrimethoxysilane, 4-vinyl benzo-18-crown ether, sodium ethoxide, absolute ethyl alcohol, an ethanol solution of tetrabutyl titanate and chlorosulfonic acid. The preparation method comprises the following steps: preparing the mesoporous silicon dioxide microspheres, 3-mercaptopropyltrimethoxysilane, 4-vinyl benzo-18-crown ether, sodium ethoxide, absolute ethyl alcohol, the ethanol solution of tetrabutyl titanate and chlorosulfonic acid; the triethylene glycol diacetate prepared by the method has high yield and high purity, and can meet industrial production and market requirements.

The invention discloses a preparation method of sodium-mediated lithium sulfide, which specifically comprises the following steps: preparing a sodium ethoxide solution, and dissolving a product obtained after reaction of ethanol and sodium in an organic solvent; adding lithium chloride into the solution for mixing reaction, and centrifuging to obtain a lithium ethoxide solution; introducing hydrogen sulfide gas into the solution, collecting a precipitation product, and calcining to obtain lithium sulfide. The lithium sulfide preparation conditions are mild, the reaction conditions are simple, and the product is easy to collect. The preparation raw materials provided by the invention are metal sodium, ethanol, lithium salt and hydrogen sulfide gas, so that the reaction cost is greatly reduced, commercialization feasibility is realized, and a method for recycling industrial waste gas hydrogen sulfide gas is provided and has certain environmental protection value.

A liquid treatment composition for remediating and removing mercaptans, H2S and other sulfur based contaminants from contaminated hydrocarbon liquids, the treatment composition consisting essentially of a carrier solvent and at least one alkoxide compound. The liquid treatment composition may contain no terpene. Further, the liquid treatment composition may include water. The at least one alkoxide compound includes at least one of sodium methoxide and sodium ethoxide.

The present invention relates to an iron ore reverse flotation inhibitor and a preparation method thereof. In the first step, a mixture of the following components by weight is reacted at 40°C to 50°C for 1 to 6 hours to obtain an auxiliary agent (1): 100 parts of corn starch, mung bean starch, or potato starch, 0.5 to 4.0 parts of sodium hydroxide or sodium ethoxide, 5 to 15 parts of methyl chloroacetate, and 5 to 15 parts of hydroxylamine hydrochloride or hydroxylamine sulfate. In the second step, a mixture of the following components by weight is reacted at 20°C to 50°C for 1 to 3 hours to obtain a finished inhibitor: 100 parts of the auxiliary agent (1) obtained in the first step and 1 to 12 parts of sodium hypochlorite. The inhibitor has strong inhibitory ability, selectivity, and low-temperature adaptability and can be used for room-temperature flotation.

The present invention relates to a method for producing a low-temperature reverse flotation inhibitor for iron ore. The method comprises the following steps: first, reacting a mixture of the following components by weight at 50°C to 60°C for 6h to 8h to obtain an auxiliary agent (1): 100 parts of corn starch and cassava starch, 0.1 to 0.3 parts of hydrogen peroxide, 0.05 to 0.15 parts of ferrous sulfate, and 3 to 5 parts of acrylonitrile; second, reacting a mixture of the following components by weight at 45°C to 55°C for 3 to 4h to obtain an auxiliary agent (2): 100 parts of the auxiliary agent (1) obtained in the first step, 3 to 8 parts of propylene oxide, and 0.1 to 0.8 parts of sodium ethoxide; and third, reacting a mixture of the following components by weight at 40°C to 50°C for 2 to 3h to obtain a finished inhibitor: 100 parts of the auxiliary agent (2) obtained in the second step and 1 to 3 parts of ammonium persulfate. The inhibitor has strong inhibitory ability, selectivity, and low-temperature adaptability and can be used for room-temperature flotation.

The present invention relates to a method for preparing (Z)-3-(2-(5-bromo-1H-indol-3-yl)-2-cyanovinyl)-4-methoxybenzonitrile, which comprises reacting tert-butyl 5-bromo-3-(cyanomethyl)-1H-indole-1-carboxylate, 3-formyl-4-methoxybenzonitrile, and sodium ethoxide solution.

The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of substituted phenylene aromatic diester and application of the substituted phenylene aromatic diester in catalyst preparation. The preparation method comprises the following steps: firstly, enabling 2-hydroxy-3-methyl benzaldehyde to react with m-chloroperoxybenzoic acid and sodium ethoxide to generate 3-methyl catechol; then, triisobutyl aluminum is used as a catalyst, 3-methylcatechol and isobutene are subjected to a reaction, and 5-tert-butyl-3-methylcatechol is generated; finally, the 5-tert-butyl-3-methyl catechol reacts with triethylamine and benzoyl chloride, and the 5-tert-butyl-3-methyl catechol is obtained. According to the novel preparation method of the substituted phenylene aromatic diester, by selecting the specific alkaline reagent and the catalyst, the dependence of a traditional reduction method on a metal reagent is avoided, the yield and the purity of the substituted phenylene aromatic diester are greatly improved, the reaction condition is mild, the cost is low, and the method is suitable for large-scale preparation.

The invention relates to the field of pesticide synthesis, in particular to a synthesis method of ethonicotinic acid. 5-ethyl pyridine-2. 3-dicarboxylic acid diethyl ester and 2-amino-2. 3-dimethyl butyramide are used as raw materials and react in a sodium ethoxide ethanol solution at the temperature of 50-70 DEG C, hydrogen chloride gas is introduced into a system for acidification after the reaction is completed, and imazethapyr and a by-product sodium chloride are obtained. The hydrogen chloride gas is directly introduced in the acidification process, and the acidification process is free of hydration, so that on one hand, no direct wastewater is generated, the generation of wastewater with high salt content and high organic matter content is avoided, the treatment cost is reduced, on the other hand, the byproduct sodium chloride is firstly removed from the system by controlling the ethanol amount of the system, and then concentration and crystallization are performed; the high-purity imazethapyr of which the purity is greater than 99% is obtained by utilizing the solubility of the solvent ethanol to impurities, and the quality of both byproducts and main products is at a higher level in the industry.

The invention discloses a preparation method of 1-amino-2-cyano-1-cyclopentene, which comprises the following steps: 1, preparing a mixed solution, namely mixing a first organic solvent with super alkali in a protective gas atmosphere, heating by adopting a nano infrared energy-saving electric heating coil, stirring, uniformly mixing and dissolving to obtain the mixed solution; the super base is selected from one of potassium tert-butoxide, sodium tert-butoxide, sodium ethoxide, sodium methoxide and sodium hydroxide; 2, cyclization reaction: dropwise adding adiponitrile into the mixed solution, and continuously carrying out infrared heat preservation reaction for 3-8 hours to obtain a reaction solution of 1-amino-2-cyano-1-cyclopentene; 3, cooling crystallization and filtration: cooling the reaction liquid to-10-5 DEG C, standing for crystallization, and carrying out pressure filtration in a protective gas atmosphere to obtain an ACCP crude product and a filtrate; and 4, recrystallizing and refining to obtain a pure product. The method is mild in reaction condition, low in energy consumption, good in product yield and high in product purity, solves the problems of high solvent toxicity, low yield and high environmental protection pressure in the prior art, and is suitable for production of medicine and pesticide intermediates.

This invention relates to a method for preparing a graphene-based coated iron catalyst for the deep removal of trace amounts of acetylene and ethylene impurities from electronic-grade hydrogen chloride, belonging to the field of catalyst technology. The method involves dispersing phenolic resin and graphene quantum dots in toluene, adding allyltrimethylammonium bromide, ferrocene methylamine, and sodium ethoxide, heating and stirring the reaction, and adjusting the pH with acetic acid. Citric acid and ferric acetylacetone are then added, and the mixture is stirred. Sodium borohydride is added in two stages, and the reaction is continued with stirring to obtain a gel precursor. The gel precursor is then ultrasonically dispersed, dried, and subjected to staged heating in a nitrogen-hydrogen atmosphere to obtain the resin-based coated iron catalyst. The catalyst prepared by this invention can effectively remove trace amounts of acetylene and ethylene impurities from electronic-grade hydrogen chloride, improving the purity of electronic-grade hydrogen chloride.

The invention discloses a preparation method of ethyl p-methoxycinnamate, and belongs to the technical field of chemical synthesis. The preparation method of the ethyl p-methoxycinnamate comprises the following steps: mixing ethyl acetate and an ethanol solution of sodium ethoxide, dropwise adding p-methoxybenzaldehyde at 5-10 DEG C, and reacting at 30-50 DEG C to obtain the ethyl p-methoxycinnamate. The yield of the ethyl p-methoxycinnamate prepared by the preparation method provided by the invention can reach 90% or above, and the purity can reach 99.0% or above.

The present invention relates to an antibacterial mefenamic acid silver complex, and its preparation method and application. An antibacterial mefenamic acid silver complex, whose pharmaceutically acceptable compound structure is as follows:. The preparation method of the mefenamic acid silver complex comprises the following steps: first, reacting the ligand mefenamic acid with sodium ethoxide to generate mefenamic acid sodium salt; then, adding the obtained mefenamic acid sodium salt dropwise to a silver nitrate solution; and slowly volatilizing for 3 days to obtain colorless crystals, namely the mefenamic acid silver complex. The mefenamic acid silver complex has an excellent inhibitory effect on common bacteria, and is superior to silver nitrate or mefenamic acid in in vitro tests, and has the potential to replace or supplement existing antibacterial agents on the market. The antibacterial mefenamic acid silver complex or its salt is used as an active component in the preparation of antibacterial agents.

The invention relates to a clean production process for co-producing diacetylmonoxime and acetaldehyde oxime. The method comprises the following steps: adding a modified catalyst, solvent water and butanone into a reaction kettle, starting to stir and heat under the protection of nitrogen, slowly introducing ammonia gas, then slowly adding a hydrogen peroxide aqueous solution, and after the reaction is finished, carrying out centrifugal separation to obtain diacetylmonoxime; the preparation method comprises the following steps: adding hydroxylamine hydrochloride and water into a reaction kettle, stirring to dissolve the hydroxylamine hydrochloride and the water, dropwise adding acetaldehyde under cooling of an ice-water bath, and reacting; dropwise adding alkali liquor, and stirring to obtain an acetaldehyde oxime water solution; the method comprises the following steps: extracting an acetaldoxime aqueous solution with dichloromethane, drying an extract liquid with anhydrous sodium sulfate, fractionating at normal pressure to obtain most of a solvent, fractionating at reduced pressure, and collecting fractions to obtain anhydrous acetaldoxime; the modified catalyst disclosed by the invention is obtained by reacting a TS-1 molecular sieve, mercapto siloxane, (E)-1-allyl potassium trifluoroborate, allyl trimethyl stannane, methylbenzene and sodium ethoxide; the diacetylmonoxime and acetaldehyde oxime prepared by the invention have higher purity.

The application discloses a preparation method of 2-cyano-3-hydroxy-2-buten-(4-trifluoromethyl-phenyl)amide, which comprises the following steps: reacting a compound of formula (II) with acetyl chloride or acetic anhydride under the action of a base; wherein the base comprises sodium ethoxide and / or sodium methoxide. In the application, sodium hydride with a relatively high risk coefficient is replaced by sodium alcoholate, the operation difficulty is reduced, the yield is improved compared with sodium hydride, and the application is more suitable for industrial production.

The application belongs to the technical field of organic synthesis, and particularly relates to a preparation method of substituted phenylene aromatic diester and application thereof in preparation of a catalyst. The preparation method comprises the following steps: first, 2-hydroxy-3-methylbenzaldehyde is reacted with meta-chloro peroxybenzoic acid and sodium ethoxide to generate 3-methyl catechol; then, 3-methyl catechol is reacted with isobutene by taking triisobutyl aluminum as a catalyst to generate 5-tert-butyl-3-methyl catechol; finally, 5-tert-butyl-3-methyl catechol is reacted with triethylamine and benzoyl chloride, and the substituted phenylene aromatic diester is obtained. The application provides a novel preparation method of the substituted phenylene aromatic diester, the dependence on metal reagents in a traditional reduction method is avoided by selecting specific alkaline reagents and catalysts, the yield and purity of the substituted phenylene aromatic diester are greatly improved, the reaction condition is mild, the cost is low, and the method is suitable for large-scale preparation.

This invention provides a method for synthesizing the compound DDAO-Sulfate, belonging to the field of chemical synthesis technology. The method includes the following steps: mixing DDAO and sodium ethoxide with anhydrous dimethylformamide to obtain a mixed solution; adding pyridine sulfur trioxide to the mixed solution and heating and stirring the reaction under light-protected conditions; subsequently concentrating under vacuum to obtain a residue; and purifying the residue by column chromatography using an eluent to obtain the final product. This synthetic method effectively improves the yield while selecting and optimizing the reactants, avoiding the use of easily deteriorated reagents and interference caused by the introduction of irrelevant substances, thus providing an efficient pathway for the preparation of fluorescent detection probes for sulfatase.

The invention relates to a preparation method of a skeleton embedded compact asphalt mixture, and belongs to the technical field of asphalt mixture preparation. Putting the preheated coarse aggregate and fine aggregate into stirring equipment, carrying out dry mixing, then adding the modified asphalt, carrying out wet mixing, finally adding the modified filler, and continuously carrying out wet mixing, so as to obtain an asphalt mixture; loading the asphalt mixture into a test mold, adopting a double-sided static pressure molding process, performing static pressure, cooling and demolding to obtain a skeleton-embedded compact asphalt mixture; the modified filler is prepared from limestone mineral powder, gamma-methacryloxy propyl trimethoxy silane, 8-anilino-1-naphthalene sulfonic acid magnesium salt, absolute ethyl alcohol and sodium perethoxide; the Marshall stability, the low-temperature bending strain and the freeze-thaw splitting strength ratio of the prepared asphalt mixture are remarkably improved, and the asphalt mixture can effectively resist high-temperature rutting, low-temperature cracking and water damage.

This invention relates to the field of organic synthesis technology, specifically a method for synthesizing 2-chloro-4-(1H-pyrazol-3-yl)benzonitrile and its application, comprising the following steps: S1. Compound 1a is added to a first organic solvent under inert gas protection and reacted with vinyl isobutyl ether under the conditions of a catalyst and potassium carbonate to obtain a system containing compound 2a; S2. The pH of the system containing compound 2a obtained in step S1 is adjusted to 2-3, and after reaction, compound 1 is obtained through post-treatment; S3. Compound 1 is added to a second organic solvent, and ethyl formate and sodium ethoxide are added to react and obtain a system containing compound 4a; S4. Acetic acid is added to the system containing compound 4a obtained in step S3 for neutralization, and under inert gas protection, hydrazine hydrate is added dropwise to react and the product is obtained through post-treatment. The synthesis method provided by this invention uses readily available raw materials, has a simple processing procedure, does not require column chromatography, simplifies the operation, and facilitates industrial-scale production.

The invention discloses a preparation method of (S)-(2-oxotetrahydrofuran-3-yl)-carbamate, which is characterized by comprising the following steps: S1, taking L-homoserine and dimethyl carbonate as reaction raw materials, and reacting in a methanol solvent under the action of a concerted catalytic system consisting of sodium ethoxide and zinc acetate to obtain a compound (1); s2, the compound (1) is subjected to a cyclization reaction under the acidic condition, and (S)-(2-oxotetrahydrofuran-3-yl)-carbamate is obtained. The preparation method provided by the invention does not use a large amount of acid-binding agent, has high use efficiency and low catalyst consumption, selects the amino protective agent with low price, reduces the cost and three wastes, and is beneficial to large-scale production.

The invention relates to a preparation method of aldehyde group functionalized halogen-containing helicene, which comprises the following steps: S1, dissolving terephthalaldehyde and p-halobenzyl cyanide in ethanol, adding sodium ethoxide into the solution for reaction, and washing, filtering and drying a reaction product to obtain a solid A; s2, dissolving the solid A in methylbenzene, then adding iodine and epoxypropane for reaction, and washing, filtering and drying a reaction product to obtain a solid B; s3, dissolving the solid B in dichloromethane, adding n-butyllithium into the dichloromethane, sequentially and slowly adding methanol, water and hydrochloric acid after the color of the solution is changed, extracting an organic filtrate after the reaction is completed, carrying out rotary evaporation on the organic filtrate, washing, filtering and drying to obtain aldehyde group functionalized halogen-containing helicene; the invention provides the aldehyde group functionalized halogen-containing helicene and the preparation method thereof, the method is simple to operate, the reaction is simple and convenient, the expansion is flexible, the aldehyde group is successfully introduced into the compound, the reaction steps are reduced, and the experiment complexity is reduced.

The invention discloses a synthesis method for preparing an aryl phosphine-oxazoline ligand, which comprises the following steps: sequentially adding an alkyl alcohol alkali metal compound, a first solvent and a compound B into a reaction container, stirring, continuously adding a compound A, carrying out heat preservation reaction at the reaction temperature of 0-100 DEG C, and synthesizing the aryl phosphine-oxazoline ligand by a one-pot method, the alkyl alcohol alkali metal compound is selected from potassium tert-butoxide, sodium tert-butoxide, lithium tert-butoxide, potassium isopropoxide, sodium isopropoxide, lithium isopropoxide, sodium ethoxide and sodium methoxide; the first solvent is selected from the group consisting of tetrahydrofuran, diethyl ether, 1, 4-dioxane, 2-methyltetrahydrofuran, ethylene glycol dimethyl ether, cyclopentyl methyl ether, methyl tert-butyl ether and isopropyl ether. The method has the advantages of few reaction steps, easily available raw materials, mild reaction conditions, high yield, simple separation and convenient purification.

The invention provides an industrial preparation method of tipiracil hydrochloride, which comprises the following steps: A) reacting 5-chloro-6-chloromethyl uracil and 2-aminopyrrolidine hydrochloride in the presence of a solvent and a sodium ethoxide catalyst to obtain a reaction solution; b) controlling the temperature of the reaction liquid to be 0-10 DEG C, adding an acidic medium, adjusting the pH value of the reaction liquid to be 6.0-8.0, adding ethyl acetate, stirring and filtering; c) adding an acidic medium into the filtrate obtained in the step B) to adjust the pH value to 2.0-6.0, and stirring and filtering at 10-30 DEG C to obtain tipiracil hydrochloride; the acid medium in the step B) and the step C) is independently selected from one or more of hydrochloric acid methanol, hydrochloric acid ethanol and concentrated hydrochloric acid. According to the method disclosed by the invention, the product quality is ensured, impurities are not increased, the product purity is 99.95% or above, the operation is simple, the energy consumption is low, the solvent is low in toxicity, harmless, green and environment-friendly, and the yield can be doubled.

The invention relates to a method for producing butanone oxime with high selectivity. The method comprises the following steps: the raw materials are a catalyst, a solvent, butanone, aqueous ammonia and aqueous hydrogen peroxide solution, and the butanone oxime is obtained through ammoximation reaction, distillation of tert-butyl alcohol, separation of oxime water and distillation of butanone oxime; the catalyst is a boron nickel doped titanium silicate, which is mixed with titanium silicate, mercaptosiloxane and ethanol, filtered and dried to obtain the mercapto titanium silicate; the mercapto titanium silicate, allyl (cyclopentadienyl) nickel and sodium ethoxide are subjected to a temperature reaction; and finally (+)-IPC2B (allyl) borane is added, the reaction is continued and the ethanol is removed by distillation to obtain the butanone oxime; the butanone oxime prepared by the method has high conversion rate and selectivity.

The application belongs to the technical field of diboron compound synthesis, and particularly relates to a synthesis method of 1,3-diboron compound. The method comprises the following steps: taking an olefin compound, pinacol diboron and iodo-methylene boronic acid ester as raw materials, performing an olefin carbon boronation reaction in a reaction system composed of a Cu-based catalyst, sodium ethoxide and a solvent under a protective atmosphere to obtain the 1,3-diboron compound. The application provides a copper-catalyzed olefin boronation strategy, uses iodo-methylene boronic acid ester as an electrophilic reagent, constructs a series of racemic 1,3-diboron compounds through a Cu-catalyzed olefin carbon boronation reaction with an excellent yield, realizes an effective 1,3-diboron compound modular synthesis method, and the reaction has the characteristics of mild reaction condition, wide raw material source, simple reaction process and high yield.

The invention relates to a synthesis process of a polythiol compound containing seven sulfur atoms. The invention discloses a continuous flow-kettle type coupling synthesis method of a hepta-sulfur atom polythiol compound. The process adopts a continuous flow and kettle type combined process. Starting from hydrogen sulfide and epoxy chloropropane, an intermediate 1 is generated by using a continuous flow device; reacting the intermediate 1 reaction liquid and a sodium mercaptoethoxide solution by using a kettle type device to generate an intermediate 2; generating an intermediate 3 from the intermediate 2, an acidic reagent, thiourea and the like by using a kettle type device; and hydrolyzing the intermediate 3 and an alkaline solution by using a kettle type device, acidifying by using an acidic reagent, and extracting by using toluene to obtain the polythiol compound containing seven sulfur atoms. The continuous flow device is used for solving the problems of poor kettle type gas-liquid reaction effect of hydrogen sulfide and epoxy chloropropane, serious reaction heat release and the like, and the purity of the intermediate 1 is more than or equal to 90%; the kettle type device is adopted to complete synthesis of an intermediate 2, an intermediate 3 and a product, so that the device process is simple to operate as far as possible, safe and reliable.

The invention discloses a preparation method of 4, 6-dichloro-5-methoxypyrimidine, and belongs to the technical field of organic synthesis. The method comprises the following steps: by taking dimethyl methoxymalonate as a raw material, generating 2-amino-4, 6-dihydroxy-5-methoxypyrimidine from dimethyl methoxymalonate and guanidine salt under the action of sodium ethoxide; then under the action of tert-butyl nitrite, lithium chloride, salicylic acid and tris (pentafluorophenyl) boron, 4, 6-dihydroxy-5-methoxypyrimidine is generated; finally, under the action of phosphorus oxychloride, 4, 6-dichloro-5-methoxypyrimidine is generated. According to the route, in the first step, a 2-aminopyrimidine product is generated through guanidine salt, in the second step, amino is eliminated through azotization, and the synthesis method of the compound is enriched.

The invention provides a preparation method of electronic-grade high-abundance 11B triethyl borate, and belongs to the technical field of organic synthesis. The method comprises the following steps: mixing sodium ethoxide with an organic solvent to obtain a sodium ethoxide feed liquid; the organic solvent is dichloromethane or acetone, the water content in the organic solvent is less than or equal to 0.001 wt%, and the mass ratio of the organic solvent to the sodium ethoxide is (3.5-5): 1; introducing 11B boron trifluoride into the sodium ethoxide feed liquid at the temperature of 10 DEG C below zero to 5 DEG C below zero, and carrying out esterification reaction to obtain esterification product feed liquid; the < 11 > B abundance of the < 11 > B boron trifluoride is greater than or equal to 99.995%; the esterification product feed liquid is subjected to solid-liquid separation, the obtained liquid material is rectified, the 11B triethyl borate with the abundance larger than or equal to 99.995%, the organic purity larger than or equal to 99.995% and the inorganic purity larger than or equal to 99.9995% can be directly obtained, and the method is easy to operate, low in cost and suitable for large-scale production.

The application discloses a preparation method of (S)-(2-oxotetrahydrofuran-3-yl)-carbamate, characterized in that the method comprises the following steps: S1: taking L-homoserine and dimethyl carbonate as reaction raw materials, and performing reaction in a methanol solvent under the action of a synergistic catalytic system composed of sodium ethoxide and zinc acetate to obtain compound (1); and S2: performing a cyclization reaction on the compound (1) under an acid condition to obtain (S)-(2-oxotetrahydrofuran-3-yl)-carbamate. The preparation method does not use a large amount of an acid-binding agent, uses a catalyst with high efficiency and low dosage, selects an amino protecting agent with low price, reduces costs and three wastes, and is beneficial to scale-up production.

The invention relates to (S)-9-(2, 3-dihydroxy propyl)-N2-acetyl guanine and a synthesis method thereof.The synthesis method comprises the steps that a compound 3 serves as a starting material, an ethanol solution of methyl alcohol and sodium ethoxide is added, a reaction is conducted under the low-temperature condition, acetyl is selectively removed, a glacial acetic acid quenching reaction is conducted, concentration and column chromatography purification are conducted, and the target product (S)-9-(2, 3-dihydroxy propyl)-N2-acetyl guanine is obtained. And 3, 3-dihydroxy propyl)-N2-acetyl guanine is obtained. The invention discloses a novel medical intermediate and designs a feasible synthesis method, the synthesis method can be stably carried out at low temperature through the synergistic effect of all reagents, side reactions are effectively avoided, the purity and stability of the product are ensured, and a foundation is laid for popularization of new drugs.