60 results about "Methyl carbamate" patented technology

The invention discloses an anti-yellowing PVB (Polyvinyl Butyral) adhesive for laminated glass and a preparation method thereof, and relates to the technical field of adhesives. The yellowing-resistant PVB glue for the laminated glass has the advantages that the yellowing resistance is high; the modified PVB / nano silicon dioxide composite material is prepared from the following raw materials in parts by weight: 55 to 65 parts of modified PVB resin, 4 to 6 parts of modified nano silicon dioxide, 15 to 20 parts of dioctyl adipate, 0.5 to 1 part of a compound antioxidant, 0.3 to 0.8 part of an ultraviolet absorbent UV-327, 0.2 to 0.5 part of a silane coupling agent KH-560, 0.3 to 0.6 part of ethylene bis stearamide, 0.1 to 0.3 part of 2-benzimidazole methyl carbamate, 3 to 5 parts of tris (1-chloro-2-propyl) phosphate and 0.1 to 0.3 part of nano titanium dioxide. 5 to 8 parts of isopropanol; 0.8 to 1.2 parts of polycarbodiimide. The special modified PVB resin and the nano silicon dioxide are matched with the auxiliary agents such as the compound antioxidant, the anti-yellowing performance of the PVB glue for the laminated glass is remarkably improved through precise process preparation, the components have a synergistic effect, the process is controllable, the product performance is stable, and the cohesiveness is good.

The invention relates to the technical field of waste asphalt regeneration, and particularly discloses a waste asphalt regenerant, large-proportion waste asphalt containing the waste asphalt regenerant and a preparation method of the waste asphalt regenerant and the large-proportion waste asphalt. The waste asphalt regenerant is prepared from the following raw materials: 45 to 55 percent of epoxidized illegal cooking oil, 15 to 20 percent of furfural refined oil, 8 to 12 percent of methyl carbamate, 3 to 5 percent of nano mica powder, 10 to 15 percent of desulfurized rubber powder and 5 to 8 percent of SEBS (Styrene-Ethylene-Butylene-Styrene) modifier. The waste asphalt regenerant has a three-dimensional network structure which is subjected to polar bonding; the large-proportion waste asphalt is prepared from the following components in parts by mass: 70 to 90 parts of waste asphalt, 15 to 25 parts of limestone sand, 10.5 to 18 parts of waste asphalt regenerant, 1 to 5 parts of new asphalt and 0.05 to 0.15 part of long-chain aliphatic hydrocarbon warm mixing agent. The regenerant can act in molecules of the waste asphalt, a stable space structure with elasticity and a three-dimensional network is formed through the synergistic effect of multiple components, and good low-temperature crack resistance and performance stability are kept after the waste asphalt is regenerated through the chemical bond effect among the components.

The invention relates to a kettle residue recovery process of methyl carbamate, and belongs to the technical field of chemical engineering, the kettle residue recovery process of methyl carbamate comprises the following steps: adding the kettle residue of methyl carbamate into water, stirring for dissolving, adding chloroform, extracting, standing for layering, taking an oil phase dissolved with methyl carbamate at the lower layer, cooling to room temperature, filtering, washing, and drying to obtain the methyl carbamate. Drying to constant weight to obtain recycled methyl carbamate; and adjusting the pH value of an upper water phase composed of impurities such as urea, biuret and triuret to 7.5-8 by using a pH regulator, introducing into a sealed reaction tank filled with a modified mesoporous molecular sieve, adsorbing at normal temperature and normal pressure, filtering, and treating the filtrate at 60-80 DEG C to obtain the recycled and treated urea. The whole preparation process is simple and controllable, and the methyl carbamate and the urea in the kettle residues of the methyl carbamate are recycled.

The invention provides an ionic liquid catalyst and a preparation method thereof, methyl methyl carbamate and a preparation method, a preparation system and application thereof. The structural formula of the ionic liquid catalyst is [Zn (CH3NHC (O) OCH3) 2] < 2 + >. 2 (CH2COO)-. According to the invention, urea, methanol and dimethyl carbonate are used as raw materials, and methyl carbamate is prepared under the catalytic action of the ionic liquid catalyst. Methanol, dimethyl carbonate and urea are subjected to multi-step alcoholysis reaction and ammonolysis reaction, the target product selectivity is high, the raw material conversion rate is high, the methyl methyl carbamate product purity is high, no organic tin residues exist, and the catalyst cost is low.

The invention belongs to the technical field of pharmaceutical analysis, and discloses a method for determining two potential genotoxic impurities in carbon [13C]-urea by gas chromatography. Comprising the following steps: (1) preparing a sample solution; (2) preparing a reference solution; (3) taking nitrogen as carrier gas, and detecting by adopting a medium-polarity or weak-polarity chromatographic column separation system; and (4) calculating by a peak area through an external standard method to obtain the accurate contents of methyl carbamate and ethyl carbamate in the carbon [13C]-urea. The method disclosed by the invention is simple to operate, good in specificity, linearity, precision and accuracy and high in sensitivity, and can realize accurate detection of residual potential genotoxic impurities, namely methyl carbamate and ethyl carbamate, in the carbon [13C]-urea.

The invention belongs to the field of organic synthesis, and particularly provides an integrated synthesis method of chlorocarbonyl [4-(trifluoromethoxy) phenyl] methyl carbamate, which comprises the following steps: dropwise adding methyl chloroformate, slowly dropwise adding a NaOH solution, separating liquid, adding the NaOH solution again, azeotropic with water, and realizing integrated synthesis, thereby obtaining the chlorocarbonyl [4-(trifluoromethoxy) phenyl] methyl carbamate. The intermediate [4-(trifluoromethoxy) phenyl] methyl carbamate can be directly used for preparing sodium salt in the next step without discharging, drying and other operations in the synthesis process, and moisture absorption sensitive substances such as sodium hydride, potassium tert-butoxide, sodium methoxide and the like do not need to be used, so that the safety and stability of the synthesis process are improved.

The invention provides a method for detecting ethyl chloroformate, 1,3-bromochloropropane and ethyl methylcarbamate impurities in an eptazocine intermediate (-)-(1S-6S)-2,3,4,5,6,7-hexahydro-1,4-dimethyl-1,6-methylene-1hydro-4-phenylin-10-methoxy ether (compound 2). The method is rapid, accurate and has a low detection limit. The method can effectively control the content of ethyl chloroformate, 1,3-bromochloropropane and ethyl methylcarbamate that may remain in compound 2, thereby ensuring the safety of the use of an eptazocine hydrobromide preparation product further prepared from an eptazocine hydrobromide raw material.

The invention discloses a heterogeneous catalyst for synthesizing methyl phenylcarbamate as well as a preparation method and application of the heterogeneous catalyst, and belongs to the technical field of heterogeneous catalysts and synthesis of methyl phenylcarbamate. The heterogeneous catalyst for synthesizing the methyl phenylcarbamate comprises a carrier and an active component, wherein the mass percentage content of the carrier in the heterogeneous catalyst for synthesizing the methyl phenylcarbamate is 90.0%-99.9%, and the mass percentage content of the active component in the heterogeneous catalyst for synthesizing the methyl phenylcarbamate is 0.1%-10.0%; the carrier is carbon, and the active component is zinc and / or bismuth; the preparation method comprises the steps of resin modification and active component loading. The heterogeneous catalyst for synthesizing the methyl phenylcarbamate is applied to preparation of the methyl phenylcarbamate, dimethyl carbonate and aniline are mixed and react at the temperature of 80-180 DEG C for a specified time, and then the product methyl phenylcarbamate is obtained through the reaction; the catalytic system in the process is high in reaction activity and good in stability, and has a good industrial application prospect.

The invention discloses a flotation collecting agent and a preparation method and application thereof, and relates to the technical field of mineral separation. The flotation collecting agent comprises carbonized methyl carbamate, zinc diethyldithiocarbamate, butyl octanol and sulfate according to the mass ratio of (3-6): (1-12): (2-3): (3-8). According to the prepared composite flotation reagent, in the cassiterite ore flotation treatment process, after one-time roughing, three-time scavenging and three-time concentration, the loss of easily-argillized fine-grain and micro-fine-grain cassiterite in tailings is reduced, the cassiterite content in cassiterite ore is reduced through precise adsorption of the reagent, efficient recovery of the fine-grain and micro-fine-grain cassiterite is achieved, and the cassiterite flotation efficiency is improved. The effective recovery of cassiterite is improved, and the tin grade and the recovery rate in the tin concentrate are also remarkably improved.

The present invention relates to a method for preparing methyl pentanediamine carbamate using furfurylamine as a raw material. This method uses furfurylamine, a downstream product of the biomass-based platform molecule furfural, as a raw material. Through the hydrodeamination amination of methyl 2-furfurylmethylcarbamate, N-(5-aminopentyl)carbamic acid methyl ester is prepared, and finally methyl pentanediamine carbamate is synthesized. The present invention provides a new process route for synthesizing methyl pentanediamine carbamate, solves the problem of serious pollution in the production process of PDI, meets the development requirements of green chemistry, and has broad industrial prospects.

The invention relates to the technical field of preparation of functional water-based asphalt coatings, in particular to a water-based asphalt anti-insect and anti-corrosion coating and a processing technology thereof. The invention relates to a water-based asphalt anti-insect and anti-corrosion coating which consists of a water-based asphalt basic coating and water-based anti-insect polymer latex, the water-based insect pest prevention polymer latex comprises deionized water, an emulsifier, polymer latex particles and insect pest prevention filler; the insect pest prevention filler comprises a porous inorganic filler carrier and an insect pest prevention agent loaded on the porous inorganic filler carrier, and the porous inorganic filler is one of zeolite, halloysite and porous silicon dioxide; the insect pest prevention agent is at least one of 4-nitrophenyl carbamate, (3-methyl azetidin-3-yl) methyl tert-butyl carbamate, malathion monocarboxylic acid, a folium artemisiae argyi extract, an azadirachta indica extract, a fresh ginger extract, a cinnamomum camphora leaf extract and a fresh ginger extract. The anti-corrosion and anti-rust paint can play an effective anti-corrosion and anti-rust effect and also has an excellent and lasting effect of preventing plant diseases and insect pests.

The invention relates to a process for synthesizing toluene diisocynate by a low-energy-consumption non-phosgene method, which comprises the following steps: reacting toluenediamine with dimethyl carbonate to synthesize toluene dicarbamate, and then decomposing the toluene dicarbamate to prepare the toluene diisocynate. According to the process, heat of a reaction product for synthesizing methyl toluenediamine and dimethyl carbonate is utilized, and part of light components are evaporated out through flash evaporation operation; and then adding a solvent for the decomposition reaction of toluene dicarbamate into the flashed material, continuously evaporating components such as dimethyl carbonate and the like, and enabling toluene dicarbamate and the solvent to enter a decomposition refining reaction tower together for reaction and separation to obtain a product. Compared with the prior art, the method has the advantages that the process is simple, the energy consumption, the equipment and the operation cost are saved, the purity of the obtained product and byproduct is high, and the total production cost of the toluene diisocyanate is greatly reduced.

This invention discloses a method for synthesizing methyl amino-methyl-phenylcarbamate compounds from p-toluidine. The method uses p-toluidine as a raw material, employs anhydrous zinc acetate catalyst and the green solvent dimethyl carbonate, to first prepare methyl p-toluylcarbamate, followed by one-step direct amination to prepare methyl 2-amino-4-methylphenylcarbamate and methyl 3-amino-4-methylphenylcarbamate. This invention has advantages such as readily available raw materials, an environmentally friendly reaction process, high atom utilization, and a first-step reaction yield of up to 96% and a second-step reaction yield of up to 35.7%.

The present invention relates to the technical field of asphalt regeneration, and in particular to an asphalt regeneration agent and a preparation method thereof, wherein the asphalt regeneration agent is composed of the following raw materials: 45-55 parts of purified waste oil, 10-15 parts of furfural emulsified oil, 10-15 parts of methyl carbamate, 10-15 parts of waste rubber powder, 3-6 parts of mica powder, and 2-4 parts of modified fiber. The present invention firstly uses waste oil as the main preparation raw material to achieve the reuse of waste resources and effectively reduce costs; secondly, the original system of aged asphalt is broken through the emulsification effect of furfural emulsified oil and the polar effect of methyl carbamate, so that components such as waste oil, furfural extracted oil, and mica powder are redissolved, and the proportion of each component is rebalanced, while improving the stability and strength of the regenerated asphalt.

The present invention discloses a flotation collector, a preparation method, and an application thereof, and relates to the field of mineral processing technology. The flotation collector comprises carbonized methyl carbamate, zinc diethyldithiocarbamate, butyl octanol, and sulfate in a mass ratio of (3-6): (1-12): (2-3): (3-8). During the flotation treatment of cassiterite ore, the composite flotation agent prepared thereby reduces the loss of easily muddied fine and micro-grained cassiterite in tailings after one roughing, three scavenging, and three cleaning steps. The agent accurately adsorbs and reduces the cassiterite content in the cassiterite ore, achieves efficient recovery of fine and micro-grained cassiterite, improves the effective recovery of cassiterite, and significantly improves the tin grade and recovery rate in the tin concentrate.

The invention relates to a fast-curing bi-component condensation dealcoholization type silicone adhesive and a preparation method thereof. The fast-curing bi-component condensation dealcoholization type silicone adhesive is prepared from a component A and a component B, wherein the component A comprises hydroxyl silicone oil or alkoxy silicone oil, filler A, a cross-linking agent, a coupling agent and a catalyst; the component B is prepared from inert silicone oil, a Burge reagent (N-(triethyl ammonium sulfonyl) methyl carbamate) and a filler B. In the curing process of the adhesive, the organic silicon condensation dealcoholization vulcanization reaction and the Burge reagent are used as dehydrating agents for alcohol dehydration alkene reaction to achieve a synergistic catalysis effect, room-temperature rapid deep curing of the dealcoholization type organic silicon adhesive is finally achieved, and the curing depth of an adhesive layer within 4 hours can be larger than or equal to 20 mm; the adhesive is suitable for application scenes requiring room-temperature rapid curing or deep encapsulation and the like, and the production efficiency can be remarkably improved.

The present invention relates to methyl {4,6-diamino-2-[5-fluoro-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridin-3-yl]pyrimidin-5-yl}carbamate in the form of a novel active compound product having improved properties, for example in respect of the isolability of the active compound product, the dischargeability of the active compound product after isolation and drying and also conveyability, sieveability and micronizability of the active compound product, and to processes for the production and formulation thereof.

The invention discloses a synthesis method of 5-amino-8-formic acid-3, 4-dihydroisoquinoline-2, 8 (1H)-carboxylic acid tert-butyl ester, and relates to the technical field of organic synthesis. The synthetic method provided by the invention comprises the following steps: (1) carrying out carbonylation reaction on 5-amino-8-bromo-2-tert-butyloxycarbonyl-1, 2, 3, 4-tetrahydroisoquinoline, [1, 1 '-bis (diphenylphosphino) ferrocene] palladium dichloride and carbon monoxide to obtain 5-amino-8-methyl formate-3, 4-dihydroisoquinoline-2, 8 (1H)-carboxylic acid tert-butyl ester; and (2) carrying out saponification reaction on the 5-amino-8-formic acid-3, 4-dihydroisoquinoline-2, 8 (1H)-carboxylic acid tert-butyl ester and sodium hydroxide to obtain the 5-amino-8-formic acid-3, 4-dihydroisoquinoline-2, 8 (1H)-carboxylic acid tert-butyl ester. According to the invention, 5-amino-8-bromo-2-tert-butyloxycarboryl-1, 2, 3, 4-tetrahydroisoquinoline, sodium hydroxide and the like are taken as raw materials, the 5-amino-8-formic acid-3, 4-dihydroisoquinoline-2, 8 (1H)-carboxylic acid tert-butyl ester is synthesized through a two-step reaction, the synthesis path is short, the synthesis method is simple, and the product yield is high.

This invention relates to the field of exhaust gas treatment technology, specifically disclosing an exhaust gas treatment device for methyl carbamate containing phosgene, including an alkaline scrubbing tower, an inlet pipe, and an outlet pipe. The alkaline scrubbing tower is equipped with multiple alkaline solution feed pipes. The bottom of the alkaline scrubbing tower is connected to a collection tank, which is connected to a treatment tank. A pusher head assembly is installed in the collection tank, and the pusher head assembly is connected to a pusher power assembly, which drives the pusher head assembly to move. After the pusher power assembly moves a certain distance, it pushes the discharge baffle to rotate upwards. At this time, wastewater accumulates near the discharge baffle under the pusher head assembly's influence. The wastewater then flows out from the gap between the discharge baffle and the inner wall of the collection tank. During this process, the gap must always be smaller than the wastewater level. Finally, the bottom plate of the pusher head assembly presses against the discharge baffle, sealing the drain outlet again. The exhaust gas inside the alkaline scrubbing tower can only be discharged from the drain outlet after mixing with the alkaline solution.

The utility model mainly relates to the technical field of tail gas treatment, and provides a methyl carbamate ammonia-containing tail gas treatment device which structurally comprises an operation support, a Roots blower is fixedly arranged at the bottom of the operation support, material grooves are fixedly formed in the front side and the rear side of the right end of the operation support respectively, and transition pipes are fixedly arranged at the bottoms of the material grooves. The bottom of the transition pipe is fixedly connected with a feeding port in the right end of the auger conveyor, methyl carbamate powder in the trough and the transition pipe is conveyed into the collecting barrel through the auger conveyor, the powder is raised and scattered in the collecting barrel, and the powder is conveyed through the auger conveyor and scattered in the collecting barrel. At the moment, the Roots blower is matched with the exhaust pipe, air exhaust treatment is carried out in the collecting barrel through the filter cartridge and the dust filtering cloth bag, and air in the collecting barrel is pumped into the dilute acid spraying kettle to be treated.

This invention discloses a method for preparing albendazole, belonging to the field of pharmaceutical preparation technology. The method includes: (1) cyclization reaction: using methyl cyanocarbamate and 4-(propylthio)phenyl-1,2-diamine or their hydrochloride as raw materials, reacting in water, methanol, ethanol or a mixed solvent in the presence of an acidic catalyst or an alkaline buffer; (2) crystallization and separation of crude product: adjusting the pH of the reaction solution to 3-5, and separating the solid and liquid to obtain the crude product; (3) washing and purification: the crude product is washed successively with toluene, methanol and water, and dried to obtain the purified product; (4) refining and post-treatment: dissolving, decolorizing and recrystallizing with a formic acid-water mixed solvent, drying, pulverizing and sieving, and packaging to obtain the finished product. This invention uses a green and environmentally friendly solvent system, suppresses side reactions through precise pH control, optimizes the three-stage washing and recrystallization process, achieves a molar yield of over 88%, a purity of 99.85%, meets pharmaceutical standards, and is suitable for large-scale production.

Fungicidal compositions comprising strobilurins The present invention relates to fungicidal compositions comprising at least one compound selected from the group consisting of (I-1) methyl N-[[5-[1-(2,6-difluoro-4-isopropyl- phenyl)pyrazol-3-yl]-2-methyl-phenyl]methyl]carbamate, (I-2) methyl N-[[5-[1-(4-cyclopropyl-2,6- difluoro-phenyl)pyrazol-3-yl]-2-methyl-phenyl]methyl]carbamate, (I-3) methyl N-[[5-[1-(4-chloro- 2,6-difluoro-phenyl)pyrazol-3-yl]-2-methyl-phenyl]methyl]carbamate, (I-4) methyl N-[[5-[1-[2,6- difluoro-4-(trifluoromethyl)phenyl]pyrazol-3-yl]-2-methyl-phenyl]methyl]carbamate, and as active component 2) at least one compound selected from the group consisting of (II-1) metarylpicoxamid, (II-2) fluoxytioconazole, (II-3) bifemetstrobin, (II-4) cyclobutrifluram or an N- oxide, or an agriculturally useful salt thereof, wherein the weight ratio of compound I to compound II is from 10:1 to 1:10. The invention also relates to an agrochemical composition comprising the composition and a solvent of solid carrier. Further, the invention relates to a non- therapeutic use of the inventive compositions controlling phytopathogenic harmful fungi.

The manufacturing method of the light-transmitting waterproof glue of the present invention includes: providing raw materials: acrylate, methyl carbamate, crosslinking agent, ultraviolet absorber, antioxidant and plasticizer; mixing the above raw materials evenly in proportion to form a viscous solution; and stirring, adjusting, extruding and roll-pressing the viscous solution to form the light-transmitting waterproof glue. This method is simple and low-cost, and the prepared glue has improved high light transmittance, excellent waterproof performance and strong adhesive force.

The invention discloses methyl cyanamide synthesis technique, belongs to the field of pharmaceutical synthesis technology, synthesis technique, comprises the following steps:By grafted carrier, toluene, methacryloylpropyl dimethyl benzyl ammonium chloride and azobisisobutyronitrile mixing, under nitrogen protection condition, 80 DEG C of stirring reactions 7 8h, after reaction terminates, through filtration, vacuum drying, obtain supported catalyst;Cyanamide is diluted with water, methyl chloroformate is subsequently added, and it is regulated that reaction system pH value is 9 11, adds supported phase-transfer catalyst, and setting temperature is 45 50 DEG C, stirring reaction, obtains methyl cyanamide.The process flow of the present invention is simple, by the control of reaction conditions and the operation such as adding supported phase-transfer catalyst in technique, improve reaction efficiency, reduce the generation of by-products, improve product purity.

This invention relates to a method for the efficient preparation of methyl cyanurate, belonging to the technical field of pharmaceutical intermediate synthesis. The method includes the following steps: mixing 1-hydroxyethyl-3-methylimidazolium acetate with a 28-32% potassium phosphate aqueous solution at a mass ratio of (2.8-3.2):1, followed by allowing the mixture to stand and separate into upper and lower phases; adding a cyanamide aqueous solution to the lower phase; and continuously adding methyl cyanurate to the upper phase; stirring the reaction at 40-50°C for 1.5-2.5 hours; allowing the mixture to stand and separate into upper organic and lower brine phases; diluting the upper organic phase with 1.8-2.2 times its volume of deionized water, precipitating a solid, followed by filtration; collecting the filter cake and filtrate; washing and drying the filter cake to obtain methyl cyanurate. This invention achieves directional distribution of reactants, precise suppression of side reactions, and efficient separation of products by constructing a two-phase aqueous system.

The invention discloses a preparation method of ensafenetine, and belongs to the field of medicine synthesis. The preparation method comprises the following steps: by taking 9, 10-dimethoxy-2-(2, 4, 6-trimethyl phenyl imino)-3, 4, 6, 7-tetrahydro-2H-pyrimido [6, 1-a] isoquinoline-4-ketone (SM) as a raw material, reacting with chloroethylamine hydrochloride under an alkaline condition to prepare an intermediate 1; the intermediate 1 reacts with methyl carbamate to prepare Ensifentraine drug molecules, the two-step yield is 65% or above, and the purity is 99% or above. The method is simple in operation process, the product is easy to purify, the yield is high, the product purity is high, and a new method is provided for preparation of an ensefentin raw material medicine.

The invention belongs to the technical field of medicines, and particularly relates to a group of butyrylcholine esterase (BChE) inhibitors with high selectivity and a screening method thereof, in particular to two BChE specific inhibitors, namely methyl 4-hydroxybenzyl carbamate and moringa seed extract, which are screened from a moringa seed extract. The invention also relates to application of the BChE specific inhibitor in preparation of drugs for preventing or treating Alzheimer's disease. The invention provides a brand new strategy for efficiently screening the anti-Alzheimer disease medicine.

The invention discloses a post-treatment method for synthesis of methyl carbamate, which belongs to the technical field of synthesis of methyl carbamate, and mainly comprises the following steps: heating reaction production residues obtained in synthesis of methyl carbamate by a urea alcoholysis method to react, converting urea into biuret, and further reacting under the action of a zinc ion loaded molecular sieve to obtain the methyl carbamate. According to the method, biuret and zinc ions are subjected to a coordination reaction, a formed coordination compound is stable in structure, high in selectivity and high in reaction activity, the low-content biuret in a system can be removed as much as possible, the biuret is gradually adsorbed on the molecular sieve and then removed through filtration, and finally, residual liquid is recrystallized, so that the biuret is obtained. The residual methyl carbamate product in the reaction production residues is obtained, so that the reaction production residues are recycled. Through the post-treatment step, the recovery rate of methyl carbamate can be increased, residual compounds in the residues can be converted and removed, and then compounds such as biuret in the residues are prevented from polluting the environment.

The invention belongs to the technical field of organic synthesis, and discloses an application of Bacillus megaterium in the synthesis of 5-aminobenzimidazole-2-methyl carbamate. The present invention adopts Bacillus megaterium JOM-01 to reduce 5-nitrobenzimidazole-2-methyl carbamate to 5-aminobenzimidazole-2-methyl carbamate, and provides a nitro reduction green biosynthetic pathway. The synthesis method has the advantages of less three wastes, low production cost, mild production conditions, strong selectivity, easy operation, relatively high yield, and conducive to promotion and application. The present invention is applicable to the preparation field of albendazole and its intermediates.

This invention relates to a method for preparing compound (I) or a pharmaceutically acceptable salt or solvate thereof. In particular, such a method comprises the dehydration cyclization of a 1,2-diacylhydrazine intermediate to form the corresponding 1,3,4-oxadiazole, wherein the dehydration cyclizing agent may be N,N-dimethylaminosulfonyl chloride, N-(triethylammonium sulfonyl)carbamate, phosphorus trichloride, or phosphorus pentachloride, resulting in increased product yield and purity compared to known methods. Compound (I) and pharmaceutical compositions thereof can be used as respiratory syncytial virus (RSV) inhibitors.