6 results about "Methyl carbamate" patented technology

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.

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.

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.

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.

The application discloses a zinc-aluminum composite oxide catalyst and a preparation method and application thereof, and belongs to the technical field of catalytic materials and non-phosgene isocyanate preparation. The application solves the problems of high reaction temperature, low raw material concentration, many side reactions and insufficient catalyst stability in the process of preparing isocyanate by pyrolysis of carbamic acid ester. The zinc-aluminum composite oxide catalyst comprises a composite oxide of zinc and aluminum, and has a dual-phase heterogeneous structure of ZnO and ZnAl2O4 spinel. When the catalyst is applied to the preparation of 4-(4'-phenylaminomethylcarbamate) diphenyl methane isocyanate (MMI) and diphenyl methane diisocyanate (MDI) by vacuum thermal decomposition of diphenyl methane diamino methylcarbamate (MDC), the self-polymerization and condensation side reactions in the reaction process can be effectively inhibited by the synergistic effect of the ZnO phase and the spinel phase, the selectivity and yield of the target product are improved, and the catalyst has good mechanical stability and is easy to recycle and cyclically used.