52 results about "Diisobutylaluminum hydride" patented technology

The invention relates to a sulfoacid rare earth catalyst for polymerizing high-cis-isoprene rubber and a preparation method thereof. The catalyst comprises benzenesulfonic acid neodymium rare earth complex and alkyl aluminum; the molar ratio of the alkyl aluminum to the rare earth neodymium in the benzenesulfonic acid neodymium rare earth complex is 15 to 40:1, wherein the benzenesulfonic acid neodymium rare earth complex comprises benzenesulfonic acid neodymium alcohol complex, benzenesulfonic acid neodymium sulphoxide complex, benzenesulfonic acid neodymium furan complex, benzenesulfonic acid neodymium amine complex, benzenesulfonic acid neodymium ether complex and benzenesulfonic acid neodymium ester complex; ligand comprises: alcohol compound, sulfoxide compound, furan compound, amine compound, ether compound and ester compound; and the alkyl aluminum comprises: 3-isobutyl aluminum, triethyl aluminum, diisobutyl aluminum hydride, or diethyl aluminum hydride. The sulfoacid rare earth complex catalyst is used for polymerizing isoprene, and can obtain the high-cis rare earth polyisoprene rubber with the cis 1,4 structure content more than 96.0 percent and the weight-average molecular weight more than 2.2 million.

A composition comprising at least 93% (w/w) neopentasilane; and a method of preparing neopentasilane, the method comprising treating a tetrakis-(trihalosilyl)silane with diisobutylaluminum hydride.

The invention discloses a method for preparing alpha-AlH3 under the control of a diisobutylaluminum hydride crystal transformation assistant. The method comprises the following steps: 1, dissolving AlH3 etherate and diisobutylaluminum hydride in anhydrous toluene or benzene, stirring at 92-94DEG C for 2-3h until a reaction ends, and standing until room temperature; and 2, filtering to obtain a white reaction product, washing by using ether 2-4 times, washing by using dilute hydrochloric acid 1-2 times, washing by using deionized water 2-3 times, and carrying out vacuum drying at 40-90DEG C for 5-8h under a degree of vacuum of 5-20Pa to obtain a white powder product. The method allows the above raw material to react under the action of the diisobutylaluminum hydride crystal transformation assistant in order to generate high yield alpha-AlH3, and realizes no side reactions.

The invention belongs to the technical field of chemical synthesis of essences and flavors and particularly relates to a (4S, 7RS)-galaxolide synthesis method. The method includes: subjecting bromo-pentamethyl indane and metallic magnesium to reaction to generate a Grignard reagent, and then subjecting to reaction with tetramethoxyl silane to obtain pentamethyl indane silane; subjecting the pentamethyl indane silane to asymmetric Hiyama cross coupling reaction with racemic 2-bromopropionate under catalysis of (1S, 2S)-N,N-dimethyl-1,2-diphenyl diaminoethane and nickel chloride to synthesize (S)-hexamethyl indane acid ester; reducing the (S)-hexamethyl indane acid ester by diisobutyl aluminum hydride (DIBAL-H) to obtain (S)-hexamethyl indanol, and finally subjecting to reaction with paraformaldehyde to obtain (4S, 7RS)-galaxolide. The (4S, 7RS)-galaxolide synthesis method is simple in synthetic route and mild in reaction condition, the overall yield reaches 40%, and product optical purity is 91%.

The invention discloses a preparation method of Mirabegron and relates to the technical field of medicine preparation. The preparation method includes the steps of subjecting R-mandelic acid and 4-nitrophenylethylamine to amide condensation reaction to obtain an intermediate (R)-N-(4-nitrophenethyl)-2-hydroxy-2-phenylacetamide, reducing amide carbonyl through diisobutyl aluminium hydride to obtainan intermediate (alphaR)-alpha-[[[2-(4-Nitrophenyl)ethyl]amino]methyl]benzenemethanol hydrochloride, reducing nitryl through a ammonium formate-Pd/C reduction system to obtain an intermediate 2-[2-(4-amino-phenyl)-ethylamino]-1-phenyl-ethanol, and finally subjecting the intermediate and (2-aminothiazole-4-yl)acetic acid to condensation reaction to obtain Mirabegron. The Mirabegron prepared by themethod has high purity and high yield; the preparation method needs fewer steps of synthesis route and mild and controllable reaction conditions, is easy and convenient in operation, low in cost andadaptable to industrial production, and has broad prospect and high industrial application value.

This invention provides a method for generating secondary phosphines from secondary phosphine oxides in the presence of a reducing agent, such as diisobutylaluminum hydride (DIBAL-H), triisobutyldialuminoxane, triisobutylaluminum, tetraisobutyldialuminoxane, or another reducing agent comprising: (i) an R₁R₂AlH moiety, wherein R₁ and R₂ are each an alkyl species or oxygen, and wherein at least one of R₁ or R₂ comprises at least 2 carbon atoms, or (ii) an R₁R₂R₃Al moiety, wherein R₁, R₂, and R₃ are not hydrogen, and wherein at least one of R₁, R₂, and R₃ is an alkyl species comprising a β-hydrogen, not including triethylaluminum. Preferred reducing agents for the present invention include: diisobutylaluminum hydride, triisobutyldialiuminoxane, triisobutylaluminum, tetraisobutyldialuminoxane, and combinations thereof.

The invention discloses an environmentally-friendly multi-effect antirust oil. The environmentally-friendly multi-effect antirust oil comprises, by weight, 61-70 parts of 75SN base oil, 10-18 parts of 150SN base oil, 5-7 parts of sodium petroleum sulfonate, 1-2 parts of sorbitan monostearate, 5-7 parts of calcium petroleum sulfonate, 0.1-0.2 parts of diisobutyl aluminum hydride, 1-2 parts of sodium hypophosphate, 2-3 parts of zinc dialkyl dithiophosphate, 0.5-1 part of tris(2,4-di-tert-butylpheny)phosphite, 2-3 parts of oleic acid and 10-14 parts of a film forming assistant. The antirust oil can be used for the rust prevention of various metal components, can meet antirust requirements of many metal materials comprising castings, steel, copper, aluminum and the like, is compatible with automobile oil, has no influences on the lubrication performance of lubrication oil, and has the advantages of thin oil film, easy cleaning, reasonable compounding of raw materials, safety and environmental protection.

The invention discloses a natural product (+)-Strictifolione synthetic method. The method comprises the steps that 3-benzenepropanal and an Evans chiral auxiliary reagent are subjected to an aldol reaction for diisobutyl aluminum hydride reduction and then subjected to an addition reaction with metal indium activated 3-propylene bromine to obtain a compound shown in the formula 5; silyl enol ether reacts with acrolein under the action of titanium tetraisopropoxide and (R)-1,1-binaphthol, then carbonyl is reduced through sodium borohydride, p-toluenesulfonic acidpyridinium salt is used for cyclization, and acidification treatment is carried out after a methylsulfonyl group becomes a leaving group to obtain a compound shown in the formula 11; a Grubbs second-generation catalyst is used for carrying out a metal coupling reaction on the compounds shown in the formulas 5 and 11 to obtain (+)-Strictifolione. According to the bisection synthetic method, the design is simple and reasonable, operation is easy and convenient, the reaction condition is moderate, linear steps are simple, the product yield is high, and the production cost is greatly reduced.

The invention discloses a catalyst charging method in neodymium polybutadiene rubber polymerization processes. The catalyst charging method comprises following steps: (1) ethylaluminum sesquichloride, diisobutylaluminum hydride, and neodymium neodecanoate are mixed according to a certain ratio so as to obtain a mixed catalyst, the mixed catalyst is delivered into a static mixer for ternary aging, wherein aging time ranges from 25 to 35min, and aging temperature ranges from 25 to 35 DEG C; (2) the mixed catalyst obtained via aging is delivered into a premixing kettle with a mixture of butadiene and a solvent oil for buffer treatment, and then an obtained mixed material is delivered into a polymerization kettle for polymerization, wherein pressure of the polymerization kettle ranges from 0.35 to 0.45 MPa, a first polymerization kettle temperature ranges from 60 to 75 DEG C; and (3) a part of diisobutylaluminum hydride is directly added through the middle-lower part of the premixing kettle into the polymerization kettle without aging, and is reacted with the mixed material obtained via step (2) for polymerization so as to prepare polybutadiene rubber. Beneficial effects of the catalyst charging method are that: reaction is stable; activity is stable; temperature is stable; the catalyst charging method is beneficial for Mooney viscosity control; and polybutadiene rubber product quality is stable.

The invention relates to a synthetic method of beraprost. The synthetic method comprises the following steps: with an intermediate I as an initial raw material, carrying out selective primary alcoholoxidation and a Witting reaction to obtain an intermediate V; carrying out reduction and column chromatography purification on the intermediate V to obtain an intermediate IV; and hydrolyzing the intermediate IV to obtain beraprost. According to the synthetic method disclosed by the invention, two hydroxyl groups of the intermediate I are selectively oxidized, so a hydroxyl protection reagent is prevented from being used; in the oxidation step, ultralow-temperature (-60 to -80 DEG C) reactions and use of a reagent DCC with relatively high toxicity are avoided; in the reduction step, diisobutylaluminum hydride is prevented from being used; process operation units are greatly reduced, reaction steps are shortened, emission of three wastes is reduced, and the reactions are more efficient andenvironment-friendlier; and the main peak content of the prepared beraprost reaches 99.0% or above, and total process yield reaches 26% or above. The invention provides the synthetic method which ismore beneficial for industrial production.

The invention discloses a method for synthesizing di-tert-butylphenylphosphonium tetrafluoroborate, and belongs to the field of organic synthesis. The method comprises the following steps: in the anhydrous and anaerobic atmospheres, taking dichlorophenylphosphine as a raw material, after the reduction of diisobutyl aluminium hydride, reacting with tertiary butanol under the catalytic action of boron trifluoride, and then carrying out hydrolysis to generate the di-tert-butylphenylphosphonium tetrafluoroborate. Compared with the prior art, the method is high in yield and simple in aftertreatment, and is more applicable for industrial production.

The invention discloses a method for synthesizing N-Boc-3-pyrrolidine formaldehyde, which comprises the following steps of: (1) adding 1mol of glycine and 0.5 to 1.5mol of acrylonitrile into a methylbenzene solvent, refluxing the solution under the action of 1.5 to 2.5mol of paraformaldehyde, cooling and then performing suction filtering on the solution, concentrating the mother solution, distilling the mother solution under reduced pressure, and collecting the fraction of 102 to 105 degrees to obtain 3-cyanopyrrolidine; (2) adding 0.5mol of 3-cyanopyrrolidine obtained in the step (1) into dichloromethane, dripping 0.4 to 0.6mol of Boc acid anhydride into the solution at room temperature under the action of 0.5 to 0.75mol of triethylamine, performing room temperature reaction, washing the reaction solution by using hydrochloric acid solution, and separating, drying and concentrating the solution to obtain N-Boc-3-cyanopyrrolidine; and (3) dissolving 0.4mol of N-Boc-3-cyanopyrrolidine obtained in the step (2) into dichloromethane, cooling the solution, dripping 0.4 to 0.6mol of di-isobutyl aluminum hydride into the solution, dripping hydrochloric acid solution into the reaction solution after reaction to quench the reaction, separating the solution, concentrating the organic phase, distilling the concentrate under reduced pressure, and collecting the fraction of 110 to 114 degrees to obtain the N-Boc-3-pyrrolidine formaldehyde. The synthesizing method has a few steps, high yield and low cost, and is suitable for industrial large-scale production.

The invention relates to a method for preparing alpha-AlH3 by use of diisobutylaluminum hydride and LiBH4 as the catalyst, relates to a preparation method for alpha-AlH3, and aims to solve the problem that conditions required by direct synthesis of alpha-AlH3 through aluminum and hydrogen are strict. The method comprises the following steps: adding aluminum powder, diisobutylaluminum hydride and LiBH4 in an autoclave; introducing hydrogen, reacting at the condition with the temperature of 100-150 DEG C, and drying to obtain the product. In the method, the reaction pressure is 10-15 MPa which is much lower than 10 GPa, the reaction temperature is 100-150 DEG C which is much lower than 650 DEG C, through XRD tests, the synthesized product contains alpha-AlH3, and the method is applied to preparation of alpha-AlH3.

The invention discloses a novel synthesis method for a key intermediate of the anti-hepatitis B drug Entecavir. The method is characterized in that a known compound as shown by Formula 1 is adopted asa starting material, and synthesis of target molecules is achieved through a series of reaction steps such as Evans aldol reaction, hydroxyl protection through tert-butyldimethylsilyl chloride, reductive removal of a chiral auxiliary group through diisobutyl aluminum hydride (DIBAL-H) to obtain an aldehyde, addition of a Grignard reagent into the aldehyde, protection of a newly generated hydroxylthrough tert-butyldimethylsilyl, double-bond epoxidation reaction, free-radical ring closing reaction, hydroxyl protection through p-methoxybenzyl, etc. The method disclosed by the invention has theadvantages of unique and novel designing of the whole route, mild reaction conditions for the reaction steps, high rate, relatively fewer side effects, and high simplicity and convenience in operation; and common chemical reagents are adopted in the route, and raw materials are cheap and can be easily obtained, so that the synthesis cost can be greatly reduced.

The invention discloses a preparation method of pramipexole hydrochloride. The method comprises the following steps: protecting an amino group of aminocyclohexanol by means of condensation of propionyl chloride to obtain p-propionyl cyclohexanol; then, carrying out catalytic oxidation to obtain p-propionyl cyclohexanone; carrying out oxidative bromination and Hantzsch condensation to obtain 2-amino-6-propionylamino-4, 5, 6, 7-tetrahydrobenzothiazole; then, reducing by using diisobutylaluminum hydride to obtain 2-amino-6-propylamino-4, 5, 6, 7-tetrahydrobenzothiazole; finally, carrying out L-(+)-tartaric acid separation and salification to obtain the pramipexole hydrochloride. The preparation method, provided by the invention, of pramipexole hydrochloride is low in price of raw materials, easy in obtaining of the raw materials, convenient and simple to operate, novel in route, environmentally-friendly and high in yield; the prepared pramipexole hydrochloride is good in purity.