118 results about "Elimination reaction" patented technology

The invention relates to the technical field of organic chemical synthesis, and particularly discloses a method for producing hexafluorobutadiene, a continuous production system and application thereof. The method for producing hexafluorobutadiene comprises the following steps: (1) bromination reaction: reacting tetrafluoroethylene with liquid bromine to generate dibromotetrafluoroethane; (2) telomerization reaction: reacting the dibromo tetrafluoroethane with tetrafluoroethylene under the action of a catalyst to generate dibromo octafluorobutane; the catalyst is cuprous bromide; and (3) elimination reaction: reacting the dibromo octafluorobutane under the action of a Grignard reagent to generate hexafluorobutadiene. The method provided by the invention has the advantages of simple process, easily available raw materials, high production efficiency, continuous production, low production cost and industrial mass production value.

The invention provides an ultrasonic activated azido precursor, a prodrug and application. The precursor and an active drug react and are bonded to obtain the azido prodrug; the bonding group of the active medicine is amino, hydroxyl or sulfydryl; a bonding group of the ultrasonic activated azido precursor is an ester group. Novel ultrasonic activatable groups, namely p-azidobenzyloxycarbonyl and derivatives thereof, are adopted, hydrogen atoms on a benzene ring are substituted to different degrees, the reducing capacity of a precursor can be remarkably improved, azide is effectively reduced into amino through ultrasonic stimulation under the action of TBR and NADH, and then a self-elimination reaction is induced to release active drugs. The structure has the advantages that different types of active drugs (active pharmacodynamic groups can be amino, hydroxyl and sulfydryl) can be bonded through 4-nitrophenyl carbonate, high-selectivity reduction is performed under the triple action of ultrasound, TBR and NADH, active raw drugs are released according to needs, and toxicity reduction and synergism are achieved.

Hydrogels that degrade under appropriate conditions of pH and temperature by virtue of crosslinking compounds that cleave through an elimination reaction are described. The hydrogels may be used for delivery of various agents, such as pharmaceuticals.

The invention discloses a synthesis method of an indaziflam intermediate 2, 6-dimethyl-indene amine. In the invention, indanone is reduced by using a cheap reducing reagent to prepare indanol, the indanol and sulfonyl chloride are subjected to an elimination reaction to prepare indene, and finally, the indene and an amination reagent are subjected to addition to prepare the 2, 6-dimethyl-indene amine. The route is good in reaction selectivity and few in side reaction, and the total yield of the 2, 6-dimethyl-indene amine can reach 70% or above. The method is mild in reaction condition, easy to control, less in three wastes, simple in whole process operation and easy to industrialize.

The invention provides a method for preparing p-chloromethyl styrene, which comprises the following steps: (1) in the presence of a catalyst and an assistant, carrying out reaction on paraformaldehyde and hydrogen chloride to obtain a chloromethylation reagent; (2) reacting beta-halogenated ethyl benzene with the chloromethylation reagent obtained in the step (1) to obtain chloromethyl halogenated ethyl benzene; (3) adding an extracting agent into the chloromethyl halogenated ethylbenzene reaction liquid obtained in the step (2) for extraction to obtain an oil layer containing chloromethyl halogenated ethylbenzene and a water-containing acid layer, and crystallizing the oil layer to obtain purified p-chloromethyl halogenated ethylbenzene; and (4) in the presence of a solvent, carrying out elimination reaction on the purified p-chloromethyl halogenated ethyl benzene and alkali to obtain p-chloromethyl styrene.

The invention relates to the technical field of pharmaceutical chemicals, in particular to a preparation method of 11beta, 17alpha-dyhydroxyl-6 alpha-methylpregna-4-ene-3, 20-diketone, and discloses a preparation method of 11beta, 17alpha-dyhydroxyl-6 alpha-methylpregna-4-ene-3, 20-diketone. The method comprises the following steps: S1, adding a 11beta, 17alpha-dyhydroxyl-6 alpha-methylpregna-4-ene-3, 20-diketone crude product into a mixed solution of a solvent A and a solvent B, heating to 25-35 DEG C, and stirring for dissolving until the solution is clear, so as to obtain a 11beta, 17alpha-dyhydroxyl-6 alpha-methylpregna-4-ene-3, 20-diketone crude product; s2, carrying out transposition elimination reaction; s3, carrying out acidification deprotection reaction; s4, adjusting the pH value; s5, standing and layering; s6, decoloring; s7, performing concentration; s8, cooling and crystallizing; s9, carrying out solid-liquid separation; and S10, carrying out vacuum drying, so as to obtain a finished product of the 11beta, 17alpha-dyhydroxyl-6 alpha-methyl pregna-4-ene-3, 20-diketone. The method has the characteristics of high yield and good product quality, is stable and is easy to realize industrial production.

The invention relates to the technical field of catalytic synthesis, in particular to a chloromethylation catalyst, a preparation method of the chloromethylation catalyst and a method for preparing high-purity ortho-position, meta-position and para-position chloromethyl styrene through the chloromethylation catalyst, and the chloromethylation catalyst is prepared by loading sulfonic acid compounds and (or) pyridine compounds and (or) copper salt on a molecular sieve. The method can improve the localization selectivity of chloromethylation. The method for preparing high-purity ortho-position, meta-position and para-position chloromethyl styrene comprises the following steps of: reacting beta-bromophenylethane, paraformaldehyde and lewis acid in the presence of the chloromethylation catalyst to generate chloromethyl beta-bromophenylethane, and then performing elimination reaction under an alkaline condition to generate a chloromethyl styrene crude product; the high-purity ortho-position, meta-position and para-position chloromethyl styrene is obtained after the crude product is rectified, the brand-new catalyst is adopted in the method, the reaction selectivity is enhanced, the process is simple, and industrial production is facilitated.

The invention discloses a synthesis method of piperonone, and relates to the technical field of flavors, fragrances and chemical engineering, and the synthesis method comprises the following steps: taking acrylate as a raw material, and carrying out Michael addition reaction with isobutene under the action of Lewis acid to obtain 5-methyl-5-hexenoic acid ethyl ester; the preparation method comprises the following steps: carrying out nucleophilic substitution reaction on ethyl 5-methyl-5-hexenoate and bromoisopropane under the action of a basic catalyst to obtain ethyl 5-methyl-2-isopropyl-5-hexenoate; carrying out self Friedel-Crafts acylation reaction on the 5-methyl-2-isopropyl-5-hexenoic acid ethyl ester under the action of Lewis acid, so as to obtain 5-methyl-2-isopropyl-5-chloro cyclohexanone; and carrying out elimination reaction on the 5-methyl-2-isopropyl-5-chlorocyclohexanone under the action of alkali to obtain the product piperonone. According to the synthetic route, conventional chemical reagents are used as raw materials, reaction conditions are mild, emission of three wastes is reduced to a great extent, and the synthetic route is more environmentally friendly and suitable for continuous industrial production.

The application provides a preparation method of high-purity pyromellitic dianhydride, which is prepared from 2,3-dichloromaleic anhydride as raw material, and sequentially subjected to Diels-Alder cycloaddition reaction, elimination reaction and oxidation reaction to obtain high-purity pyromellitic acid, and then subjected to dehydration treatment to obtain high-purity pyromellitic dianhydride. In the preparation method, pyromellitic acid is used as a dehydration raw material to prepare anhydride, so that intermediate acid by-products are not easy to be generated, and the product purity is improved; the dehydration reaction is promoted by adopting azeotropic distillation and separation coupling, so that the reaction yield is improved; the preparation steps are few, the reaction process is simple, the reaction condition is mild, the raw materials are economically inexpensive and easy to obtain; the catalyst or the aid used in each step does not generate harmful substances, and is green and environment-friendly.

The invention relates to an industrial preparation method of an intermediate 5alpha-androstane-2-ene-17 ketone, the intermediate is a rocuronium bromide intermediate, and the method comprises the following steps: taking epiandrosterone as a starting material, and reacting with paratoluensulfonyl chloride to obtain a compound I; and carrying out elimination reaction on the compound I in organic alkali or a DBU catalyst to obtain the compound 5 alpha-androstane-2-ene-17 ketone. The method is good in elimination reaction selectivity, high in yield, good in quality, low in cost, mild in reaction condition, short in production period, recyclable in reaction solvent and green and environment-friendly in production process, and a single impurity of the product is less than 0.3%.

A full continuous-flow preparation method of (+)-biotin, including: subjecting a cyclic anhydride and a chiral biphenyl propylene glycol to asymmetric ring-opening reaction to produce a first intermediate, which undergoes selective reduction with a borohydride and cyclization with an inorganic mineral acid to produce (3aS, 6aR)-lactone; subjecting the (3aS, 6aR)-lactone and a sulfenylating reagent to sulfenylation to produce (3aS, 6aR)-thiolactone, which undergoes Fukuyama coupling with a zinc reagent in the presence of a palladium catalyst and elimination reaction in the presence of an inorganic mineral acid to produce an alkenyl valerate compound; subjecting the alkenyl valerate compound to reduction in the presence of a Pd / C catalyst to produce a valerate ester, which undergoes hydrolysis to produce a valeric acid salt; and subjecting the valeric acid salt to debenzylation in the presence of an inorganic mineral acid to produce the target product (+)-biotin.

The invention discloses a preparation method of a dual-response fluorescent probe based on an isatin hydrazone-pyrazole Schiff base structure, the dual-response fluorescent probe is synthesized by carrying out nucleophilic addition-elimination reaction on amino-functionalized isatin hydrazone and aldehyde group modified pyrazole, and the chemical structural formula of the dual-response fluorescent probe is as follows: # imgabs0 #. The probe disclosed by the invention has high specific recognition capability on Cu < 2 + > and CN <->. The probe shows fluorescence quenching response to Cu < 2 + >, the response time is short, and the anti-interference capability is strong. The probe realizes selective recognition of CN <-> in a fluorescence'opening 'mode, and shows a dual recognition signal of CN <-> along with obvious solution color change.

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 application discloses a new method for synthesizing dihydrogibberellin without protecting carboxyl. The application provides a new method for synthesizing dihydrogibberellin without protecting carboxyl, which comprises the following steps: 1) mixing a compound shown in formula II with a catalyst A in an organic solvent B, and carrying out a hydrogen reduction reaction under a hydrogen atmosphere to obtain a compound shown in formula III; 2) mixing the compound shown in formula III with a saturated aqueous solution of a base in an organic solvent C, and carrying out a selective deacetylation reaction to obtain a compound shown in formula IV; and 3) mixing the compound shown in formula IV with triphenyl phosphine and an elimination reagent in an organic solvent D, and carrying out a dehydration elimination reaction to obtain dihydrogibberellin shown in formula V. The application can simplify the synthesis method of dihydrogibberellin and is more beneficial to large-scale production and synthesis.

The present invention relates to a compound of formula (I), a pharmaceutically or cosmetically acceptable salt thereof, or any stereoisomer thereof, wherein R’ is selected from the group consisting of H, (C1-C6)-alkyl, and (C3-C6)-cycloalkyl; R1, R2, R4, R5, R6, R7, R9, and R 10 are independently radicals selected from the group consisting of H, hydroxy, amino, (C1-C6)-alkyl, (C1-C6)-alkoxy, (C1-C6)-alkylamino, and (C1-C6)-dialkylamino; R3 and R8 are independently selected from the group consisting of (C1-C6)-alkyl, (C1-C6)-alkoxy, hydroxy, amino, (C1-C6)-alkylamino, and (C1-C6)-dialkylamino), and relates to a process for preparing the same, which process comprises a beta-elimination reaction of the corresponding alkyl halide precursor in the presence of DBU and a suitable solvent. The present invention also relates to intermediates useful in such a preparation process. [Chemical 1] TIFF2025522152000022.tif95160

The invention discloses a preparation method of an intermediate of macloxvir. The preparation method comprises the following steps: step 1, carrying out halogenation reaction; step 2, elimination reaction; step 3, addition reaction; step 4, ring closing reaction; the starting raw materials, the solvent and the catalyst selected in the invention are industrial-grade cheap and easily available products, have the advantage of low production raw material cost, and provide economic feasibility support for industrial large-scale production; reaction conditions of each step in the reaction process are mild, byproducts are few, the yield is high, and a target product can be prepared more efficiently; meanwhile, the synthesis route is high in atom utilization rate and excellent in atom economy, the used solvent and reagent are high in stability and easy to recycle and reuse, generation and emission of industrial three wastes are greatly reduced, the environment-friendly treatment cost is reduced, and the concept of green chemistry and sustainable development is met; the method gives consideration to economy, high efficiency and environmental friendliness, and solves the problems of low yield, violent reaction conditions and high cost of raw materials and auxiliary materials in the existing method.

The invention provides a synthesis method of atavapam, which comprises the following steps: carrying out nucleophilic addition-elimination reaction on commercially available raw materials and 4-methyl-3-trifluoromethylaniline under alkaline conditions, carrying out Suzuki coupling reaction under the action of a catalyst, carrying out pressurized hydrogenation, and carrying out chiral resolution, thereby obtaining the atavapam. And condensing with 2-fluoro-6-methyl benzoyl chloride under an alkaline condition, and further removing a Boc protecting group under an acidic condition to finish synthesis of the atavapam. According to the invention, a convergent synthesis process is adopted, tedious synthesis steps in the original process are shortened, and post-treatment is simpler and more controllable.

The application provides a preparation method of dydrogesterone, which comprises the following steps: performing a selective epoxidation reaction on a compound I in a first solution containing meta-chloroperoxybenzoic acid and hydrogen peroxide to obtain a compound II; the content of the meta-chloroperoxybenzoic acid in the first solution is more than 1 times of the amount of substance of the compound I; performing a reduction reaction on the compound II under the action of hydrogen and a catalyst to obtain a compound III; performing a hydrolysis reaction on the compound III in a dilute acid solution, and then performing a hydroxyl elimination reaction on the compound III in a second solution to obtain the dydrogesterone; the structural formulae of the compound I, the compound II, the compound III and the dydrogesterone are as follows:; and. The preparation method has less by-products and a higher reaction yield.

The present invention provides a process for preparing a 2-(3-alkenyl)-1,3-butadiene compound of the following general formula (A), wherein R1 and R2 represent, independently of each other, a hydrogen atom or a linear, branched, or cyclic hydrocarbon group having 1 to 20 carbon atoms and optionally having an unsaturated bond(s), the process comprising the step of subjecting a secondary allylsulfone compound of the following general formula (G), wherein R1 and R2 represent, independently of each other, a hydrogen atom or a linear, branched, or cyclic hydrocarbon group having 1 to 20 carbon atoms and optionally having an unsaturated bond(s), W represents an arenesulfonyl group, and Z represents a halogen atom, to a reductive removal of an arenesulfonyl group, W, at an allyl position, and then subjecting the secondary allylsulfone compound (G) to an elimination reaction of a hydrogen halide, HZ, in this order or in reverse order, to form the 2-(3-alkenyl)-1,3-butadiene compound (A).

The invention discloses a pyrazolo [5, 1-a] isoindole derivative as well as a synthesis method and application thereof, and belongs to the technical field of organic chemical synthesis. The invention solves the problems of harsh reaction conditions, limited substrate range and the like of continuous multi-step synthesis of a precursor in the existing pyrazolo [5, 1-a] isoindole compound synthesis process. According to the invention, a polarity reversal strategy is adopted, a cyano group is introduced into 1, 5-enyne to change the electronic characteristics of 1, 5-enyne, diazo, olefin and ethynyl benzene are reacted under mild conditions, two rings and three new chemical bonds are constructed through a series of intermolecular [3 + 2] cycloaddition, intramolecular cycloaddition and elimination reactions, and pyrazolo [5, 5-a]-1, 5-a-phenanthrene is efficiently synthesized. According to the present invention, the 1, 1-a] isoindole derivative has characteristics of good synthesis yield, simple operation of the synthesis method, easily available raw materials, good substrate universality and step economy, and provides the effective strategy for the drug design synthesis.

The invention discloses a preparation method of a chiral intermediate (S)-3-methyl-1-tert-butoxycarbonyl-1,4-diazepane for treating ocular hypertension, relating to the technical field of pharmaceutical chemicals. The invention comprises the following steps: using 1-benzyl-3-methylpiperidin-4-one as a starting raw material, performing chiral resolution to obtain an intermediate 1, performing an addition-elimination reaction on the intermediate 1 and hydroxylamine hydrochloride to obtain an intermediate 2, performing a Beckmann rearrangement reaction on the intermediate 2 to obtain an intermediate 3, performing an amino deprotection reaction on the intermediate 3 to obtain an intermediate 4, performing an amino protection reaction on the intermediate 4 and di-tert-butyl dicarbonate to obtain an intermediate 5, and performing a decarbonylation reaction on the intermediate 5 to obtain the (S)-3-methyl-1-tert-butoxycarbonyl-1,4-diazepane. The preparation method has the characteristics of readily available raw materials, a simple process and a high product yield, and is suitable for the industrial production of the (S)-3-methyl-1-tert-butoxycarbonyl-1,4-diazepane.

The present invention relates to the technical field of organic chemical synthesis, and particularly relates to a preparation method of α-carboline and its derivatives. Using a base as a promoter, under the condition of an organic solvent, an o-3-pyridyl-aniline compound reacts for 2-6 h under an inert gas condition at 80-110 °C; after the reaction is completed, water is added for quenching, and extraction is carried out with an organic solvent, followed by column chromatography separation (V 石油醚 : V 乙酸乙酯 = 10:1 to 1:10), to obtain an α-carboline derivative. The present invention uses a base as a promoter, and under an inert gas condition, an addition-elimination reaction occurs between an arylamine and the C2 position of a pyridine heterocycle in an organic solvent, and hydrogen is removed to obtain an α-carboline compound. This method has the following advantages: simple method, high atom economy, avoiding the use of expensive transition metals, mild reaction conditions, and producing environmentally friendly by-products.

This invention discloses a method for preparing trifluoromethyl olefins. The method comprises the following steps: (1) in a haloalkane solvent or ether solvent, a compound as shown in Formula I, CuX'2, CF3SO2Na, N(R) 2 (1) 4X undergoes the addition reaction shown below; (2) The product of the addition reaction in step (1) is reacted with a base in an organic solvent to undergo the elimination reaction shown below. The preparation method of trifluoromethyl olefins provided by the present invention has the advantages of being applicable to electron-rich styrene substrates, requiring less metal catalyst, not requiring high pressure conditions, not requiring photocatalysis, having easy-to-control reaction conditions, being relatively convenient for post-processing, and having a high yield.

The application belongs to the field of medicine synthesis, and particularly relates to a preparation method of 2,2-disubstituted-4-phenyl butyronitrile derivative, which comprises the following steps: mixing phenetole, nitrile and alkali agent in a molar ratio of 1.0:3.5-4.5:2.5-3.5 in aprotic solvent with a dielectric constant (epsilon) less than 20 at 60-100 DEG C for 12-30 hours; after the reaction is completed, the cooled reaction system is adjusted to be neutral, and the product is collected and purified. The phenetole is subjected to elimination reaction under alkaline conditions to generate a carbon-carbon double bond, and is subjected to addition reaction with the nitrile to obtain the 2,2-disubstituted-4-phenyl butyronitrile derivative. Meanwhile, the raw materials used are low in price and easy to synthesize, the cost is greatly reduced, the industrialization prospect is wider, and the operation is simple, so that the process technology has more competitive value.

The invention discloses a preparation method and application of a 2, 5-diketopiperazine derivative, and belongs to the field of biological medicine. The preparation method comprises the following steps: by taking 1, 4-diacetyl piperazine-2, 5-diketone (II) as an initial raw material, firstly, carrying out condensation reaction on the initial raw material and isobutyraldehyde to prepare a key intermediate (III); meanwhile, 4-amino-1-butanol (IV) is converted into an intermediate (VI) through acylation and oxidation two-step reaction; and finally, carrying out condensation and elimination reaction on the intermediates (III) and VI to prepare the target compound (I). The preparation method provided by the invention has the advantages of reasonable route design, mild conditions and outstanding stereoselectivity. According to the method, on the basis of easily available raw materials, a product mainly comprising a Z configuration is efficiently constructed through a modular strategy and consistent mild base catalysis conditions. Experimental data show that the compound prepared by the invention can inhibit TG accumulation in nematode bodies and reduce nematode fat accumulation, and can be developed into efficient medicines for preventing and treating obesity.

The invention is directed to self-eliminating cleavable conjugates according to general formula (I) or (II) wherein AR is capable of an elimination reaction upon cleavage of CL.

The application provides an intermediate for synthesizing chlorantraniliprole and cyantraniliprole and a preparation method of the intermediate, and the structural formula of the intermediate is 2-amino-3-methylbenzoic acid. The intermediate is obtained by a -D-A reaction, aromatization and a Hoffmann elimination reaction from a cheap bio-based platform compound 2-methylfuran as a starting material. The whole process does not need a dangerous nitration process and a hydrogenation process, the process has mild reaction conditions, good operability, less wastewater and a high yield of the obtained intermediate, and is very suitable for industrialized preparation of an intermediate required by the high-efficiency insecticides chlorantraniliprole and cyantraniliprole.

This invention discloses a method for synthesizing vinylene carbonate. The method includes: reacting chlorovinyl carbonate with triethylamine in the presence of compounds such as oxanthracene or thioxanthracene to generate a vinylene carbonate reaction solution; and then subjecting the reaction solution to vacuum filtration, distillation, and crystallization to obtain electronically pure vinylene carbonate (purity can reach 99.995% or higher). This method can effectively inhibit the polymerization of vinylene carbonate, avoid the formation of vinylene carbonate polymers, improve the yield of the elimination reaction and the overall heat transfer efficiency of the distillation process, reduce the difficulty of separation and purification, and reduce energy consumption, making it suitable for industrial production.

The invention provides a method for preparing p-isopropenylphenol, which is characterized by comprising the following steps: S1, carrying out nucleophilic addition reaction on 4-hydroxyacetophenone and a tetrahydrofuran solution of alkyl magnesium halide in a solvent 1 to obtain 4-(2-hydroxypropyl-2-yl) phenol; and S2, carrying out an elimination reaction on the 4-(2-hydroxypropyl-2-yl) phenol and beta zeolite in a solvent 2 to obtain the p-isopropenyl phenol. The preparation method provided by the invention only comprises two steps of reaction, is simple and efficient, is strong in atom economy, and is relatively high in yield and purity of the obtained target product; in addition, beta zeolite is used as a catalyst, is green and efficient, and can be recycled, so that the production cost is reduced, and the generation of solid wastes and acid-base wastewater is reduced; the two-step reaction and post-treatment conditions are mild, the operation is simple, and the method is suitable for industrial large-scale production.