79results about How to "Reduce difficulty of reaction" patented technology

The invention relates to a method for synthesizing trans-(1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine which is an intermediate for preparing an anticoagulation medicine Ticagrelor. The method provided by the invention mainly comprises the following steps of: synthesizing the trans-(1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine protected by tertiarybutoxy carbonyl through carrying out a rearrangement reaction of DPPA (Diphenylphosphoryl Azide); then removing the protective group of the trans-(1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine protected by the tertiarybutoxy carbonyl and then alkalifying to obtain the product. The whole reaction can be finished through a one-pot boiling synthetic method so that synthesizing steps and synthesizing time are greatly saved, the cost is effectively reduced and the yield is improved; and the method for synthesizing the trans-(1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine has the very active meaning in the industrial production.

The invention belongs to the technical field of chemical engineering and relates to a solid chlorine dioxide effervescent tablet and a preparation method thereof. The solid chlorine dioxide effervescent tablet is prepared from the following raw materials in parts by weight: 8-30 parts of chlorine dioxide matrix, 5-20 parts of halogen source, 0.5-2 parts of cladding passivant, 0-5 parts of corrosion inhibitor, 25-60 parts of acidifier, 0-2 parts of surfactant, 15-24 parts of drying agent and an effervescing agent. By adopting the solid chlorine dioxide effervescent tablet and the preparation method thereof, the safety and the stability of a product and the yield of chlorine dioxide are obviously improved. In the solid chlorine dioxide effervescent tablet and the preparation method thereof,fine chloride is adopted to serve as halogen source, and malic acid is adopted to serve as the the acidifier, thereby, the sediment of calcium salt is avoided, and the corrosivity of the solution of the calcium salt is reduced. Moreover, the safe reliability of the product applied to disinfecting foods and drinking water is ensured.

The invention discloses a preparing method for polycarboxylate-type anti-mud water reducer with a modified side chain terminal group. The preparing method includes the steps that azido-terminated polycarboxylate-type water reducer is prepared first, and then the azido-terminated polycarboxylate-type water reducer and an alkyne-terminated benzene-pyridine derivative are subjected to a click chemical reaction to prepare the polycarboxylate-type anti-mud water reducer with the side chain terminal group being the alkyne-terminated benzene-pyridine derivative. As the terminal hydroxyl group of the polycarboxylate-type water reducer is modified into a five-membered ring and a benzene/pyridine ring, the physical size of the side chain terminal of the polycarboxylate-type water reducer is greatly increased, and the polycarboxylate-type water reducer is not prone to be inserted into a layered structure of clay to achieve the anti-mud effect without affecting the inherent functions. The technical problems that as a side chain of existing polycarboxylate-type water reducer is prone to be inserted into the layered structure of the clay, the polycarboxylate-type water reducer is lost fast, and then the work performance of concrete is lowered are solved.

The invention discloses a method for synthesizing 2,6-dimethyl phenoxyacetic acid, comprising the following steps of: (1) adding 2,6-dimethyl phenol to an alkali aqueous solution, wherein the 2,6-dimethyl phenol and alkali are added in the mole ratio of 0.5-1.0:1.0; (2) stirring to dissolve the mixture, then filtering after sufficient reaction, increasing the temperature of a filtering material and dewatering to obtain 2,6-dimethyl phenolate; (3) mixing the 2,6-dimethyl phenolate and chloroacetic acid in the mole ratio of 0.5-1.0:1.0, heating till the 2,6-dimethyl phenolate and the chloroacetic acid are completely melted, and reacting in an inert gas atmosphere; (4) after the reaction is finished, cooling to room temperature, adding water or alkali liquor for washing, and filtering to obtain a crude product; and (5) recrystallizing the crude product to obtain a 2,6-dimethyl phenoxyacetic acid pure product. The synthesizing method has the advantages of simple and convenient operation, short reaction time, easy postprocessing, few side product, high productivity, and the like.

The invention discloses a preparation method of apremilast (+)-2-[1-(3-ethoxy-4-methoxyphenyl)-2-mesylethyl]-4-acetamidoisoindolinyl-1,3-dione. The method comprises the following steps: (1) converting a compound 1-(3-ethoxy-4-methoxyphenyl)-2-(methanesulfonyl)ethylamine racemate disclosed as Formula (II) into a salification substance disclosed as Formula (III) by using a resolving agent; and (2) connecting the compound disclosed as Formula (III) with 3-acetamidophthalic anhydride to obtain the compound disclosed as Formula (I). The method can be utilized to obtain the stable apremilast acceptable finished product, has the advantages of mild technological conditions, simple after-treatment, high purity and low reaction cost, and can easily implement industrial production.

The invention relates to a preparation method of high-flowability positive ion modified copolyester. Binary acid I, dihydric alcohol I and high-flowability branched structure modifiers are uniformly mixed and then subjected to esterification reaction, and isophthalic acid-5-sodium sulfonate and dihydric alcohol II esterification products are led in after esterification reaction and subjected to pre-condensation reaction and final polycondensation reaction to prepare the high-flowability positive ion modified copolyester. The high-flowability branched structure modifiers are more than one of pyromellitic anhydride, cyclopentane tetracarboxylic anhydride, benzophenone tetracarboxylic dianhydride, trimellitic anhydride, mellophanic dianhydride, pyromellitic acid, cyclopentane tetracid, benzophenone tetracid, trimellitic acid and mellophanic acid, and the dihydric alcohol II is more than one of butanediol, pentanediol, hexanediol, heptanediol, octylene glycol, nonanediol and decanediol. Two modified components are introduced, so that flow-activation energy is remarkably reduced, acting force of the copolyester and tube walls in the flowing process is reduced, and melt viscosity loss iseffectively controlled.

The invention discloses a preparation method of alpha-crystal form imatinib mesylate. The preparation method comprises the following steps that 1, 4-[(4-methyl piperazine-1-yl)methyl]benzoic acid dihydrochloride shown in the formula II is converted into an acyl chloride shown in the formula III by an acylating chlorination reagent; 2, the acyl chloride shown in the formula III and N-(5-amino-2-methylphenyl)-4-(3-pyridyl)-2-aminopyrimidin undergo a condensation reaction in the presence of an alkali to produce a compound shown in the formula IV; and 3, the compound shown in the formula IV and methylsulfonic acid undergo a salt forming reaction in the presence of an organic solvent to produce a compound shown in the formula I. The preparation method can realize preparation of stable alpha-crystal form imatinib mesylate and allows mild process conditions. The stable alpha-crystal form imatinib mesylate can be after-treated simply and has high purity. The preparation method has a low reaction cost and is suitable for industrial production.

This invention relates to a preparation of cellulose membrane which is no pollution,low cost and naturally degradable,by the method of surface activation about cellulose by using hypothermic plasmas body to administer radiation and dissolving cellulose by using dilute alkali solution. The prepared cellulose membrane can be used in the area of packaging and printing.

The invention discloses a preparation method of maleic anhydride grafted vegetable oil acid. The preparation method is characterized by comprising steps as follows: vegetable oil acid, maleic anhydride, a catalyst and a solvent are added into a reaction kettle and heated for an Alder-Ene reaction, unreacted raw materials and solvent are boiled off through pressure reduction after the reaction, and the maleic anhydride grafted vegetable oil acid is obtained. The preparation method is simple in process, raw materials are safe, non-toxic, easy to obtain and low in cost, the conditions are mild, and the obtained product is light in color and can be used for the next step, so that the industrialized implementation is facilitated.

A method for refining an organic composition containing 4-aminodiphenylamine, aniline, azobenzene, and phenazine, having the steps of feeding the organic composition to a first rectification column, producing a first effluent composition containing aniline, azobenzene, phenazine, and a small amount of 4-aminodiphenylamine at the top of the first rectification column and a second effluent composition containing crude 4-aminodiphenylamine at the bottom of the first rectification column, feeding the second effluent composition to a second rectification column, and producing a 4-aminodiphenylamine composition at the top of the second rectification column and a residual composition at the bottom of the second rectification column.

The invention discloses a preparation method of new crystal form tapentadol hydrochloride, which comprises the following steps of (1) converting (2R, 3R)-3-(3-methoxyphenyl)-N,N,2-trimethyl-amylamine hydrochloride by use of a demethylation reagent into the formula (III): (-)-(1R, 2R)-3-(3-dimethylamino-1-ethyl-2-methylphenyl)phenol; (2) salifying the compound of formula (III) with hydrochloric acid in a mixed solvent of acetonitrile and isopropyl alcohol to obtain a compound of formula (I): (-)-(1R, 2R)-3-(3-dimethylamino-1-ethyl-2-methylphenyl)phenol hydrochloride. By adopting the method disclosed by the invention, stable new crystal form tapentadol hydrochloride can be obtained; moreover, the process conditions are mild, the after-treatment is simple, the purity is high, the reaction cost is low, and industrial production is easy to realize.

The invention belongs to the field of synthetic drugs and particularly relates to a preparation method of tofacitinib citrate. The preparation method comprises the following steps: (1) adding a compound I into hydroiodic acid to obtain a compound II; (2) dissolving the compound II in a solvent, and adding a base to obtain a compound IV; and (3) reacting the compound IV and the compound II to obtain a compound V, namely, tofacitinib citrate, wherein the compound I, the compound II, the compound III, the compound IV and the compound V have molecular structures as shown in the description. By the preparation method, the reaction time is greatly shortened, the post-treatment is simplified and the cost is reduced.

The invention provides a preparation method of high-molecular-weight polylactic acid. The method comprises the following steps: prepolymerization, polymerization, chain extension and crosslinking, wherein a chain extender in the crosslinking step is a dioxazoline chain extender, and a crosslinking agent in the crosslinking step is a polycarboxyl compound. According to the invention, the polycarboxyl compound is used for enabling polylactic acid molecules to react so as to form a net-shaped cross-linked structure, so the molecular weight of polylactic acid is further increased, and the mechanical properties of polylactic acid are improved; meanwhile, it is unexpectedly found that a synergistic effect exists between the used dioxazoline chain extender and the polycarboxyl compound added in the crosslinking step, the molecular weight of the polylactic acid can be increased by adjusting the proportion of the dioxazoline chain extender to the polycarboxyl compound, and the color and lusterof the produced polylactic acid are not affected by chain extension and crosslinking.; moreover, activated clay added in the pre-polymerization step is found to have effect on improving the impact resistance of the polylactic acid, reducing reaction difficulty and further improving the weight-average molecular weight of the polylactic acid.

The invention discloses a synthetic method of 3-bromo-5-(2-ethylimidazo[1,2-a]pyridine-3-carbonyl)-2-hydroxybenzonitrile, particularly relates to a synthetic method of a compound shown as a formula (III), and particularly relates to a step A or a step B; the preparation method comprises the following steps: A, heating a compound shown as a formula (I) and a compound shown as a formula (II) in an organic solvent for reaction, and heating an obtained reaction product and alkali in the presence of water for continuous reaction to obtain a compound shown as a formula (III); and B, heating the compound shown as the formula (I), a compound shown as a formula (II) and alkali in an organic solvent to react, and heating an obtained reaction product in the presence of water to continuously react toobtain a compound shown as a formula (III).

The present invention discloses a preparation method of a polycarboxylate superplasticizer with carbon dioxide, comprising the following steps: (1) preparing a polycarboxylate superplasticizer prepolymer: performing an oxidation-reduction radical polymerization of an unsaturated macromonomer, an unsaturated phenol derivative, a reducing agent, an initiator and a chain transfer agent with different proportions under a nitrogen atmosphere to obtain a novel polycarboxylate superplasticizer prepolymer with different molecular weight; adjusting the pH by adding an alkali; (2) preparing a polycarboxylate superplasticizer: performing a Koble-Schmitt reaction between the polycarboxylate superplasticizer prepolymer and a carbon dioxide for a certain time to obtain the polycarboxylate superplasticizer. The polycarboxylate superplasticizer prepared by the method of the present invention retains the advantages of the existing water-reducing admixture of the polyether monomer compounds, and the production process is simple, safe, controllable, less side effect and has a better cost effective and competitive advantage.