64 results about "Claisen condensation" patented technology

The invention relates to a synthesis method of celecoxib, which comprises the following specific steps of: 1, carrying out claisen condensation on p-methylacetophenone and trifluoroacetic acid ethyl esters in an aprotic organic solvent under the catalysis of alkali to obtain 1-(4-methylphenyl)-4,4,4-trifluoro-1,3-butanedione; and 2, reacting the obtained 1-(4-methylphenyl)-4,4,4-trifluoro-1,3-butanedione with sulfonamide-phenylhydrazine hydrochloride to obtain celecoxib, wherein in the step 1, the alkali for catalysis is selected from one or more of sodium hydride, potassium hydride, lithium hydride and calcium hydride. The synthesis method of celecoxib provided by the invention is easy to operate, high in yield, high in product purity and easy for industrial production.

The invention relates to a preparation method of beta-diketone; Claisen condensation reaction is adopted; the chemical general expression of the beta-diketone is R1COCH2COR2, wherein, R1 is C6-C12 alkyl, and R2 is phenyl or alkylphenyl; the method comprises the following steps: ester, phenyl ketone and partial solvent are pre-mixed for spare; a condensating agent and remaining solvent are added in a reactor, and the temperature is raised under nitrogen atmosphere; during the period when the temperature of the reactor is raised to the needed temperature of the condensation reaction, the pre-mixed material is dropwise added in the reactor for carrying out the condensation reaction with a system which is composed of the condensating agent and the remaining solvent under an infinite reflux condition; after the pre-mixed material is dropwise added, heat-preserving condensation reaction is carried out continuously under the infinite reflux condition. The ester and the condensating agent in the raw material are contacted when the reacting condition is achieved, and acylation reaction is slow reaction, relative to the Claisen condensation reaction, thus being capable of better solving the acidylation problem of the ester, and reducing the effect of the acylation reaction to the minimum; the yield of the beta-diketone is more than or equal to 90 percent.

The invention discloses a fluorescent probe capable of quickly detecting hydrogen sulfite ions and a preparation method and application thereof. The preparation method includes: taking beta-pinene oxidation derivative nopinone which is one of main ingredients of natural renewable natural resource turpentine as a raw material, and allowing Claisen condensation reaction with 4-methyl bromobenzoate to obtain 3-(4'-bromobenzoyl) nopinone; allowing 3-(4'-bromobenzoyl) nopinone to be in coupling reaction with 4-formylbenzeneboronic acid to obtain 3-(4''-formyl-1', 1''-biphenyl-4'-carbonyl) nopinone;allowing 3-(4''-formyl-1', 1''-biphenyl-4'-carbonyl) nopinone to react with boron trifluoride etherate to obtain a 3-(4''-formyl-1', 1''-biphenyl-4'-carbonyl) nopinone based fluoroboron complex. Thecompound serving as a high-selectivity high-sensitivity color ratio type fluorescent probe has good application in the aspect of detecting the hydrogen sulfite ions.

The invention relates to a method for synthesizing a 4,4-dimethoxy-2-butanone fine chemical engineering raw material. The method comprises the following steps of: performing a Claisen condensation reaction of ethyl formate, liquid sodium methoxide, acetone and concentrated sulfuric acid, which serve as raw materials, to prepare butanone sodium enolate, dripping solution of the treated butanone sodium enolate into solution of methanol containing the concentrated sulfuric acid and reacting to obtain a crude product of the 4,4-dimethoxy-2-butanone, and distilling under normal pressure and reduced pressure to obtain the 4,4-dimethoxy-2-butanone. In the invention, the raw materials are cheap, and the method and process are simple, convenient to operate and suitable for large-scale industrial production and have a high industrial application value.

The invention provides a method for continuous production of dimethyl succinylo succinate. The technical scheme employs continuous drip adding to carry out Claisen condensation reaction on dimethyl succinate and sodium methoxide and Dieckmann condensation reaction, and can realize continuous discharge, after a certain product is collected, and then dilute sulfuric acid acidification is carried out to obtain dimethyl succinylo succinate. The method provided by the invention is designed based on classical experimental principles, and the operation mode is improved to form a brand-new technological process. The technical scheme shortens the reaction time, also reduces energy consumption, significantly improves the production efficiency, and at the same time overcomes the problem of large quality difference between different batches in batch production. The method provided by the invention takes innovative technological improvement and achieves good technical effect, simultaneously has the characteristics of low cost and easy realization, thus having good popularization prospect.

The invention discloses a preparation method of triethylene glycol di-2-ethylhexoate and relates to a method for preparing a plasticizer from triethylene glycol and isocaprylic acid serving as initial raw materials through processes such as Claisen condensation reaction, neutralization and distillation. The preparation method comprises the steps of adding isocaprylic acid and triethylene glycol serving as the raw materials into a reactor, stirring while heating to dissolve isocaprylic acid and triethylene glycol, keeping the temperature at 40-80 DEG C, and adding an adsorbent and a catalyst; reacting under the conditions that the temperature is 80-110 DEG C and the vacuum degree is 1-15mmHg, then, cooling, and dropwise adding a sodium hydroxide water solution with the concentration of 1-2.5%; and then, adding a decolorizing agent, distilling under the conditions that the temperature is 80-150 DEG C and the vacuum degree is 0.5-1mmHg, and filtering to obtain triethylene glycol di-2-ethylhexoate. The preparation method disclosed by the invention is simple and is easily implemented. The preparation method has the characteristics that raw materials are available, and negative pressure and low-temperature reaction is adopted, so that the production cost is greatly reduced. In addition, an adsorbent is added to inhibit side reaction and adsorb colored impurities, so that the quality of triethylene glycol di-2-ethylhexoate is improved, and the heat resistance of triethylene glycol di-2-ethylhexoate is greatly improved. The prepared triethylene glycol di-2-ethylhexoate has the chroma of less than 30 which is superior to the chroma of a domestic product (more than 50) if being detected after being heated at the temperature 180 DEG C for 2 hours. Problems existing in the existing production method are solved.

The invention discloses nopinic alkyl beta-dione boron difluoride complexes and a preparation method and application thereof. The natural reusable resource beta-pinene oxidation product, namely nopinone, is used as a raw material to prepare novel nopinic alkyl beta-dione boron difluoride complexes 3a and 3b; nopinone is subjected to Claisen condensation with methyl p-methoxybenzoate 1a and methyl4-bromobenzoate 1b to separately obtain nopinic alkyl beta-dione compounds 2a and 2b; the compounds 2a and 2 b are subjected to complexing with boron trifluoride etherate to separately obtain nopinicalkyl beta-dione boron difluoride complexes 3a and 3b. The nopinic alkyl beta-dione boron difluoride complexes 3a and 3b have good fluorescent performance and high fluorescent quantum yield; an electroluminescent device made with the nopinic alkyl beta-dione boron difluoride complexes can emit blue-green light. It is shown that the nopinic alkyl beta-dione boron difluoride complexes as light-emitting materials have good application value in the preparation of electroluminescent devices.

A continuous process for producing compounds having the general formula (6) is provided:

wherein R is a straight or branched chain alkyl group, R¹ is a straight or branched chain alkyl group substituted with a nitrile group, a hydroxy group or a halogen atom, R² is a hydroxy group or a keto group, and each R³ is, independently, hydrogen or a straight or branched chain alkyl group, comprising providing a continuous stream of an alkyl acetate and a continuous stream of an alkali metal or alkaline earth metal amide base and contacting the continuous streams to yield an enolate compound, providing a continuous stream of a compound of formula (5):

wherein R¹ is as previously defined, and contacting the continuous stream of compound (5) with a continuous stream of the enolate above 20° C. to yield an intermediate compound and treating the intermediate compound with an acid.

The invention discloses a method for preparing ethyl 4,4-difluoroacetoacetate. The method comprises the following step: by taking ethyl difluoroacetate and ethyl acetate as raw materials, and an ethanol solution of sodium ethoxide as a catalyst, in the presence of an organic solvent, carrying out a Claisen condensation reaction, thereby obtaining the ethyl 4,4-difluoroacetoacetate. The method disclosed by the invention has the characteristics of being gentle in reaction condition, high in security, good in reaction selectivity, easy in product separation and purification, applicable to industrial production, and the like.

The present invention provides a process for producing a muscone represented by (1) by subjecting a citronellic acid derivative and an undecenoate to a Claisen condensation reaction to produce a keto ester compound represented by (2) decarboxylating the keto ester compound to produce 2,6-dimethyl-8-oxy-2,17-heptadecadiene, cyclizing the heptadecadiene using a metathesis catalyst to produce a 6-dehydromuscone represented by (3) and then hydrogenating the double bond. The present invention also provides the keto ester compound.

The invention belongs to the field of drug synthesis, and particularly relates to a preparation method of a tolvaptan intermediate 7-chloro-2,3,4,5,10,11-hexahydro-1H-1-benzodiazepines-5-one. The method comprises the following steps: by taking N-vinylpyrrolidone as an active ingredient, rearranging under light to obtain 4-azecycloheptatrienone, then protecting nitrogen methyl p-toluenesulfinate, reacting with 2-chloro-2-butenal in the presence of diaryl D-prolinol derivatives to generate 7-chloro-2,3,4,5,10,11-hexahydro-1H-1-benzodiazepines-5-one, dehydrogenizing and aromatizing in the presence of manganese dioxide, and finally removing protection groups to obtain the 7-chloro-2,3,4,5,10,11-hexahydro-1H-1-benzodiazepines-5-one. Due to no Claisen condensation or Friedle-Crafts reaction in the conventional synthesis method, the potassium tert-butanol and aluminum trichloride are omitted, the preparation method is mild in reaction conditions, easily available in raw materials, capable of lowering the cost, and more suitable for industrial production.

The invention discloses a pino alkyl indazole aluminum ion fluorescence probe, a preparation method and an application thereof. The preparation method comprises the following steps: taking a natural regenerated resource beta-pinene derivative nopinone as a raw material; carrying out claisen condensation reaction between nopinone and 2-pyridine methyl formate, thereby acquiring 3-(2'-pyridine formyl) nopinone; cyclizing 3-(2'-pyridine formyl) nopinone and hydrazine hydrate, thereby acquiring a pino alkyl indazole compound 6,6-dimethyl-3-(2'-pyridyl)-4,5,6,7-tetralin-2H-5,7-bridge methylene indazole. The compound as a fluorescence probe with high selectivity and sensitivity has an excellent application in detecting aluminum ions in food.

The invention relates to the technical field of organic synthesis, in particular to a preparation method of 4-ethylpyridine. The preparation method of the 4-ethylpyridine comprises the following stepsof: mixing ethyl 4-picolinate with sodium ethoxide, heating to 90 to 110 DEG C, then dropwise adding ethyl acetate, and carrying out claisen condensation reaction, thus obtaining ethyl 3-oxo-3-(4-pyridyl) propionate; mixing the ethyl 3-oxo-3-(4-pyridyl) propionate, dimethyl sulfoxide and water, and carrying out heating treatment, thus obtaining 4-acetylpyridine; cooling after mixing glycol with potassium hydroxide, adding hydrazine hydrate, rising the temperature to 60 to 80 DEG C, then mixing with the 4-acetylpyridine, and carrying out reduction reaction, thus obtaining the 4-ethylpyridine.The 4-ethylpyridine prepared through the preparation method provided by the invention is higher in yield and purity.

The invention relates to a preparative method of 2, 6-diacetylpyridine. By adopting alkali metal or alkaline earth metal as the alkaline reagent, the method carries out the Claisen condensation to 2, 6-pyridine dicarboxylic aid diethyl ester and ethyl acetate to gain the 2, 6-diacetylpyridine. Specifying in the formulate on the right, compared with other methods, the method provided in the invention needs not to conduct special treatment for the reaction raw materials and the alkaline reagents. The minor water or ethanol in the reaction system has no distinct influence to the reaction, and the reaction system cancels drying and purifying treatment in order to simplify the experimental operation, reduce the reaction period, save cost, improve the output rate of the product and demonstrate good applicable valve.

The invention discloses a method for preparing baicalein. According to the method, 2,6-dimethoxy-p-benzoquinone used as an initial raw material is subjected to reduction, Friedel-Crafts acetylation, claisen condensation, dehydrogenation oxidation cyclization and demethylation five reactions to obtain baicalein with high yield. The method uses low-price and easily-available initial raw material, reagent and the like, has few synthesizing steps, is easy and convenient to operate and easy for production control, has high product yield and high purity, and is suitable for large-scale preparation and production application of baicalein.

The invention discloses a nopinalkyl indazole silver ion fluorescence probe and a preparation method thereof. Beta-pinene derivative nopinone which is a natural renewable resource is used as a raw material, nopinone is subjected to a Claisen condensation reaction with methyl pyridine-2-carboxylate, and 3-(2'-pyridyl formyl) nopinone is prepared; and 3-(2'-pyridyl formyl) nopinone is subjected to condensation cyclization with phenylhydrazine, and a nopinalkyl indazole compound 6,6-dimethyl-2-phenyl-3-(2'-pyridyl)-4,5,6,7-tetrahydro-2H-5,7-endomethylene indazole is obtained. The compound as a specific fluorescence probe molecule has good application in the aspect of silver ion detection.