- Preparation method of 3, 4-dimethylpyrazole and phosphate thereof
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The invention discloses a preparation method of 3, 4-dimethylpyrazole and phosphate thereof, which comprises the following steps: S1. making 2-butanone react with formate at -10 to 50 DEG C in a reaction solvent under the condition of keeping alkaline by using an alkaline substance, carrying out extraction separation, adding an alkylation reagent, continuing the reaction to obtain a reaction solution, and carrying out post-treatment to obtain a solution of an alkene ether compound, and S2, making the alkene ether compound prepared in the step S1 react with hydrazine hydrate or hydrazine salt at the temperature of -10 to 60 DEG C after the pH value is adjusted to 2-9, adding the alkaline substance to adjust the pH value to 7-11 after the reaction is finished, and carrying out post-treatmentto obtain the 3, 4-dimethyl pyrazole. The preparation method disclosed by the invention has the remarkable advantages of cheap raw materials, simplicity and convenience in operation, high yield, simplicity in three-waste treatment, high product quality, capability of recycling the solvent and the like, and is suitable for industrial production.
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Paragraph 0054; 0057; 0059; 0062; 0064; 0067; 0069; 0072
(2021/02/06)
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- Method for preparing 3,4-dimethylpyrazole and phosphate and metal organic complex thereof
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The invention discloses a method for preparing 3,4-dimethylpyrazole and phosphate and metal organic complex thereof. The method for preparing the 3,4-dimethylpyrazole comprises the steps that (1) isoprene is in contact with water under the action of a catalyst to obtain methyl isopropyl ketone; (2) the methyl isopropyl ketone is in contact with hydrazine hydrate under the action of sulfuric acid and iodide to obtain the 3,4-dimethylpyrazole. The method for preparing the 3,4-dimethylpyrazole has the advantages that the isoprene is taken as a raw material, the preparation method is simple, and the yield and purity of the product are high.
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Paragraph 0091; 0094; 0095; 0096
(2019/05/02)
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- Method for preparing 3, 4-dimethylpyrazole and phosphate thereof
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The invention discloses a method for preparing 3, 4-dimethylpyrazole and phosphate thereof. The method for preparing the 3, 4-dimethylpyrazole includes the steps: (1) feeding 2-butanone, aldehyde andalkali solution into a microchannel reactor and performing aldehyde ketone condensation reaction to produce 4-hydroxy-3-methyl-2-butanone salt; (2) mixing reaction liquid obtained in the step (1) andacid liquid in the microchannel reactor to obtain 4-hydroxy-3-methyl-2-butanone water solution; (3) performing reaction on hydrazine hydrate and the 4-hydroxy-3-methyl-2-butanone water solution in themicrochannel reactor, mixing reaction liquid with the alkali solution and hydrogen peroxide, and performing oxidative dehydrogenation reaction to obtain 3, 4-dimethylpyrazole water solution; (4) performing organic extraction and distillation on the 3, 4-dimethylpyrazole water solution to obtain the 3, 4-dimethylpyrazole. According to the method, reaction time is greatly shortened, the yield and the purity of products are ensured, and continuous production can be realized.
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Paragraph 0101; 0107; 0117; 0120; 0124; 0125
(2019/04/17)
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- Preparation method of 3,4-dimethylpyrazole and preparation method of 3,4-dimethylpyrazole phosphate
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The invention discloses a preparation method of 3,4-dimethylpyrazole and a preparation method of 3,4-dimethylpyrazole phosphate. The methods comprise the following steps: performing condensation by using 2-butanone and formate as raw materials, performing aminolysis, performing cyclization to prepare the 3,4-dimethylpyrazole; and performing a salt forming reaction on the 3,4-dimethylpyrazole and phosphoric acid to obtain the 3,4-dimethylpyrazole phosphate. The preparation method of the 3,4-dimethylpyrazole and the preparation method of the 3,4-dimethylpyrazole phosphate provided by the invention have the significant advantages that the raw materials are cheap and easy to obtain, the operation is simple and convenient, the yield is high, the product quality is high, the solvent can be recovered and reused, and the methods are suitable for industrial production.
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Paragraph 0058; 0059
(2019/10/01)
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- Method for producing substituted pyrazoles
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Pyrazole derivatives are prepared by reacting carbonyl compounds R1—C(O)—CH(R2)—CH2R3with hydrazine, its hydrate or its salts in 30 to 100% by weight sulfuric acid in the presence of catalytic amounts of iodine or of an iodine compound.
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- Process for preparing pyrazoles
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A process for preparing pyrazoles of the formula I in which R1,R2,R3 independently of one another are C1- to C20-alkyl, C3- to C8-cycloalkyl, or C7- to C20-aralkyl or aryl, unsubstituted or substituted by C1- to C4-alkyl, halogen and/or nitro, R1,R3 are additionally independently of one another hydrogen, by reacting a carbonyl compound of the formula R1-CH2-CO-R2, in which R1 and R2 are as defined above in the presence of a strong base with a) formic esters of the formula H-COOR4, in which R4 is C1- to C8-alkyl at from (-20) to 70 DEG C. and a pressure of from 1 to 50 bar or b) carbon monoxide at from 0 to 100 DEG C. and a pressure of from 1.5 to 150 bar and reacting the resulting intermediate, the hydrazines of the formula R3-NH-NH2, in which R3 is as defined above, and an inorganic or organic acid at from 0 to 90 DEG C. and a pressure of from 1 to 10 bar, which comprises filtering off or centrifuging off the intermediate, is described.
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- Preparation of pyrazole and its derivatives
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A process for preparing pyrazole and its derivatives of the formula I STR1 where R1, R2, R3 and R4 are each hydrogen, halogen, nitro, carboxyl, sulfonyl or C-organic radicals, from alpha,beta-unsaturated carbonyl compounds of the formula II STR2 and hydrazine or hydrazine derivatives of the formula III wherein, initially without additional diluent, an alpha,beta-unsaturated carbonyl compound of the formula II is reacted with hydrazine or a hydrazine derivative of the formula III, and the resulting reaction mixture is reacted in another step with a mixture of sulfuric acid and iodine or a compound which liberates iodine or hydrogen iodide.
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- Unusual Amination by Cleavage of an Exocyclic C-N Linkage
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Synthesis of various 3-alkyl-2-(1-pyrazolyl)-4(3H)-quinazolinones (1a-g) and their amination with formamide under different reaction conditions are described.
- Ram, Vishnu J.,Kushwaha, Dinesh S.
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p. 697 - 699
(2007/10/02)
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- Thermal and Photochemical Reactions of Bicyclic Azoalkanes in Concentrated Sulfuric Acid
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Thermolysis of bicyclic azo compounds 1a-d in concentrated sulfuric acid affords ethylene (trapped as ethyl sulfate) and pyrazoles 3 in marked contrast to thermolysis of the nonprotonated azoalkanes, for which only loss of nitrogen (N2) is observed.
- Adam, Waldemar,Miranda, Miguel A.
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p. 5498 - 5500
(2007/10/02)
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