- Preparation method of ethyl 4-chloroacetoacetate
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The invention discloses a preparation method of ethyl 4-chloroacetoacetate, which specifically comprises the following steps of: (1) chlorination: cooling dichloromethane for the first time, then adding acetyl ketene for cooling for the second time, then introducing chlorine gas, and keeping the temperature; (2) esterification: dropwise adding absolute ethyl alcohol, and keeping the temperature; (3) desolvation and deacidification: heating and distilling to remove dichloromethane and hydrogen chloride; and (4) rectification: rectifying and purifying to obtain the product. Acetyl ketene is used as a raw material, the raw material is low in cost and easy to obtain, the synthesis steps are simple, and the production cost is reduced; by optimizing the ratio of process materials, the selectivity of the product ethyl 4-chloroacetoacetate is improved, and the yield is increased; and through high-vacuum low-temperature distillation, the decomposition of the heat-sensitive product ethyl 4-chloroacetoacetate is effectively prevented, and the yield and the product quality are improved.
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Paragraph 0041-0044; 0051-0054; 0061-0064
(2021/08/06)
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- Preparation method of methyl 4-chloroacetoacetate
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The invention discloses a preparation method of methyl 4-chloroacetoacetate, which specifically comprises the following steps: (1) chlorination: cooling dichloromethane for the first time, then adding ketene dimer for cooling for the second time, then introducing chlorine gas, and keeping the temperature; (2) esterification: dropwise adding absolute methanol, and keeping the temperature; (3) desolvation and deacidification: heating and distilling to remove dichloromethane and hydrogen chloride; and (4) rectification: rectifying and purifying to obtain the product. The diketene is used as the raw material, the raw material is low in cost and easy to obtain, the synthesis steps are simple, and the production cost is reduced; by optimizing the ratio of process materials, the selectivity of the product ethyl 4-chloroacetoacetate is improved, and the yield is increased; through high-vacuum low-temperature distillation, the decomposition of a heat-sensitive product ethyl 4-chloroacetoacetate is effectively prevented, and the yield and the product quality are improved.
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Paragraph 0012; 0042-0045; 0052-0055; 0062-0065
(2021/08/14)
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- Continuous device and method for industrial production 4 - chloroacetoacetate
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The invention relates to an industrial production 4 - chloroacetoacetate continuous device and a method. The device and method can inhibit the generation of byproduct 2 - chloroacetoacetate and 4 - chloroacetoacetate in 2 - chloroacetoacetate crude product can be controlled below 0.15%. The yield of 4 - chloroacetoacetate can be improved, and the yield 4 - chloroacetoacetate can reach 97% or more. The continuous device and the method provided by the invention can be operated continuously, 4 - chloroacetoacetate can be industrially produced, and the continuous device has remarkable economic value.
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Paragraph 0024; 0040-0041; 0042-0043; 0044-0045; 0046-0047
(2021/11/06)
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- A 4-chloro-acetyl-acetic acid ethyl ester preparation method
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The invention relates to a preparation method of 4-chloracetyl ethyl acetate. The preparation method comprises the following steps: by taking diketene as an initial raw material, synthesizing a 4-chloracetyl ethyl acetate coarse product in two steps: chlorination and esterification; then, rectifying to obtain a finished product, and adding a stabilizer anhydrous cupric sulfate into the chlorination step, wherein the addition is 0.02-1wt% of diketene. Compared with the prior art, the preparation method provided by the invention has the advantages that 1, by adding the stabilizer anhydrous cupric sulfate, the production of a byproduct 2-chloracetyl ethyl acetate is reduced and the production of the byproduct 2-chloracetyl ethyl acetate in the 4-chloracetyl ethyl acetate coarse product can be controlled below 0.5%, so that the distill yield is greatly improved; 2, the yield of 2-chloracetyl ethyl acetate is over 94.5%, and the cost is greatly lowered.
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Paragraph 0025; 0026
(2016/10/09)
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- PREPARATION OF 3,5-DIOXO HEXANOATE ESTER IN TWO STEPS
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The invention discloses a method for the preparation of tert-butyl 6-chloro-3,5- dioxohexanoate from Meldrum's acid derivative and its use for the preparation of tert-butyl (4R,6S)-(6-hydroxymethyl-2,2-dimethyl-1,3-dioxan-4-yl)acetate(BHA), Rosuvastatin and Atorvastatin.
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Page/Page column 22
(2012/10/18)
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- Process for the production of 4-chloroacetyl chloride, 4-chloroacetic acid esters, amides and imides
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The invention relates to process for the continuous production of 4-chloroacetoacetyl chloride, comprising the steps of (a) feeding diketene and chlorine into a thin film reactor and (b) reacting the diketene and chlorine to obtain 4-chloroacetoacetyl chloride. The invention also relates to a process for the production of 4-chloroacetic acid ester, 4-chloroacetic acid amide or 4-chloroacetic acid imide from 4-chloroacetoacetyl chloride obtained according to the inventive process.
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Page/Page column 9; 10
(2012/11/13)
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- Study of thiazoline derivatives for the design of optimal fungicidal compounds using multiple linear regression (MLR)
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Rice blast is the most serious disease of rice due to its harmfulness and its world wide distribution. Magnaporthe grisea is the cause of rice blast disease and destroys rice enough to feed several tens of millions of people each year. Fungicides are commonly used to control rice blast. But M. grisea acquires resistance to chemical treatments by genetic mutations. 2-Phenylimino-1,3-thiazolines were proposed as a novel class of fungicides against M. grisea in the previous study. To develop compounds with a higher biological activity, a new series of 2-phenylimino-1,3-thiazolines was synthesized and its fungicidal activity was determined against M. grisea. The QSAR analysis was carried out on a series of 2-phenylimino-1,3-thiazolines. The QSAR results showed the dependence of fungicidal activity on the structural and physicochemical features of 2-phenylimino- 1,3-thiazolines. Our results could be used as guidelines for the study of the mode of action and further design of optimal fungicides. Copyright
- Han, Won Seok,Lee, Jin Kak,Lee, Jun-Seok,Hahn, Hoh-Gyu,Yoon, Chang No
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scheme or table
p. 1703 - 1706
(2012/08/07)
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- Exploration of novel 2-alkylimino-1,3-thiazolines: T-type calcium channel inhibitory activity
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We have developed combinatorial libraries of new 2-alkylimino-1,3- thiazolines with four diversity points, consisting of more than 500 compounds, in a parallel synthetic fashion. The synthetic strategy was based on the construction of a large library aimed at the discovery of new compounds with T-type calcium channel inhibitory activity through structure modifications of hit compound 2. The syntheses of the compounds of Chemset A with four diversity points were accomplished by the condensation of thioureas 5 with α-haloketones 6{1-66} having two diversity points each. A library of phthalimidyl 1,3-thiazolines 24 was synthesized to provide Chemset B, which allowed the introduction of other diversity points through the nucleophilic character of the amino nitrogen. A sublibrary, Chemset C, was constructed from the libraries of Chemset A and Chemset B by functionalization of the C-4 position of the 1,3-thiazoline ring. The products containing ester or acid groups at the C-4 position of the 1,3-thiazoline ring were used in amide synthesis to give a new sublibrary within Chemset C. Deprotection of the phthalimidyl moiety of 24 followed by the reaction with benzoyl chloride gave the corresponding sublibrary in Chemset C. Another sublibrary which includes secondary amino derivatives was obtained by reduction of the amide moiety or reductive amination of 23 with phenyl aldehyde. The selected compounds from the generated libraries were evaluated with respect to inhibition of T-type calcium channels, where some of them have exhibited promising activity.
- Han, Minsoo,Nam, Kee Dal,Shin, Dongyun,Jeong, Nakcheol,Hahn, Hoh-Gyu
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experimental part
p. 518 - 530
(2010/08/20)
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- NOVEL CRYSTAL OF 7- 2-(2-AMINOTHIAZOLE-4-YL)-2-HYDROXYIMINOA CETAMIDO-3-VINYL-3-CEPHEM-4-CARBOXYLIC ACID (SYN ISOMER) AND METHOD FOR PREPARATION THEREOF
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A novel crystal (B-type crystal) of 7-[2-(2-aminothiazol-4-yl)-2-hydroxyiminoacetamide-3-vinyl-3-cephem-4-carboxylic acid (a syn isomer), characterized in that it exhibits peaks at diffraction angles shown in the following Table 1, in its powder X ray diffraction pattern: This crystal is obtained by forming a crystal from a solution at a temperature of -5 to 5°C in an acidic state. The crystal is not bulky, exhibits good stability and good filterability, and is excellent in the solubility toward water, and thus can be prepared with case.
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Page/Page column 11
(2010/02/15)
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- Crystalline 7-(2-(2-aminothiazol-4-yl)-2-hydroxyiminoacetamido)-3-vinyl-3-cephem-4-carboxylic acid (syn isomer)
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The invention relates to crystalline 7-[2-(2-aminothiazol-4-yl)-2-hydroxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylic acid (syn isomer) useful as an antimicrobial agent.
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- 4-Benzothiazolyl phenyl azo dyes
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There are described azo compounds of the formula STR1 wherein K is an optionally quaternized basic group, X is the radical COOR, in which R is an alkyl group or a substituted or unsubstituted phenyl group, or X is the radical CONHR', in which R' is an alkyl group or a substituted or unsubstituted phenyl group; and wherein the benzene rings B and/or D can be further substituted; and the use thereof as dyes for the dyeing of textile materials, and particularly for the dyeing of paper of all types, especially bleached, lignin-free, unsized paper.
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- Method for the production of haloacetoacetic acids
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Haloacetoacetic acids of the formula wherein R1 represents chlorine or bromine and R2 and R3 each represents hydrogen, chlorine or bromine, are obtained by converting diketene into a chloro or bromo acetoacetic acid halide by means of chlorine or bromine at a temperature of from about -10° to -40°C, and the acetoacetic chloro or bromoacetoacetic acid halide is converted into the corresponding acid by hydrolysis with a stoichiometrically equivalent (or excess) quantity of water.
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