- 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 0016; 0042; 0046-0051; 0052; 0056-0061; 0062; ...
(2021/08/14)
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- COMPOSITIONS AND METHODS FOR THE TREATMENT OF PERIODONTITIS AND RHEUMATOID ARTHRITIS
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The invention relates to the compounds of formula I or its pharmaceutical acceptable salts, as well as polymorphs, solvates, enantiomers, stereoisomers and hydrates thereof. The pharmaceutical compositions comprising an effective amount of compounds of formula I, and methods for the treatment of periodontitis and rheumatoid arthritis may be formulated for oral, buccal, rectal, topical, transdermal, transmucosal, intravenous, parenteral administration, syrup, or injection.
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Paragraph 0105; 0106
(2015/05/26)
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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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- Method for preparing chiral diphosphines
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The invention concerns a method for preparing a compound of formula (1) wherein: A represents naphthyl or phenyl optionally substituted; and Ar1, Ar2independently represent a saturated or aromatic carbocyclic group, optionally substituted.
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- Process for preparing malonate derivatives or beta -keto esters from epoxide derivatives
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A process for preparing a malonic acid monoester or β-ketoester from an epoxide includes the steps of reacting an epoxide with carbon monoxide and an alcohol in the presence of a catalytic amount of a cobalt compound and at least one promoter to produce a β-hydroxyester, separating the β-hydroxyester from the cobalt compound and the promoter, and oxidizing the β-hydroxyester to produce a malonic acid monoester or β-ketoester.
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- Asymmetric hydrogenation method of a ketonic compound and derivative
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The present invention relates to a process for the asymmetric hydrogenation of a ketonic compound and derivative. The invention relates to the use of optically active metal complexes as catalysts for the asymmetric hydrogenation of a ketonic compound and derivative. The process for the asymmetric hydrogenation of a ketonic compound and derivative is characterized in that the asymmetric hydrogenation of said compound is carried out in the presence of an effective amount of a metal complex comprising as ligand an optically active diphosphine corresponding to one of the following formulae: STR1
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- 4-Chloro-4-chloromethyloxetan-2-one and a process for its production
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The new compound 4-chloro-4-chloromethyloxetan-2-one can be prepared by reacting diketene with sulphuryl chloride under conditions in which free radicals are formed. The 4-chloro-4-chloromethyloxetan-2-one exhibits antimicrobial activity. It is also useful as an intermediate, for example for the production of pigments and dyestuffs.
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- Reactions of 4-Chloroacetoacetic Esters with Thioureas
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Several heterocyclic acetic acids and esters were synthesized by allowing the appropriate thiourea, ethylenethiourea or trimethylenethiourea to react with 4-chloroacetoacetic esters, followed by acid hydrolysis to the hydrochlorides of the free acids.Both esters and acids of 2-aminothiazole-4-acetic acid, 5,6-dihydroimidazothiazole-3-acetic acid and 6,7-dihydro-5H-thiazolopyrimidine-3-acetic acid were obtained.
- Campaigne, E.,Selby, T. P.
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p. 1255 - 1257
(2007/10/02)
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