7283-96-7Relevant articles and documents
Low cost preparation method of high purity 5-chlorothiophene-2-formyl chloride
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Paragraph 0047-0055; 0072-0077, (2019/03/26)
The invention relates to a low cost preparation method of high purity 5-chlorothiophene-2-formyl chloride. According to the preparation method, 2-chlorothiophene and a formylation reagent carry out reactions to generate 5-chlorothiophene-2-formaldehyde, then 5-chlorothiophene-2-formaldehyde is oxidized by an oxidant to generate 5-chlorothiophene-2-formic acid, and finally 5-chlorothiophene-2-formic acid and an acyl-chlorination reagent carry out acyl-chlorination reactions to generate 5-chlorothiophene-2-formyl chloride. 5-chlorothiophene-2-formyl chloride can be used as a key intermediate inrivaroxaban preparation. The preparation method has the advantages of cheap and easily-available raw materials, simple technical route, low raw material cost, little discharge amount of wastewater, low salt content of wastewater, environmental friendliness, and high reaction selectivity. The purity of obtained 5-chlorothiophene-2-formyl chloride is high, and the industrial production of high purity rivaroxaban is promoted.
Method for preparing 5-chlorothiophene-2-carboxylic acid through one-pot synthesis
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Paragraph 0027-0028; 0030-0031, (2018/12/13)
The invention relates to a method for preparing 5-chlorothiophene-2-carboxylic acid through one-pot synthesis. The method comprises the following steps: leading or adding a chlorinated reagent into 2-thiophenecarboxaldehyde for heat insulation reaction, so as to obtain an intermediate 5-chlorine2-thiophenecarboxaldehyde after the reaction is completed, wherein the intermediate 5-chlorine2-thiophenecarboxaldehyde is directly used for the next reaction without separation; slowly dropping the intermediate 5-chlorine2-thiophenecarboxaldehyde into pre-cooled caustic soda liquid, controlling the reaction temperature to be not higher than 30 DEG C, cooling after the dropping is completed, slowly leading chlorine into the pre-cooled caustic soda liquid for heat insulation reaction after the leading of the chlorine is completed, cooling to 5 DEG C after a center control reaction is completed, adding sodium sulfite for quenching, adding a solvent for extraction and impurities elimination, regulating the pH value of a water phase with concentrated hydrochloric acid, performing suction filtration, recrystallizing a filter cake, and drying, so as to obtain an target compound. According to the method, the defects of the prior art of being high in raw materials, complex in operation and more in three wastes are overcome; the provided method for synthesizing 5-chlorothiophene-2-carboxylic acidis suitable for industrial production.
Sodium hypochlorite pentahydrate (NaOCl·5H2O) crystals; An effective re-oxidant for TEMPO oxidation
Okada, Tomohide,Asawa, Tomotake,Sugiyama, Yukihiro,Iwai, Toshiaki,Kirihara, Masayuki,Kimura, Yoshikazu
, p. 2818 - 2827 (2016/05/19)
The novel oxidant of sodium hypochlorite pentahydrate (NaOCl·5H2O), which is now available for industrial and laboratory use has several advantageous properties. The crystalline material has 44% of NaOCl, contains minimal sodium hydroxide and sodium chloride, and the aqueous solution indicates pH 11-12. Herein, NaOCl·5H2O crystals are examined for use as an oxidant for primary and secondary alcohols, with or without nitroxyl radicals, in the presence or absence of phase-transfer catalysts. The pentahydrate crystals alone (without nitroxyl radicals) demonstrate a powerful oxidizing ability, converting secondary alcohols to the corresponding ketones. In the presence of TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl) or 1-Me-AZADO (1-methyl-2-azaadamantane N-oxy radical), sterically hindered secondary alcohols are oxidized without pH adjustment. A proposed mechanism for the oxidation is discussed.