615-18-9Relevant articles and documents
Method for preparing 2-chlorobenzoxazole and 2,6-dichlorobenzoxazole from o-aminophenol by taking solid triphosgene as chlorinating agent
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Paragraph 0028-0030, (2018/12/05)
The invention provides a method for preparing 2-chlorobenzoxazole and 2,6-dichlorobenzoxazole from o-aminophenol by taking solid triphosgene as a chlorinating agent. The method comprises the followingsteps: step 1, respectively preparing 2-benzoxazolone and 2-mercapto benzoxazole by taking the o-aminophenol as a raw material; step 2, preparing the 2-chlorobenzoxazole by taking the 2-mercapto benzoxazole as a raw material and the solid triphosgene as the chlorinating agent; step 3, preparing 6-chlorobenzoxazolone by taking TCCA and the 2-benzoxazolone as raw materials; step 4, preparing 2-mercapto-6-chlorobenzoxazole; step 5, preparing the 2,6-dichlorobenzoxazole by taking the 2-mercapto-6-chlorobenzoxazole as a raw material and the solid triphosgene as the chlorinating agent. The method provided by the invention is a brand-new preparation method, which has the advantages of less corrosion to equipment, high yield, less reaction time, mild reaction conditions, less by-products and reduced environmental pollution.
Method for preparing halogenated (hetero) aromatic hydrocarbons
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Paragraph 0065; 0066, (2018/03/24)
The invention relates to a method for preparing halogenated (hetero) aromatic hydrocarbons. The halogenated (hetero) aromatic hydrocarbons are prepared from cheap and easily available perfluorobutyl iodide, carbon tetrabromide and carbon tetrachloride as iodinated, brominated and chlorinated reagents respectively under the action of alkali catalysis (promotion). The method comprises the following steps: firstly, (hetero) aromatic hydrocarbons, a halogenated reagent and an inorganic base are placed in an organic solvent, stirred at room temperature and monitored with TLC until a substrate disappears, and the reaction is stopped; then, a reaction mixed solution is poured into water and extracted, an organic phase is dried, and the organic solvent is removed under reduced pressure; finally, silica-gel column chromatography is performed on a crude product, and a product is obtained. Purification can also be performed by recrystallization. The method has the advantages that the synthetic route is wide in substrate range, raw materials and reagents are cheap and easily available, operation is simple, conditions are mild, yield is high, energy consumption is reduced, the reaction route is safe, gram-grade preparation can be performed and the like.
Efficient transposition of the sandmeyer reaction from batch to continuous process
D'Attoma, Joseph,Camara, Titi,Brun, Pierre Louis,Robin, Yves,Bostyn, Stéphane,Buron, Frédéric,Routier, Sylvain
, p. 44 - 51 (2017/11/30)
The transposition of Sandmeyer chlorination from a batch to a safe continuous-flow process was investigated. Our initial approach was to develop a cascade method using flow chemistry which involved the generation of a diazonium salt and its quenching with copper chloride. To achieve this safe continuous process diazotation, a chemometric approach (Simplex method) was used and extrapolated to establish a fully continuous-flow method. The reaction scope was also examined via the synthesis of several (het)aryl chlorides. Validation and scale-up of the process were also performed. A higher productivity was obtained with increased safety.
