87-65-0Relevant articles and documents
Method for catalytically synthesizing dichlorophenol by adopting surfactant catalyst
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Paragraph 0032-0033; 0040-0041, (2020/06/09)
The invention belongs to the field of chemical synthesis, and particularly relates to a method for dichlorinating a phenolic substance, which directionally and selectively catalyzes substitution of C-H at an ortho-position and a para-position of phenolic hydroxyl by Cl atoms. The dichlorination method comprises the following steps: adding concentrated hydrochloric acid into a reactor, then addinga catalyst and a phenolic reactant, heating in an oil bath under violent stirring, and then adding a H2O2 aqueous solution with the mass percent concentration of 30-60%, and reacting for 2-26 hours and then ending the reaction, collecting an organic phase, and diluting with acetonitrile to prepare a sample for analysis. According to the dichlorination method disclosed by the invention, water is used as a reaction medium, so that the use of a traditional VOC organic solvent and heavy metals is avoided, and the method is safer and more environment-friendly. Meanwhile, the reaction conditions aremild, the operation is simple and convenient, the product yield is high, and the atom economy is high.
Reductive dehalogenation and dehalogenative sulfonation of phenols and heteroaromatics with sodium sulfite in an aqueous medium
Tomanová, Monika,Jedinák, Luká?,Canka?, Petr
supporting information, p. 2621 - 2628 (2019/06/03)
Prototropic tautomerism was used as a tool for the reductive dehalogenation of (hetero)aryl bromides and iodides, or dehalogenative sulfonation of (hetero)aryl chlorides and fluorides, using sodium sulfite as the sole reagent in an aqueous medium. This protocol does not require a metal or phase transfer catalyst and avoids using organic solvent as the reaction medium. This method is especially suitable for substrates that readily tautomerize (such as 2-or 4-halogenated aminophenols and 4-halogenated resorcinols), for which dehalogenation or sulfonation proceeds under mild reaction conditions (≤60 °C). As sodium sulfite is an inexpensive, safe, and environmentally less hazardous reagent, this method has at least three potential applications: (i) in the deprotection of halogens as protecting groups, using sodium sulfite as a reducing agent; (ii) in the sulfonation of aromatic halides under mild reaction conditions avoiding hazardous and corrosive reagents/solvents; and (iii) in the transformation of toxic halogenated aromatics into less harmful compounds.
Ammonium Salt-Catalyzed Highly Practical Ortho-Selective Monohalogenation and Phenylselenation of Phenols: Scope and Applications
Xiong, Xiaodong,Yeung, Ying-Yeung
, p. 4033 - 4043 (2018/05/22)
An ortho-selective ammonium chloride salt-catalyzed direct C-H monohalogenation of phenols and 1,1′-bi-2-naphthol (BINOL) with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) as the chlorinating agent has been developed. The catalyst loading was low (down to 0.01 mol %) and the reaction conditions were very mild. A wide range of substrates including BINOLs were compatible with this catalytic protocol. Chlorinated BINOLs are useful synthons for the synthesis of a wide range of unsymmetrical 3-aryl BINOLs that are not easily accessible. In addition, the same catalytic system can facilitate the ortho-selective selenylation of phenols.