The Study On Product-selectivity Control In The Reaction Of 2-Halobenzonitrile And Metal Sulfide

2-Halobenzonitrile and its derivatives that have dual reaction sites(nitrile and halogen)are used broadly in organic synthesis,which have attracted much attention.The halo group of 2-halobenzonitrile is liable to be substituted by nucleophilic reagents due to the strong electron withdrawing of cyano group in the benzene ring.While the cyano group could also react with all kind of nucleophilic reagents.Therefore,the dual reaction sites of 2-halobenzonitrile would competitively react with nucleophilic reagents.The reaction of metal sulfide with the dual reaction sites of 2-halobenzonitrile are synthesized 2-mercaptobenzonitrile or 2-halothiobenzamide.The 3H-1,2-benzodithiole-3-thione is synthesized by dual reaction sites react together.In this paper,the reaction selectivity of metal sulfide and 2-halobenzonitrile was studied.Concrete research investigated were as follows.1.A versatile method for the synthesis of 2-halothiobenzamide was established by the reaction of sodium hydrosulfide with 2-halobenzonitrile.It was found that magnesium chloride was acidic in the model,which helped the reaction of 2-halobenzonitrile and sodium hydrosulfide to synthesize 2-halothiobenzamide.2.At 70?,the method of synthesizing 2-mercaptobenzonitrile was established by the nucleophilic substitution reaction of sodium sulfide and halogen of the 2-halobenzonitrile.The yield of 2-fluorobenzonitrile was higher and the other halogen-substituted were lower in the reaction solution.3.Under the action of CO2,sodium hydrosulfide reacts with the dual reaction sites of 2-iodobenzonitrile in the presence of cuprous iodide,which established a new method for the synthesis of 3H-1,2-benzodithiole-3-thione.The role of acid catalysis of CO2 be similar to magnesium chloride in the system.4..For a initial discovery,Hydrogen proton is key factor of selective control of the synthesis of 2-mercaptobenzonitrile or 2-halothiobenzamide in the reaction system.When it contains hydrogen protons in the reaction system of the 2-halobenzonitrile and the metal sulfide,2-halothiobenzamide is mainly produced,otherwise,mainly the 2-mercapto-benzonitrile.