Study on the Halogen Atoms Participation in Radical Reaction

Bromination reaction is a low atom economy reaction because of the byproduct of HBr with general bromide reagent. It was an effective measure to improve the atom economy of this reaction though oxidation bromide. HBr-H₂O₂ is a green reagent of the bromination reaction in which there is no organic waste liquid and inorganic waste acid. The activation of C–H bond of alkanes though oxidative bromination was the studied in the paper.The bromination reaction of alkanes and the side chain of arene used with H₂O₂ as oxidant was studied in HBr-H₂O₂ system. For alkane, cyclohexane was chosen as the model reactant. The catalyst、the amount of H₂O₂ and light were discussed. The results showed that the optimal parameters were as follows: the ratio of HBr: H₂O₂ 1:1.5, the reaction temperature was the b.p of alkane or 80℃and 4 % the diatomite as catalyst, light with 60 W incandescent light bulb , the yield was 80.1%. Under the same condition, the bromide reaction of cyclopentane, heptane, hexane, heptane, octane, nonane and methyl cyclohexane were investigated with the system of HBr-H₂O₂.For the side chain of arene, 3-chloro-toluene was used as a model reactant. The optimal condition of light, catalyst, temperature, molar ration of reactants was selected experimentally as follows: the ratio substrate: HBr: H₂O₂ =1:1.25:1.25, 0℃, light with 60 W incandescent light bulb. The yield of benzyl bromide was 61%. Under the same condition, the bromination reaction of toluene with electron donor groups and electron withdrawing group were investigated with the system of HBr-H₂O₂. The bromination reaction of thiophene can get mono- and di- products. The results showed that the optimal parameters of 2-bromthiophene were as follows: the ratio of thiophene : HBr : H₂O₂ 1:1.0:1.5, the reaction temperature was -5℃and no light , the yield was 85%. The results showed that the optimal parameters of 2, 5-dibromthiophene were as follows: the ratio of thiophene : HBr : H₂O₂ 1:2.5:3, the reaction temperature was 0℃and no light , the yield was 97.4%.2-amino-1, 4- anphthoquinone have a wide range of drug activity andindustrial application. Paper in second part research the reaction of anphthoquinone with amino acid ester . It found a new method of synthesis 2-amino-1, 4- anphthoquinone.Amino acid ester and anphthoquinone was used as a model reactant. The reaction was performed in CH2Cl2 at room temperature by using NaHCO₃, I2 and N₂. The results showed that the optimal parameters were as follows: the ratio of substrate: anphthoquinone: amino acid ester: NaHCO₃: I₂ =1:3:3:1.The reaction also performed in high temperature and light with 220 W high-pressure mercury lamp.The reaction also performed in CHCl3 with pyridine and 220 W high-pressure mercury lamp to get -methylaminoanphthoquinone,the yield is 55.8%.The reaction also performed in CH₃CN at 80℃by using NaHCO₃/I₂ to get a new compounds,which has a pyrrole ring,the yield is 78%。