The Synthesis Of9,10-phenanthrenequinones Via Intramolecular Coupling Of2-acetyl-biphenyls

9,10-Phenanthrenequinones are the oxidative products of phenanthrenes. They areimportant intermediate with extensive application in the field of pesticides, medicine,dye, photoelectric and so on. Scientists also have done many research on the synthesisof9,10-phenanthrenequinones. In this paper, we describe a simple method of preparingunsymmetrical9,10-phenanthrenequinones through intramolecular coupling of2-acetyl-biphenyls rather than the common oxidation of phenanthrenes to synthesis9,10-phenanthrenequinones.This method had the advantages of operation simple, goodyield and so on.. The main contents of the article include:Firstly, we have reviewed the research development of the methods for thepreparing of9,10-phenanthrenequinones.Secondly, the method of preparing unsymmetrical9,10-phenanthrenequinonesthrough intramolecular coupling of2-acetyl-biphenyls has been systematic researched.We prepared2-acetyl-biphenyls via a Suziki-Miyaura cross-coupling reaction at first.Then synthetize9,10-phenanthrenequinones through intramolecular coupling of2-acetyl-biphenyls with the condition of I2/DMSO. The parts with electron-donatingwere more reactive than those with electron-withdrawing ones, and hence gaverelatively higher yields.Thirdly, we investigated the effects of reaction conditions such as temperature,solvent, time and protection gas on the yield. We optimized the reaction conditions bycolumn chromatography separation. And the optimized reaction condition lied asfollowing: the ratio of substrate with I2was1:1, the temperature was100degreewithout the protection of gas in the solvent of DMSO. The highest isolated yield couldreach92%. The yield is moderate with the catalysis of lewis acid.Finally, we studied the reaction mechanism through detected the reactionintermediate with HNMR. We proposed the possible reaction mechanism.