Characterization of Thitsiol Dimer Structure by NMR Spectroscopy
The structures of thitsiol dimers produced in the initial enzymatic polymerization were characterized by means of high resolution NMR spectroscopy involving two-dimensional NMR measurements such as field gradient DQF-COSY, HMQC, and HMBC experiments. Based on analysis of the analog polymer, most of the complicated overlapping proton and carbon absorptions were assigned. The results show that oxidative coupling of thitsiol catalyzed by laccase leads to the formation of three major dimers, 1,1’,2,2’-tetrahydroxy-3,3’-dialkenyl-5,5’-biphenyl, 1,1’,2,2’-tetrahydroxy-3,3’-dialkenyl-6,5’-biphenyl, and 1,1’,2,2’-tetrahydroxy-3,4’-dialkenyl-5,5’-biphenyl, respectively. The thitsiol dimers are almost all nuclear-nuclear (C-C) couplings, which differ from the nuclear-side chain (C-O-C) couplings of urushiol. Based on these results, the color of the lacquer film and the polymerization mechanism of thitsiol are discussed.
Rong Lu Daisuke Kanamori Tetsuo Miyakoshi
Department of Applied Chemistry, School of Science and Technology, Meiji University, 1-1-1 Higashi-mita, Tama-ku, Kawasaki-shi, 214-8571, Japan
国际会议
南京
英文
678-680
2010-10-22（万方平台首次上网日期，不代表论文的发表时间）