Application of the DFRC (Derivatization Followed by Reductive Cleavage) Method to Dilignols

Abstract

The DFRC method was applied to dimeric model compounds of lignin; dehydrodiconiferyl alcohol, syringaresinol, pinoresinol, syringylglycerol‐β‐sinapyl ether, and guiacylglycerol‐β‐coniferyl ether. Dehydrodiconiferyl alcohol yielded no coniferyl alcohol, but syringaresinol and pinoresinol gave small amounts of corresponding p‐hydroxycinnamyl alcohol. In the case of syringaresinol, an acetylated bromo dihydro‐(Compound 1, 23%) and tetrahydronaphthalene (Compound 2, 52%) were obtained after acetyl bromide treatment, the first step in the DFRC method. Further, a small amount of sinapyl alcohol diacetate was obtained from compounds 1 and 2 by zinc and successive acetylation treatments. Compound 2 yielded a larger amount of sinapyl alcohol than compound 1. We thank Dr. Shingo Kawai, Shizuoka University, for giving us guiacylglycerol‐β‐guiacyl ether. We also thank Dr. Siaw Onwona‐Agyeman, Gifu University, for helping in the preparation of this manuscript. Finally, we thank the staff of the Division of Instrumental Analysis, Life Science Research Center, Gifu University, for their help in 1H‐NMR, 13C‐NMR, and GC‐MS analysis.