Sato Shingo, Nojiri Toshikatsu, Onodera Jun-ichi
Department of Chemistry and Chemical Engineering, Faculty of Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa-shi, Yamagata 992-8510, Japan.
Carbohydr Res. 2005 Feb 28;340(3):389-93. doi: 10.1016/j.carres.2004.12.019.
The direct C-glycosylation of methylphloroacetophenone 8 with d-glucose gave C-beta-d-glucopyranosylmethylphloroacetophenone (7) in 65% yield, which, on oxidation in the presence of small amount of pyridine under an oxygen atmosphere afforded the quinone 9, oxidized at the methylated position of the benzene ring as a pair of diastereomers in 27% yield. A detailed NMR analysis and a comparison of the UV-vis and CD spectra of their acetates indicated that the structure and stereochemistry of 9 was (1R,1'S,2R,3S,3aS,5R and 1R,1'S,2R,3S,3aS,5S)-7-acetyl-2-(1',2'-dihydroxyethyl)-5-methyl-3,5,6-trihydroxy-8-oxofuro[3,2-d]benzo[b]furan.
间氯苯乙酮8与d-葡萄糖直接进行C-糖基化反应，以65%的产率得到C-β-D-吡喃葡萄糖基间氯苯乙酮（7），在氧气气氛下，于少量吡啶存在下对其进行氧化反应，得到醌9，其在苯环甲基化位置被氧化，以非对映体对的形式得到，产率为27%。对其乙酸酯的详细核磁共振分析以及紫外可见光谱和圆二色光谱的比较表明，9的结构和立体化学为(1R,1'S,2R,3S,3aS,5R和1R,1'S,2R,3S,3aS,5S)-7-乙酰基-2-(1',2'-二羟基乙基)-5-甲基-3,5,6-三羟基-8-氧代呋喃并[3,2-d]苯并[b]呋喃。
