一种木葡聚糖类寡糖的化学合成及生物活性

天然木葡聚糖类寡糖是一类对植物生长具有调节作用的寡糖, 本文以3个单糖组分为原料, 经5步合成了一种木葡聚糖三糖(1)(总产率15%), 以及该三糖的糖苷缀合物1a及其异构体1b. 利用糖基化立体选择性原则, 一步偶联反应同时得到所需的α,β连接产物, 整个合成路线高效简捷. 活性测试结果表明, 3种目标寡糖在1 mg/L浓度下, 对烟草的生长均显示出一定的促进作用, 表明所合成的3种寡糖有望发展成为植物生长促进剂.

Synthesis and Biological Activities of Xyloglucan Trisaccharides

Native xyloglucan oligosaccharides are a kind of growth regulator in plant development. A xyloglucan trisaccharide : α-D-xylopyranosyl- ( 1,6 ) -β-D-glucopyranosyl- ( 1,4 ) -D-glucopyranose ( 1 ) and its derivatives were synthesized by three monosaccharide units. Glycosylation of isopropyl 2,3-di-O-acetyl-4, 6-0-benzylidene-1-thio-β-D-glucopyranoside(3) as the donor with 4-methoxyphenyl 2,3,6-tri-O-benzoyl-β-D-glu-copyranoside (4) gave disaccharide (5). Deprotection of 4,6-O-benzylidene of compound 5 gave 6 as disaccharide acceptor. Then coupling of isopropyl 2,3,4-tri-O-benzyl-1-thio-β-D-xylopyranoside(2) with 6 afforded a and β trisaccharides(7) and separation of compound 7 gave 8(α) and 9(/3β). Global deprotection of compound 8 obtained trisaccharide 1. The whole route involves five steps and the total yield is 15%. Synthetic trisaccharides were added to the culture medium to detect their effects on tobacco growth. The results show that three synthesized oligosaccharides promote the growth of tobacco at the level of 1 mg/L. These results suggest that synthesized trisaccharides may be good prospects for the application in the control of plant growth.