中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
1,5-无水葡萄糖醇 | 1,5-anhydro-D-glucitol | 154-58-5 | C6H12O5 | 164.158 |
alpha-甲基葡萄糖甙 | methyl-alpha-D-glucopyranoside | 97-30-3 | C7H14O6 | 194.185 |
Several methyl glycopyranosides have been hydrogenated under pressure at 180 °C with copper chromite catalyst in dioxane. Many glycosides underwent hydroxyl group inversion and another reaction observed consisted of hydrogenolytic removal of the methoxyl group coupled with reduction of a hydroxyl group to a methylene group. Other glycosides were stable under these conditions, and these included methyl β- and methyl α-D-glucopyranosides and unexpectedly methyl β-D-mannopyranoside and methyl α-D-talopyranoside. The data indicated that generally β-glycosides are more stable than their α-anomers in the hexopyranoside series and that the methyl hexopyranosides are more stable than the methyl pentopyranosides. Explanations have been made in the theoretical section in order to cover these observations. At 240 °C, however, methyl α-D-glucopyranoside is hydrogenolyzed giving 11% of 1,5-anhydro-4-deoxy-hexitols. These polyols have been fractionated and the mixture shown to contain lyxo- and arabo-1,5-anhydro-4-deoxy-D-hexitols.
在二氧六环中使用铜铬催化剂,在180°C和压力下,对几种甲基糖苷进行了氢化。许多糖苷发生了羟基组反转,观察到的另一种反应是甲氧基团的氢解与羟基还原为亚甲基。其他糖苷在这些条件下是稳定的,包括甲基β-和甲基α-D-葡萄糖苷以及出人意料的是甲基β-D-甘露糖苷和甲基α-D-塔洛糖苷。数据表明,在己糖苷系列中,β-糖苷通常比它们的α-异构体更稳定,甲基己糖苷比甲基戊糖苷更稳定。理论部分已经做出解释,以涵盖这些观察结果。然而,在240°C时,甲基α-D-葡萄糖苷被氢解,产生11%的1,5-脱水-4-脱氧己糖醇。这些多元醇已经被分离,并证明混合物中含有来苏-和阿拉伯-1,5-脱水-4-脱氧-D-己糖醇。
The hydrogenolysis of methyl α-D-glucopyranoside at 180° to 220 °C. was found to yield in addition to the polyols obtained at 240° substantial quantities of hydro-D-glucal (2-deoxy-1,5-anhydro-D-sorbitol), smaller amounts of 2-deoxymethyl glucoside, and the hitherto unknown hydro-D-altral, as well as trace amounts of several other unidentified deoxy-glycosides and 1,5-anhydrohexitols. These findings accordingly revise the reduction mechanism proposed earlier and show that inversion of one or more hydroxyl groups can occur during the hydrogenolysis.