中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
2-脱氧-1,5-脱水葡萄糖醇 | 1,5-anhydro-2-deoxy-D-lyxo-hexitol | 3971-47-9 | C6H12O4 | 148.159 |
—— | (3S,4R)-dihydroxy-(2R)-(hydroxymethyl)tetrahydropyran | 13035-11-5 | C6H12O4 | 148.159 |
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 |
1,6-脱水-β-D-葡萄糖 | levoglucosan | 498-07-7 | C6H10O5 | 162.142 |
The reaction between acetic anhydride and several hydroxytetrahydropyrans in the presence of boron trifluoride has been studied. 2-Methyl-3-hydroxytetrahydropyran, 2-hydroxymethyl-4,5-dihydroxytetrahydropyran, and 3,4-dihydroxytetrahydropyran all underwent normal acetolysis to the expected straight-chain polyol acetates. Optically active forms of cis-and trans-3,4-dihydroxytetrahydropyran gave the same, inactive pentanetetrol, showing that racemization of the active centers had accompanied ring cleavage. 2-Hydroxymethyl-tetrahydropyran gave 1,3,6-hexanetriol besides the expected 1,2,6-isomer. The reagent did not cleave 4-hydroxytetrahydropyran nor dihydro-D-galactal, but the latter underwent hydroxyl inversion to give dihydro-D-altral. 1,5-Anhydro-D-sorbitol (polygalitol) appeared to undergo both ring fission and inversion.
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.