| 摘要 |
<p>NEW MATERIAL:An intermediate for synthesis of Rebaudioside A of formulaI, wherein the 4-and 6-positions of the D-glucose (a) bonded to the nonsugar part via the ether linkage are protected by the protective group common to the both groups, the 2-,3-,4-, and 6-positions of the D-glucoses bonded to the 2-and 3-positions of the D-glucose (a) and the D-glucose bonded to the nonsugar part via the ester linkage are protected by acyl groups respectively. EXAMPLE:Compound o formula II: (AC is acetyl group). USE:Intermediate for synthesis of good-quality sweetening agents, Rebaudioside A, contained in the terrestrial part of the composite plant in an amount of about 2%. PROCESS:Novel compounds of formula III are subjected to the glycosylation with a glucose orthoester to give the objective compound of formula II. Compounds of formula III are prepared from stevioside by microorganism action, alkali treatment, and protective group formation of the hydroxyl groups at the 4-and 6-positions of the glucose.</p> |
