It is disclosed that L-fructose can be produced in high yield from L-sorbose. The process involves the inversion of the hydroxyl groups on carbon atoms C3 and C4 of L-sorbose to produce L-fructose. This inversion can be accomplished in simple, commercial equipment with the aid of common reagents. L-sorbose or an appropriately blocked derivative thereof is reacted so as to introduce or create a good leaving group, preferably mesyl or tosyl, at chiral carbon C3 thereby displacing the hydroxyl previously at that position. The leaving group is then displaced, preferably under alkaline conditions, in such a way that the hydroxyl oxygen atom at chiral carbon C4 attaches to chiral carbon C3, thereby displacing the leaving group while forming a 3,4-oxirane (epoxide) ring. The 3,4-oxirane ring forms in a downward position relative to the Haworth presentation thereby inverting chiral carbon C3 during formation of the 3,4-oxirane ring. The 3,4-oxirane ring is then opened under acidic or alkaline conditions to yield a sugar ring with a hydroxyl group in a position above the sugar ring at chiral carbon C4, and a hydroxyl group in a downward position at C3. Removal of any remaining blocking groups yields L-fructose. This may be accomplished by acid hydrolysis. There are also disclosed novel classes of compounds which act as intermediaries in the synthesis of L-fructose.
据披露,
L-果糖可以从
L-山梨糖高产得到。该过程涉及使
L-山梨糖的碳原子C3和C4上的羟基发生反转,从而产生
L-果糖。这种反转可以在简单的商业设备中借助常见试剂完成。
L-山梨糖或适当阻断的衍
生物被反应,以引入或创建一个良好的离开基团,最好是甲磺酰基或对
甲苯磺酰基,置换手性碳原子C3上先前的羟基。然后,在碱性条件下,以使手性碳原子C4上的羟基氧原子附着到手性碳原子C3,从而将离开基团置换掉,同时形成一个3,4-环氧烷(
环氧化物)环。3,4-环氧烷环以相对于Haworth式呈现的下向位置形成,从而在形成3,4-环氧烷环时反转手性碳原子C3。然后,在酸性或碱性条件下打开3,4-环氧烷环,以得到一个糖环,其中手性碳原子C4上的羟基位于糖环上方,手性碳原子C3上的羟基位于下方。去除任何剩余的阻断基团可得到
L-果糖。这可以通过酸
水解来完成。还披露了作为
L-果糖合成中间体的新型化合物类别。