A polyprenyl composition consisting essentially of a mixture of polyprenyl compounds represented by the following formula ##STR1## wherein A.sub.1 represents a hydroxyl or acetyloxy group, ##STR2## represents a trans-isoprene unit ##STR3## represents a cis-isoprene unit, and n is an integer of from 11 to 19, said mixture containing substantial amounts of at least three compounds of formula (I) wherein n represents 14, 15 and 16 respectively as essential ingredients in a total amount of at least 70% by weight based on the weight of the mixture; and new compounds derived from the polyprenyl compounds of formula (I). These composition and compounds are useful for the synthesis of mammalian dolichols. The polyprenyl composition can be prepared by extracting the leaves of Ginkgo biloba or Cedrus deodara with an oil-soluble organic solvent; if required, hydrolyzing the extract; and subjecting the extract to one or more of chromatography, fractional dissolution, fractional refrigerating precipitation and molecular distillation, thereby separating and recovering a fraction having a specified Rf value in silica thin-layer chromatography.
一种聚
戊二烯组合物,基本上由以下式表示的聚
戊二烯化合物混合物组成:其中A.sub.1代表羟基或乙酰氧基,代表反式
异戊二烯单元,代表顺式
异戊二烯单元,n为11至19的整数,所述混合物含有至少三种分别表示为n分别为14、15和16的式(I)化合物的重要成分,其总量至少占混合物重量的70%;以及从式(I)聚
戊二烯化合物衍生的新化合物。这些组合物和化合物可用于合成哺乳动物多立醇。聚
戊二烯组合物可以通过用油溶性有机溶剂提取
银杏叶或雪松叶制备;如有必要,
水解
提取物;并将
提取物经过色谱、分级溶解、分级冷却沉淀和分子蒸馏中的一种或多种处理,从而分离和回收在
硅胶薄层色谱中具有指定Rf值的分数。