Methylene carbon polyprenol

The arrangement of trans isoprene-units is observed more in detail from the 13C-NMR signal splitting of C-l methylene carbon [94, 97], as shown in Figure 11.19. The mushroom rubber shows two peaks due to the trans isoprene-unit in dimethylallyl-trans and trans-trans linkages similar to those of the two-trans polyprenol. On the other hand, the rubbers from Goldenrod and Sunflower exhibit three peaks similar to the overlap of peaks of two-trans and three-trans polyprenols. This suggests the presence... 

Similarly, polyprenols-15 to -20, isolated from the leaves of Ginkgo viloba, showed the same splitting of C-l methylene carbon signals, as shown in Fig. 2. From the intensity ratios of these signals it was found that these polyprenols contained two internal trans and 11 to 16 internal cis units aligned as given in (IV) (11). 

Figure 1. C-l methylene carbon signals in polyprenol-11 from Ficus elastica. Reproduced with permission from Ref. 10. Copyright 1979, The Biochemical Society.

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