Selected Vitamins - Natural Products Chemistry: Sources, Separations, and Structures - page 132

OH

H

H

H

H

8

1

HO

HO

OH

Vitamin D 3 1α,25-(OH) 2 -D 3

OH

OH

H

H

H

HO OH

HO OH

1α,25-(OH) 2 -16-ene-23-
yne-D 3 (analog V)

1α,25-Dihydroxy-22,24-diene-
24,26,27-trihomovitamin D (EB1089)

FIGURE 12.7 Chemical structures of related vitamin D compounds.

HO

HO

O

O

γ-Tocopherols

α-Tocopherols

HO

HO

O

O

β-Tocopherols δ-Tocopherols

FIGURE 12.8 Structures of vitamin E-related compounds.

The structure determination of α-tocopherol was completed in 1938, verifying
the empirical formula of Vit E as C 29 H 50 O 2 (Figure 12.8). This is confirmed by the
mass spectral data for Vit E and is shown in Figure 12.9.
Since vegetables and fruits contain a relatively low content of Vit E, many meth-
ods have been developed to extract Vit E, including liquid extraction, supercritical