2867. (3β)-7-Dehydrocholesterol
Nomenclature
CAS number: 434-16-2
Cholesta-5,7-dien-3-ol; provitamin D3. C27H44O; mol wt 384.64.
C 84.31%, H 11.53%, O 4.16%.
Description and references
Occurs in higher animals and in man. Isoln from the horned snail, Buccinum undatum: Windaus et al., Z. Physiol. Chem. 241, 100 (1936); from pigskin: Windaus, Bock, ibid. 245, 168 (1937); Boer et al., Proc. K. Ned. Akad. Wet. 39, 622 (1936). Synthesis: Windaus et al., Ann. 520, 98 (1935); Rosenberg, Tinker, US 2215727; Buisman et al., Rec. Trav. Chim. 66, 83 (1947); P. N. Confalone et al., J. Org. Chem. 46, 1030 (1981). Irradiation with ultraviolet light produces vitamin D3; also lumisterol3 and tachysterol3: Windaus et al., Ann. 533, 118 (1938).
Properties
Hydrated plates from ether-methanol. The water of crystn is held tenaciously: Schenck et al., Ber. 69, 2705 (1936). When anhydr mp 150-151°. [α]D20 -113.6° (c = 1 in chloroform), Koch, Koch, J. Biol. Chem. 116, 757 (1936); [α]D20 -127.1° in benzene (Boer). All provitamins D have the same uv maxima at 260, 270, 281, 293.5 nm. Insol in water, sol in the usual organic solvents.Derivative
Acetate.C29H46O2; mol wt 426.67.
C 81.63%, H 10.87%, O 7.50%.
Properties
Crystals from methanol, mp 129-130°; [α]D20 -85.3° (c = 1.2 in benzene).Derivative
Benzoate.C34H48O2; mol wt 488.74.
C 83.55%, H 9.90%, O 6.55%.