ビタミンD5

Vitamin D₅

Names
IUPAC name (1S,3Z)-3-[(2E)-2-[(1R,3aS,7aR)-1-[(1R,4S)-4-ethyl-1,5-dimethylhexyl]-7a-methyl-2,3,3a,5,6,7-hexahydro-1H-inden-4-ylidene]ethylidene]-4-methylene-1-cyclohexanol
Other names Sitocalciferol (5Z,7E)-(3S)-9,10-secoporiferasta-5,7,10(19)-trien-3-ol
Identifiers
CAS Number	71761-06-3 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:33279
ChemSpider	7826639 Y
PubChem CID	9547700
UNII	0W2I161LCL Y
InChI InChI=1S/C29H48O/c1-7-23(20(2)3)12-10-22(5)27-16-17-28-24(9-8-18-29(27,28)6)13-14-25-19-26(30)15-11-21(25)4/h13-14,20,22-23,26-28,30H,4,7-12,15-19H2,1-3,5-6H3/b24-13+,25-14-/t22-,23+,26+,27-,28+,29-/m1/s1 Y Key: RMDJVOZETBHEAR-GHTRHTQZSA-N Y InChI=1/C29H48O/c1-7-23(20(2)3)12-10-22(5)27-16-17-28-24(9-8-18-29(27,28)6)13-14-25-19-26(30)15-11-21(25)4/h13-14,20,22-23,26-28,30H,4,7-12,15-19H2,1-3,5-6H3/b24-13+,25-14-/t22-,23+,26+,27-,28+,29-/m1/s1 Key: RMDJVOZETBHEAR-GHTRHTQZBN
SMILES O[C@@H]1CC(\C(=C)CC1)=C\C=C2/CCC[C@]3([C@H]2CC[C@@H]3[C@H](C)CC[C@H](CC)C(C)C)C
Properties
Chemical formula	C29H48O
Molar mass	412.702 g·mol−1

ビタミンD₅（sitocalciferol）はビタミンDの一種である。

研究

ビタミンD₃の一種であるカルシトリオールのアナログが抗腫瘍剤として使用されることが提案されている。ビタミンD₃に関する研究では、前立腺がんにおける細胞増殖の阻害が示されているが、ビタミンD₃の高用量投与は高カルシウム血症を引き起こす。前立腺がんに対するビタミンD₅の効果も研究されており、ビタミンD₃とは異なり、ビタミンD₅は腫瘍細胞の増殖を阻害する一方で高カルシウム血症を引き起こさない。抗腫瘍剤として最も研究されているビタミンD₅の類似体は1α-ヒドロキシビタミンD_5.である。

1α-ヒドロキシビタミンD₅

1α-Hydroxyvitamin D₅ is a chemical derivative of vitamin D₅. The motive to study 1α-hydroxyvitamin D₅ as a potential pharmaceutical drug stemmed from the tendency of calcitriol, a natural metabolite produced in the kidney, to cause toxic hypercalcemia in patients when dosed at concentrations needed to interrupt prostate cancer cells' cycle and stimulate apoptosis. And while supplementation with dexamethasone decreases hypercalcemia, bypassing it with an equally effective tumor suppressant would reduce patient cost and stress. Thus, the therapeutic effects of 1α-Hydroxyvitamin D₅ as a potential antitumor agent without the side effects of calcitriol became a topic of study.

1α-Hydroxyvitamin D₅ was first synthesized in 1997 by researchers in the Department of Chemistry at the University of Chicago, under Robert M. Moriarty and Dragos Albinescu. By 2005, the group had revised its synthesis method for a more streamlined, higher yield-producing route. It involved the photochemical conversion of precursor 7-dehydrositosteryl acetate to contain a conjugated triene system, a hallmark of this analog, followed by hydroxylation, photoisomerization, and deprotection steps. Their overall yield was 48%.

See also

• 7-Dehydrositosterol
• Calcipotriene