Vitamin D5 (VD5) - Витамин D5

(1S,3Z)-3-[(2E)-2-[(1R,3aR,7aR)-1-[(2R,5R)-5-ethyl-6-methyl-heptan-2-yl]-7a-methyl-2,3,3a,5,6,7-hexahydro-1H-inden-4-ylidene]ethylidene]-4-methylidene-cyclohexan-1-olVitamin D5 is a form of vitamin D.Analogues have been proposed for use as antitumor agents.7-Dehydrositosterol is a sterol which serves as a precursor for sitocalciferol (vitamin D5).Vitamin D is a group of fat-soluble prohormones, the two major forms of which are vitamin D2 (or ergocalciferol) and vitamin D3 (or cholecalciferol). Vitamin D obtained from sun exposure, food, and supplements is biologically inert and must undergo two hydroxylation reactions to be activated in the body.  The term vitamin D also refers to these metabolites and other analogues of these substances.