What is Vitamin D3 ?

Cholecalciferol (also known as toxiferol) is a form of vitamin D, also called vitamin D3. Vitamin D3 is vitamins drug mainly promote absorption and deposition of calcium and phosphorus in intestines.It is used to treat rickets and osteomalacia,etc.
It is structurally similar to steroids such as testosterone, cholesterol, and cortisol (though vitamin D3 itself is a secosteroid).Cholecalciferol is produced industrially for use in vitamin supplements and to fortify foods by the ultraviolet irradiation of 7-dehydrocholesterol extracted from lanolin found in sheep's wool. Paraphrasing a more detailed explanation, cholesterol is extracted from wool grease and wool wax alcohols obtained from the cleaning of wool after shearing. The cholesterol undergoes a four step process to make 7-dehydrocholesterol, the same compound that is stored in the skin of animals.

7-Dehydrocholesterol is the precursor of vitamin D3. Within the epidermal layer of skin, 7-Dehydrocholesterol undergoes an electrocyclic reaction as a result of UVB radiation, resulting in the opening of the vitamin precursor B-ring through a conrotatory pathway. Following this, the previtamin D3 undergoes a antarafacial sigmatropic rearrangement  and therein finally isomerizes to form vitamin D3.
Cholecalciferol is then hydroxylated in the liver to become calcifediol (25-hydroxyvitamin D3).
Next, calcifediol is again hydroxylated, this time in the kidney, and becomes calcitriol (1,25-dihydroxyvitamin D3). Calcitriol is the most active hormone form of vitamin D3.

CAS:67-97-0
Molecular Formula: C27H44O
Molecular Weight: 384.64 g/mol