Title: Cholesterol
CAS Registry Number: 57-88-5
CAS Name: (3b)-Cholest-5-en-3-ol
Additional Names: cholesterin
Molecular Formula: C27H46O
Molecular Weight: 386.65
Percent Composition: C 83.87%, H 11.99%, O 4.14%
Literature References: Principal sterol of the higher animals. Found in all body tissues, esp in the brain, spinal cord, and in animal fats or oils. Main constituent of gallstones. Prepd commercially from the spinal cord of cattle by petr ether extraction of the nonsaponifiable matter. Also produced from wool grease. Cholesterol from animal organs always contains cholestanol (dihydrocholesterol) and other satd sterols. Purification by repeated bromination: Schoenheimer, J. Biol. Chem. 105, 355 (1934); Fieser, Org. Synth. coll. vol. IV, 195 (1963). Laboratory procedure for isoln from gallstones: L. F. Fieser, Organic Experiments (Heath, Boston, 3rd ed., 1964) p 70. Total synthesis: Keana, Johnson, Steroids 4, 457 (1964). Reviews and bibliographies: Fieser, Fieser, Steroids (Reinhold, New York, Chapman & Hall, London, 1959); Lettré et al., Ueber Sterine, Gallensäuren und verwandte Naturstoffe (Stuttgart, 2nd ed., 1955); R. P. Cook, Cholesterol (Chemistry, Biochemistry and Pathology) (Academic Press, New York, 1958) 542 pp; J. T. Gwynne, J. F. Strauss, Endocr. Rev. 3, 299-329 (1982).
Properties: Monohydrate, pearly leaflets or plates from dil alcohol. Becomes anhydr at 70-80°. When anhydr mp 148.5°. Has been sublimed as orthorhombic needles. bp0.5 233°; bp760 360° (some decompn). d 1.03 (monohydrate); d1919 1.052 (anhydr). [a]D20 -31.5° (c = 2 in ether); [a]D20 -39.5° (c = 2 in chloroform). Absorption spectrum: Heilbron et al., J. Chem. Soc. 1928, 47. Practically insol in water (about 0.2 mg/100 ml H2O). Slightly sol in alc (1.29% w/w at 20°), more sol in hot alc (100 g of satd 96% alcoholic soln contains 28 g at 80°). One gram dissolves in 2.8 ml ether, in 4.5 ml chloroform, in 1.5 ml pyridine. Also sol in benzene, petr ether, oils, fats. Soly in aq solns of bile salts: Rosin, Z. Physiol. Chem. 124, 282 (1923). Solubilization: Gemant, Life Sci. 1, 233 (June 1962). Is pptd by digitonin. Gives intense red color with rosaniline in chloroform soln.
Melting point: mp 148.5°
Boiling point: bp0.5 233°; bp760 360° (some decompn)
Optical Rotation: [a]D20 -31.5° (c = 2 in ether); [a]D20 -39.5° (c = 2 in chloroform)
Density: d 1.03 (monohydrate); d1919 1.052 (anhydr)
Derivative Type: Methyl ether
Molecular Formula: C28H48O
Molecular Weight: 400.68
Percent Composition: C 83.93%, H 12.07%, O 3.99%
Properties: Crystals from acetone, mp 84°. [a]D20 -45.8° (c = 1.2 in chloroform).
Melting point: mp 84°
Optical Rotation: [a]D20 -45.8° (c = 1.2 in chloroform)
Derivative Type: Acetate
Molecular Formula: C29H48O2
Molecular Weight: 428.69
Percent Composition: C 81.25%, H 11.29%, O 7.46%
Properties: Needles from acetone, mp 115-116°. [a]D20 -47.4° (c = 2 in chloroform).
Melting point: mp 115-116°
Optical Rotation: [a]D20 -47.4° (c = 2 in chloroform)
Derivative Type: Benzoate
Molecular Formula: C34H50O2
Molecular Weight: 490.76
Percent Composition: C 83.21%, H 10.27%, O 6.52%
Properties: mp 145.5° (the melt becomes clear at 180°). [a]D25 -13.7° (c = 0.9 in chloroform).
Melting point: mp 145.5° (the melt becomes clear at 180°)
Optical Rotation: [a]D25 -13.7° (c = 0.9 in chloroform)
Use: Pharmaceutic aid (emulsifying agent).
Cholestyramine Resin Cholic Acid Choline Alfoscerate Choline Chloride Choline Dehydrocholate

CAS number 57-88-5 YesY
PubChem 5997
ChemSpider 5775 YesY
KEGG D00040 YesY
ChEBI CHEBI:16113 YesY
Jmol-3D images Image 1
Molecular formula C27H46O
Molar mass 386.65 g/mol
Appearance white crystalline powder[2]
Density 1.052 g/cm3
Melting point 148–150 °C[2]
Boiling point 360 °C (decomposes)
Solubility in water 0.095 mg/L (30 °C)
Solubility soluble in acetone, benzene, chloroform, ethanol, ether, hexane, isopropyl myristate, methanol
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references
Microscopic appearance of cholesterol crystals in water. Photo taken under polarized light.

Cholesterol, from the Ancient Greek chole- (bile) and stereos (solid) followed by the chemical suffix -ol for an alcohol, is an organic molecule. It is a sterol (or modified steroid),[3] and an essential structural component of animal cell membranes that is required to establish proper membrane permeability and fluidity. Cholesterol is thus considered within the class of lipid molecules.

In addition to its importance within cells, cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acids, and vitamin D.[4] Cholesterol is the principal sterol synthesized by animals, all cells; in vertebrates the liver typically produces greater amounts than other cells. It is almost completely absent among prokaryotes (i.e., bacteria), although there are some exceptions such as Mycoplasma, which require cholesterol for growth.[5]

François Poulletier de la Salle first identified cholesterol in solid form in gallstones in 1769. However, it was not until 1815 that chemist Michel Eugène Chevreul named the compound "cholesterine".[6][7]