Chemical Properties
white fine crystalline powder or needles
Uses
Cholesteryl acetate is used in cosmetics, wrist watches, thermometers, propane tank volume indicators, video displays, pharmaceuticals.
Uses
Cholesteryl acetate is derived from cholesterol, which is a major component of all biological membranes. Approximately 25% of total brain lipid is made up of cholesterol, which is the principal sterol of higher animals. Cholesterol is found in all body tissues, with particularly high concentrations in the brain, spinal cord, and animal fats or oils. Additionally, cholesterol is the main constituent of gallstones.
Preparation
Cholesteryl acetate can be synthesized by the reaction of cholesterol with acetic anhydride in the presence of a catalyst such as pyridine or sulfuric acid. The reaction proceeds as follows:
Cholesterol + Acetic anhydride → Cholesteryl acetate + Acetic acid
The reaction is typically carried out at room temperature or slightly elevated temperatures for several hours. The resulting cholesteryl acetate can be purified by recrystallization from a suitable solvent such as ethanol or acetone.
Definition
ChEBI: Cholesteryl acetate is a cholesterol ester obtained by formal acylation of the hydroxy group of cholesterol by acetic acid. It has a role as a human metabolite. It is a cholesteryl ester and an acetate ester.
Reactions
Monophthalic acid epoxidation of cholesteryl acetate:
A solution of 10 g (0.023 mole) of cholesteryl acetate (mp 112-114°) in ether (50 ml) is mixed with a solution containing 8.4 g (0.046 mole) of monophthalic acid (Chap. 17, Sec. II) in 250 ml of ether. The solution is kept at reflux for 6 hours and then the solvent is removed by distillation (steam bath). The residue is dried under vacuum and digested with 250 ml of dry chloroform. The mixture was filtered to give 6.7 g of phthalic acid (87% recovery). The solvent in the filtrate was evaporated under reduced pressure and the residue was crystallised from 30 ml of methanol to give 6.0 g (58% yield) of β-oxocholesterol acetate. Recrystallisation gives the pure product, melting point 111-112°. Concentration of the filtrate gives 1.55 g (15 per cent yield) of α-oxocholesterol acetate with a melting point of 101-103° after crystallisation from ethanol.
Purification Methods
Crystallise the acetate from n-pentanol or Me2CO. Also purify it by chromatography through silica gel and eluting with MeOH. [Beilstein 6 III 2607, 6 IV 4004.]
