125136-40-5

Upstream product

• 604-35-3 Cholesteryl acetate 
• 57-88-5 cholesterol 
• 51238-16-5 3β-acetoxy-4β-hydroxy-5-cholestene 
• 83685-71-6 3β-benzoyloxycholest-5-en-4α-ol 
• 50611-92-2 3β-benzoyloxycholest-5-ene-4-one 
• 604-32-0 cholesteryl benzoate 
• 83685-71-6 3β-benzoyloxy-4β-hydroxy-5-cholestene 
• 601-54-7 Cholest-5-en-3-one 
• 20230-31-3 (4,5)α-epoxy-5α-cholestan-3β-ol 
• 51238-14-3 4α-acetoxy-cholest-5-en-3-one 

Relevant academic research and scientific papers

H-Atom Abstraction vs Addition: Accounting for the Diverse Product Distribution in the Autoxidation of Cholesterol and Its Esters

We recently communicated that the free-radical-mediated oxidation (autoxidation) of cholesterol yields a more complex mixture of hydroperoxide products than previously appreciated. In addition to the epimers of the major product, cholesterol 7-hydroperoxide, the epimers of each of the regioisomeric 4- and 6-hydroperoxides are formed as is the 5α-hydroperoxide in the presence of a good H-atom donor. Herein, we complete the story by reporting the products resulting from competing peroxyl radical addition to cholesterol, the stereoisomeric cholesterol-5,6-epoxides, which account for 12% of the oxidation products, as well as electrophilic dehydration products of the cholesterol hydroperoxides, 4-, 6-, and 7-ketocholesterol. Moreover, we interrogate how their distribution - and abundance relative to the H-atom abstraction products - changes in the presence of good H-atom donors, which has serious implications for how these oxysterols are used as biomarkers. The resolution and quantification of all autoxidation products by LC-MS/MS was greatly enabled by the synthesis of a new isotopically labeled cholesterol standard and corresponding selected autoxidation products. The autoxidation of cholesteryl acetate was also investigated as a model for the cholesterol esters which abound in vivo. Although esterification of cholesterol imparts measurable stereoelectronic effects, most importantly reflected in the fact that it autoxidizes at 4 times the rate of unesterified cholesterol, the product distribution is largely similar to that of cholesterol. Deuteration of the allylic positions in cholesterol suppresses autoxidation by H-atom transfer (HAT) in favor of addition, such that the epoxides are the major products. The corresponding kinetic isotope effect (kH/kD ～ 20) indicates that tunneling underlies the preference for the HAT pathway.

Cholesterol transformations during heat treatment

The aim of the study was to characterise products of cholesterol standard changes during thermal processing. Cholesterol was heated at 120 °C, 150 °C, 180 °C and 220 °C from 30 to 180 min. The highest losses of cholesterol content were found during thermal processing at 220 °C, whereas the highest content of cholesterol oxidation products was observed at temperature of 150 °C. The production of volatile compounds was stimulated by the increase of temperature. Treatment of cholesterol at higher temperatures i.e. 180 °C and 220 °C led to the formation of polymers and other products e.g. cholestadienes and fragmented cholesterol molecules. Further studies are required to identify the structure of cholesterol oligomers and to establish volatile compounds, which are markers of cholesterol transformations, mainly oxidation.

Improved synthesis and in vitro evaluation of the cytotoxic profile of oxysterols oxidized at C4 (4α- and 4β-hydroxycholesterol) and C7 (7-ketocholesterol, 7α- and 7β-hydroxycholesterol) on cells of the central nervous system

Whereas the biological activities of oxysterols oxidized at C7 (7-ketocholesterol (7KC), 7β-hydroxycholesterol (7β-OHC), 7α-hydroxycholesterol (7α-OHC)) are well documented, those of oxysterols oxidized at C4 (4β-hydroxycholesterol (4β-OHC), 4α-hydroxycholesterol (4α-OHC)) are not well known, especially on the cells of the central nervous system. Therefore, an improved methodology has been validated for 4β-OHC and 4α-OHC synthesis, and the effects on cell viability and cell growth of these molecules were studied on immortalized, tumoral and normal brain cells (158N, C6 and SK-N-BE cells, and mixed primary cultures of astrocytes and oligodendrocytes). Whereas inhibition of cell growth with 7KC, 7β-OHC, and 7α-OHC is associated with a decrease of cell viability (cytotoxic activities), our data establish that 4β-OHC and 4α-OHC have no effect on cell viability, and no or minor effect on cell growth evocating cytostatic properties. Thus, comparatively to oxysterols oxidized at C7, the toxicity of oxysterols oxidized at C4 is in the following range of order: 7KC ≥ 7β-OHC > 7α-OHC > (4β-OHC ≥ 4α-OHC). Interestingly, to date, 4β-OHC and 4α-OHC are the only oxysterols identified with cytostatic properties suggesting that these molecules, whereas not cytotoxic, may have some interests to counteract cell proliferation.

Synthesis of [D4]- and [D7]-4β- hydroxycholesterols for use in a novel drug-drug interaction assay

Cytochrome P450 3A (CYP3A) enzymes are involved in the metabolism of over half of today's prescription drugs. As a result, drugs metabolized by CYP3A have a risk of drug-drug interactions (DDIs). Recent studies have shown the potential to use 4β-hydroxych

A novel allylic oxidation using a combination of formic acid and selenium dioxide

A combination of formic acid and selenium dioxide in dioxane has been found to be an efficient system for the allylic oxygenation of olefins, in particular for sterically hindered ones, leading to the corresponding allylic alcohols or formates.

Reactions of steroidal 4,5- and 5,6-epoxides with strong bases

A series of C-3 oxygenated and unsubstituted (4,5)α, (4,5)β, (5,6)α, and (5,6)β epoxy steroids has been prepared, and the reactions of these compounds with strong bases (potassium tert-butoxide, LDA, and LDEA) were investigated.Only LDEA gave rise to product formation; β elimination of the epoxide to give a β-hydroxy olefin was observed in this case.The regioselectivity of product formation is consistent with a mechanism of rearrangement involving removal of a hydrogen located syn to the epoxide oxygen.In some cases, a directing influence from a polar substituent (OH) of the starting material was also apparent.The (13)C nmr spectra of the steroidal epoxides used in this study were assigned; these data are diagnostic of the conformation of ring A of (4,5)α and (4,5)β epoxy steroids.

Stereochemistry of the Reduction of 3β-Benzoyloxycholest-5-en-4-one with Sodium Borohydride

Reduction of 3β-benzoyloxycholest-5-en-4-one (3) with sodium borohydride under various conditions affords only minor amounts of 3β-benzoyloxycholest-5-en-4β-ol (2a).The major product is the 4α-isomer (6).Using sodium borodeuteride it has been shown that t