Sterol hydroperoxides

After a few minutes drying in air sterol hydroperoxides, nitrate esters, triazines and aromatic amines yield blue-violet chromatogram zones on a pale blue to violet background [1, 3]. Polynitroaromatics yield yellow to dark beige zones [3]. 

De Fabiani, E., Caruso, D., Cavaleri, M. et al. (1996) Cholesta-5,7,9(ll)-trien-3p-ol found in plasma of patients with Smith-Lemli-Opitz syndrome indicates formation of sterol hydroperoxide. J. Lipid Res. 31 y 2280-7. 

Asymmetric epoxidation, dihydroxylation, aminohydroxylation, and aziridination reactions have been reviewed.62 The use of the Sharpless asymmetric epoxidation method for the desymmetrization of mesa compounds has been reviewed.63 The conformational flexibility of nine-membered ring allylic alcohols results in transepoxide stereochemistry from syn epoxidation using VO(acac)2-hydroperoxide systems in which the hydroxyl group still controls the facial stereoselectivity.64 The stereoselectivity of side-chain epoxidation of a series of 22-hydroxy-A23-sterols with C(19) side-chains incorporating allylic alcohols has been investigated, using m-CPBA or /-BuOOH in the presence of VO(acac)2 or Mo(CO)6-65 The erythro-threo distributions of the products were determined and the effect of substituents on the three positions of the double bond (gem to the OH or cis or trans at the remote carbon) partially rationalized by molecular modelling. 

When sterols are oxidised at moderate temperatures (<100 °C), their reaction products are mainly derived from hydroperoxides, but at temperatures close to 200 °C and above, thermal reactions... 

Of the four previous sterols isolated from Bryopsis pennata, cholesta-5,20,24-trien-3P-ol is in a large majority, with just over 78% of the total sterol fraction. The following sterols, related to derosterol and all isolated from species of the genus Codium, are oxidized in position 7. The origin of this type of sterol sometimes arises from extractive process by photosensitized aUylic oxidation, especially for hydroperoxides. 

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