Epoxy sterol

Migliuolo, A., Notaro, G., Piccialli, V., and Sica, D. (1991) Synthesis of the marine epoxy sterol 9a,lla-epoxy-5a-cholest-7-ene-3p,5,6p-triol. 

Consumption of food with sterols and their oxides is a health concern. Oxidation products of phytosterol, including epimers of 7-ketositosterol and 7-hydroxycampes-terol, 7-ketocampesterol, epimers of 5,6-epoxy-sitosterol, 5,6-epoxycamposterol, 24 a-ethylcholestane-3(3,5,6 (3-triol, and 24 a-methylcholestane-3(3,5,6 (3-triol, in deep-fried potato chips in palm oil, sunflower oil, and high oleic sunflower oil were quanhtahvely analyzed by PTLC followed by GC and GC-MS [73]. 

Wharton reaction2 (1, 439-440). This rearrangement of a,3-enones to allylic alcohols via an epoxy hydrazone has seen only occasional use outside of the sterol field because yields can be low. Some expedients have been shown by Dupuy and... 

An enzyme system from the yeast Saccharomyces cerevisiae is able to incorporate isoprenoid precursors into the C30 phytoene analogue (200) only in the presence of Mn and absence of NADPH. If NAD PH is present and Mn is replaced by Mg, the sterol precursor squalene (201) is produced.The substrate specificity of the chloroplast enzyme violaxanthin deepoxidase has been examined.In addition to the normal substrate violaxanthin [(35,5/ ,65,3 5,5 i ,6 5)- 5,6,5, 6 -diepoxy-5,6,5, 6 -tetrahydro-/3,j8-carotene-3,3-diol, (196)] several all-trans-monoepoxy-carotenoids, such as anthera-xanthin [5,6-epoxy-5,6-dihydro-/3,/3-carotene-3,3 -diol (197)], diadinoxanthin [5,6-epoxy-7, 8 -didehydro-5,6-dihydro-j8, 8-carotene-3,3 -diol (198)], and /3-cryptoxanthin epoxide [5,6-epoxy-5,6-dihydro-/3,/3-caroten-3-ol (199)], all with the 38,5R,6S) configuration, were utilized. Violeoxanthin (9-cis-violaxanthin) and other 9-cis-isomers were not affected. A carrot Daucus carota) tissue culture has been shown to incorporate [ C]acetate into carotenoids. ... 

Several polyhydroxy sterols were isolated from octocorals, alcyonaceans, gorgonians and other marine sources. Hippurin-I (58) [66], 3a-acetoxy-ll -hydroxy-24-methyl-22,25-epoxy-5a-furostan-18,20/S-lactone (59), 3a-acetoxy-24-methyl-ll/8,18 18,20/J 22,25-triepoxy-5a-furostane (60) and several of their analogues were isolated from Isis hippuris collected in Okinawa by Higa [67]. A polyhydroxy sterol (61) containing the gorgosterol side chain was also present [68] (Fig. 6). 

Branched long-chain alcohols (IV) obtained by condensation of lower alcohols (Guerbet synthesis) have some importance as lipophilic surfactants, emollients, and surfactant intermediates. Alcohols and sterols derived by saponification of wool wax, such as Amerchol 400 Amerchol), Argowax Westbrook Lanolin), Super Hartolan and Lanethyl Croda), sterols from vegetable waxes and oils, diols (such as 2,4,7,9-tetramethyl-decyne-5-diol-4,7 (V) that is known as wetting agent) as well as long-chain epoxy hydrolysates (1,2-diols) are also of some importance. 

Cold-pressed plant oils and refined plant oils from Polish markets were assessed for contents of sterol oxidation products. The content of oxyphytosterols in refined oils was 2 to 2.5 times higher than in cold-pressed oils. The 7-hydroxy-phytosterols and 7-keto-phytosterols epimers were the predominant compounds in cold-pressed oil, whereas epoxy derivatives were predominant compounds in refined oils. Percentage composition of oxyphytosterol fraction differed from the phytosterol percentage fraction (Figure 6.5) (Rudzinska et al., 2001). 

Figure 2.12 Charge tagging with the GP reagent to an oxysterol. Oxidation of an oxysterol with a 3p-hydroxy-5-ene function (e.g., 24S,25-epoxycholesterol, C -3p-ol-24S,25-epoxide) to the analogous sterol with a 3-oxo-4-ene function (24S,25-epoxycholest-4-en-3-one, C -24S,25-epoxy-3-one) followed by derivatization with GP reagent.

Vegetable Oils. Triglycerides form the principal component of most edible oils obtained from seeds and fruits small amoimts of free fatty acids and sterols occur also. As shown in Fig. 130, i, olive oil, a typical example, can be easily separated by adsorption TLC into these three fractions. Oils containing triglycerides of epoxy- and hydroxy-acids as well as those of the ordinary fatty acids show very characteristic... 

Sterols and Related Products - The Westphalen rearrangement of some JP-substituted-bp-acetoxy-5Q -hydroxycholestanes has been studied and the products and kinetics shown to be dependent on the nature of the 5-substituent. The conformations of the products were studied and in the case of the Westphalen-Lettre derivatives it was shown that ring B is in the boat conformation. The boron trifluoride catalyzed cleavage of 30 -acetoxy-4a,5-epoxy-5Ci -cholestane afforded the expected backbone rearrangement products containing a 15(17) doable bond." A similar experiment with 5Q -acetoxy-5,ba-epoxy-5o -cholestane yielded some of the rearranged derivative XW after a reaction time of 25 seconds, along with the e q)ected isomer " ... 

This Mediterranean species yielded a series of sterols trioxygenated at 3P,SP and containing a ketone at 6 or 7 or an epoxy at 5a,6a. Most of these sterols have strong similarities with other sterols isolated from sponges belonging to very different orders, such as Cittachyra, Hippospongia, Ircinia, and Polymastia. 

Kobayashi, M., Kobayashi, K., Ramana, V., and Rao, C.V.L. (1991a) Marine sterols Part 20. Polyhydroxysterols of the soft corals of the Andaman and Nicobar coasts. Part 4. Andamansterol and nicobarsterol, novel sterols with 3,9,11,21-tetrahydroxylated, and ll,21-epoxy-9,ll-secosteroid skeletons, from a Sclerophytum sp. of soft coral. X-ray molecular structure of andamansterol. J. Chem. Soc. Perkin Trans. I, 493-497. 

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