114246-94-5Relevant articles and documents
Chicoye et al.
, p. 335,337, 339 (1968)
A one-step synthesis of 6β-hydroxy-Δ4-3-ketones. Novel oxidation of homoallylic sterols with permanganate ion
Parish, Edward J.,Li, Shengrong
, p. 5665 - 5666 (1996)
-
Manganese (III) acetate dihydrate catalyzed aerobic epoxidation of unfunctionalized olefins in fluorous solvents
Ravikumar,Barbier, Francis,Begue, Jean-Pierre,Bonnet-Delpon, Daniele
, p. 7457 - 7464 (1998)
Manganese(III) acetate dihydrate is used as a catalyst for the epoxidation of various olefins with molecular oxygen/pivalaldehyde as an oxidant in perfluoro-2-butyltelrahydrofuran. Various types of olefins, including substituted styrenea, stilbenes and cyclic and acyclic alkenes were epoxidized in excellent yields at 25°C. The reaction is stereodependent. Regioselectivity is observed on epoxidation of limonene. Mono- and disubstituted olefins show interesting dichotomy in their reactivity in fluorous solvents such as perfluoro-2-butyltetrahydrofuran and 1,1,1,3,3,3- hexafluoro-2-propanol.
-
Becker,Wallis
, p. 353,358 (1955)
-
Rowland,Nace
, p. 2833,2835 (1960)
-
Chakravorty,Levin
, p. 2317,2320 (1942)
-
Molybdenum catalyzed β-selective epoxidation of cholesterol esters with molecular oxygen
Kantam,Santhi
, p. 961 - 964 (1994)
Molybdenyl(IV) acetylacetonate catalyses the conversion of various cholesterol esters into the corresponding β-epoxides in good yields with the combined use of molecular oxygen and i-butyraldehyde at room temperature.
The regio- and stereo-selective epoxidation of alkenes with methyl trioxorhenium and urea-hydrogen peroxide adduct
Boehlow, Todd R.,Spilling, Christopher D.
, p. 2717 - 2720 (1996)
-
Oxidation of Cholesterol by Heating
Osada, Kyoichi,Kodama, Takehiro,Yamada, Koji,Sugano, Michihiro
, p. 1198 - 1202 (1993)
Oxidation of pure cholesterol during heating in an air oven at high temperature was studied.Cholesterol was virtually stable during heating at 100 deg C for 24 h but was unstable at temperature above 120 deg C.In the heated choleaterol preparations, a number of oxidized derivatives were detected by a combination of thin-layer chromatography and capillary gas chromatography-mass spectrometry.Major oxidized sterols were 7α-hydroxycholesterol, 7β-hydroxycholesterol, 5α-epoxycholesterol, 5β-epoxycholesterol, cholestanetriol, and 7-ketocholesterol.Various oxidized cholesterol derivatives were produced during heating above 120 deg C within a relatively short time (1h).The composition of the oxidized products differed depending on temperature and time of heating.When cholesterol was heated at 150 deg C, the production of oxidized cholesterol was maximum, and 7-ketocholesterol was the most predominant oxidized product.Heating at 120 deg C also produced oxidized cholesterol to some extent, whereas only marginal amounts of oxidized cholesterols were produced at 100 deg C and at 200 deg C cholesterol was almost decomposed in a short time.
-
Paige
, p. 437,441 (1943)
-
-
Uschakow,Madajewa
, (1939)
-
Effect of Eleven Antioxidants in Inhibiting Thermal Oxidation of Cholesterol
Xu, Guihua,Liu, Donghong,Zhao, Gongling,Chen, Shiguo,Wang, Jun,Ye, Xingqian
, p. 215 - 225 (2016)
Eleven antioxidants including nine phenolic compounds (rutin, quercetin, hesperidin, hesperetin, naringin, naringenin, chlorogenic acid, caffeic acid, ferulic acid), vitamin E (α-tocopherol), and butylated hydroxytoluene (BHT) were selected to investigate their inhibitory effects on thermal oxidation of cholesterol in air and lard. The results indicated that the unoxidized cholesterol decreased with heating time whilst cholesterol oxidation products (COPs) increased with heating time. The major COPs produced were 7α-hydroxycholesterol, 7β-hydroxycholesterol, 5,6β-epoxycholesterol, 5,6α-epoxycholesterol, and 7-ketocholesterol. When cholesterol was heated in air for an hour, rutin, quercetin, chlorogenic acid, and caffeic acid showed a strong inhibitory effect. When cholesterol was heated in lard, caffeic acid, quercetin, and chlorogenic acid demonstrated inhibitory action during the initial 0.5 h (p a high flame is recommended. If baking or deep fat frying food in oil, it is best to limit cooking time to within 0.5 h.
A VERSATILE METHOD FOR PREPARATION OF O-ALKYLPEROXICARBONIC ACIDS: EPOXIDATION WITH ALKYLOXYCARBONYLIMIDAZOLES AND HYDROGEN PEROXIDE
Tsunokawa, Youko,Iwasaki, Shigeo,Okuda, Shigenobu
, p. 2113 - 2116 (1982)
A variety of O-alkylperoxycarbonic acids (2) were conveniently prepared in situ by utilizing alkyloxycarbonylimidazoles (1) as their precursors.Epoxidation of alkenes with such peroxy-acids was studied and their reactivities were compared with those of peroxycarboxylic acids.
H-Atom Abstraction vs Addition: Accounting for the Diverse Product Distribution in the Autoxidation of Cholesterol and Its Esters
Zielinski, Zosia A. M.,Pratt, Derek A.
, p. 3037 - 3051 (2019/02/19)
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.
Chemoselective epoxidation of cholesterol derivatives on a surface-designed molecularly imprinted Ru-porphyrin catalyst
Muratsugu, Satoshi,Baba, Hiroshi,Tanimoto, Tatsuya,Sawaguchi, Kana,Ikemoto, Satoru,Tasaki, Masahiro,Terao, Yosuke,Tada, Mizuki
supporting information, p. 5114 - 5117 (2018/05/26)
A new molecularly imprinted Ru-porphyrin complex catalyst on a SiO2 support was designed, prepared, and characterized in a step-by-step manner for the C5C6 epoxidation of cholesterol derivatives. High chemoselectivity for the C5C6 epoxidation of cholesterol derivatives without protecting the 3-position OH group and other oxidizable functional groups was achieved on the molecularly imprinted catalyst.
