601-54-7Relevant articles and documents
Modification of the Swern Oxidation: Use of a Soluble Polymer-Bound, Recyclable, and Odorless Sulfoxide
Harris, Joanna M.,Liu, Yaoquan,Chai, Shengyong,Andrews, Mark D.,Vederas, John C.
, p. 2407 - 2409 (1998)
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Cr(VI) Oxidation of Cholesterol—A Kinetic Study Using N-Cetylpicolinium Dichromates, A Class of Novel Phase Transfer Oxidants
Priyadarshini,Guru,Ds,Dash
, p. 147 - 154 (2019)
Abstract: Kinetic study of cholesterol oxidation has been studied using a series of N-cetylpicolinium dichromates (CPDC), a class of phase transfer oxidants, in acetic acid medium under first order conditions with respect to oxidant. Rate constants were calculated in the temperature range 290–300 K. The kinetics was followed spectrophotometrically; cholest-5-en-3-one is found to be the only oxidation product. Unlike the previously reported lipopathic oxidant containing cetyltrimethylammonium ions, these oxidants show a direct variation of rate with the oxidant concentration ruling out any reversed micellar organization of the oxidant molecules. From the experimental data formation of an unstable cyclic transition state followed by intra-molecular proton transfer has been proposed. Solvent isotope effect for the cholesterol oxidation (Formula Presented.) indicated a carbon-hydrogen cleavage rather than a carbon-carbon cleavage. Variation of solvent polarity is found to impose a remarkable impact on the rate of oxidation: more polar reaction environment favours the oxidation by β-CPDC oxidant to a higher extent, compared to the other two oxidant isomers, α-CPDC and γ-CPDC.
Synthesis and characterisation of steroidal inhibitors of α-amylase, α-glucosidase and oxidative species
Fanyana, Mthunzi,Habila, James D.,Modise, Johannes S.,Ndukwe, Iloegbulam G.,Okoli, Bamidele J.,Olaniyan, Olugbemi T.,Rachael, Ayo G.
, p. 411 - 422 (2019)
BACKGROUND: Management of cellular metabolism and blood glucose levels are significant in the treatment of diabetes mellitus and oxidative diseases. Consequently, steroid and peptide hormone-based drugs such as methylprednisolone and insulin have been the most effective and safe methods of treatment. OBJECTIVE: Our study investigated the digestive enzymes and oxidative species inhibitory potentials of seven derived biologically important steroids. METHODS: Syntheses of the steroidal inhibitors (SIs) were accomplished by functional group transformations. Characterisation of SIs was achieved by spectroscopic techniques; followed by in-vitro enzyme and oxidative suppression studies. RESULTS: NMR data revealed the presence of a steroid backbone, azomethine, carbonyl, and oxymethine peaks while the vibrational bands were further confirmed by the FTIR. The enzyme suppression activities of the SIs were influenced by the presence of histidine residue and free proton groups. However, the antioxidant activities were solely dependent on the free proton groups on the steroid backbone or the number of the histidine side chain. SIs [3, 4, and 6] exhibited a potent inhibitory effect on the enzyme activities compared to SIs [1, 2, 5, and 7], while a potent antioxidant activity was reported by SI [5]. CONCLUSIONS: Generally, SIs with hydroxyl and α-amino acid functionalities have a strong affinity for the enzyme active site than the substrate; hence, the hydrolysis of the α-1,4-glycosidic bonds of saccharide was hindered. In vivo administration of SIs [3, 4, and 6] should take into cognizance the suppression effect at doses ≤939.49 μg/mL as well as the potential to induce abnormal bacterial fermentation of undigested carbohydrates in the colon at high concentration.
Alteration of Membrane Cholesterol Content Plays a Key Role in Regulation of Cystic Fibrosis Transmembrane Conductance Regulator Channel Activity
Cui, Guiying,Cottrill, Kirsten A.,Strickland, Kerry M.,Mashburn, Sarah A.,Koval, Michael,McCarty, Nael A.
, (2021/06/27)
Altered cholesterol homeostasis in cystic fibrosis patients has been reported, although controversy remains. As a major membrane lipid component, cholesterol modulates the function of multiple ion channels by complicated mechanisms. However, whether cholesterol directly modulates cystic fibrosis transmembrane conductance regulator (CFTR) channel function remains unknown. To answer this question, we determined the effects of changing plasma membrane cholesterol levels on CFTR channel function utilizing polarized fischer rat thyroid (FRT) cells and primary human bronchial epithelial (HBE) cells. Treatment with methyl-β-cyclodextrin (MβCD) significantly reduced total cholesterol content in FRT cells, which significantly decreased forskolin (FSK)-mediated activation of both wildtype (WT-) and P67L-CFTR. This effect was also seen in HBE cells expressing WT-CFTR. Cholesterol modification by cholesterol oxidase and cholesterol esterase also distinctly affected activation of CFTR by FSK. In addition, alteration of cholesterol increased the potency of VX-770, a clinically used potentiator of CFTR, when both WT- and P67L-CFTR channels were activated at low FSK concentrations; this likely reflects the apparent shift in the sensitivity of WT-CFTR to FSK after alteration of membrane cholesterol. These results demonstrate that changes in the plasma membrane cholesterol level significantly modulate CFTR channel function and consequently may affect sensitivity to clinical therapeutics in CF patients.
NiH-Catalyzed Proximal-Selective Hydroamination of Unactivated Alkenes
Jeon, Jinwon,Lee, Changseok,Seo, Huiyeong,Hong, Sungwoo
supporting information, p. 20470 - 20480 (2020/11/27)
Reported herein is a modular, NiH-catalyzed system capable of proximal-selective hydroamination of unactivated alkenes with diverse amine sources. The key to the successful implementation of this approach is the promotion of NiH insertion into even highly substituted olefins via coordination of the bidentate directing group to the nickel complex. A wide range of primary and secondary amines can be installed in both internal and terminal unactivated alkenes with excellent regiocontrol under the optimized reaction conditions. This protocol is flexible and general for the preparation of a variety of valuable β- and γ-amino acid building blocks that would otherwise be difficult to synthesize. The utility of this transformation was further demonstrated by the site-selective late-stage modification of complex and medicinally relevant molecules. Combined experimental and computational studies illuminate the detailed reaction mechanism.
