Formation of Samin Diastereomers by Acid-Catalyzed Transformation of Sesamolin with Hydrogen Peroxide

2020 ◽  
Vol 68 (23) ◽  
pp. 6430-6438
Author(s):  
Hsin-Ya Tsai ◽  
Wei-Ju Lee ◽  
I-Hsuan Chu ◽  
Wei-Ching Hung ◽  
Nan-Wei Su
Keyword(s):  
Hydrogen Peroxide ◽  
Acid Catalyzed

Acid-catalyzed rearrangement of hydroperoxides. II. Phenylcycloalkyl hydroperoxides

1968 ◽  
Vol 46 (9) ◽  
pp. 1561-1570 ◽  
Author(s):  
Glenn H. Anderson ◽  
James G. Smith
Keyword(s):  
Hydrogen Peroxide ◽  
Ferrous Sulfate ◽  
Phenyl Group ◽  
Ring Expansion ◽  
Steric Interaction ◽  
Ring Strain ◽  
Mineral Acids ◽  
Acid Catalyzed

The acid-catalyzed rearrangement of 1-phenylcycloalkyl hydroperoxides has been investigated using the cyclohexyl, cyclopentyl, and cyclobutyl compounds. Evidence was sought for rearrangement of the cycloalkyl group in competition with migration of the phenyl group during the reaction. Such a rearrangement would result in ring expansion of the cycloalkyl group to give, ultimately, products formed by cycloalkyl ring opening.No evidence for such a reaction was found in the case of 1-phenylcyclohexyl hydroperoxide; only the expected products, phenol and cyclohexanone, were detected. However, rearrangement of 1-phenylcyclopentyl hydroperoxide gave, besides the expected phenol and cyclopentanone, significant amounts of the ring-opened compound 4-hydroxyvalerophenone as its acetate. A second product, 1-phenylcyclopentene, arose by elimination of hydrogen peroxide from the hydroperoxide.1-Phenylcyclobutyl hydroperoxide proved to undergo ring expansion with great facility. Only the ring expanded products, 2-phenyl-2-tetrahydrofuryl hydroperoxide and its corresponding peroxide, could be isolated in the treatment of 1-phenylcyclobutanol with hydrogen peroxide using catalytic amounts of mineral acids. However, in the absence of catalysts, 1-phenylcyclobutyl hydroperoxide was formed in detectable amounts and its presence was demonstrated by decomposition with ferrous sulfate to butyro-phenone and 1,6-dibenzoylhexane.It seems reasonable that ring strain is the factor promoting the ring expansion of 1-phenylcyclobutyl hydroperoxide. In the case of 1-phenylcyclopentyl hydroperoxide, it is suggested that the steric interaction of the ortho hydrogens of the phenyl group with the cyclopentyl ring protons has the effect of slowing the migration of the phenyl group sufficiently that alkyl migration can occur to give the observed ring-opened products.

The Theodorakis Synthesis of (–)-Jiadifenolide

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Hydrogen Peroxide ◽  
Carboxylic Acid ◽  
Aldol Condensation ◽  
University Of California ◽  
Oxidative Rearrangement ◽  
Promote Neurite Outgrowth ◽  
Starting Point ◽  
Jones Reagent ◽  
Acid Catalyzed ◽  
The University

There has recently been a great deal of interest in the synthesis of natural products that promote neurite outgrowth. Emmanuel A. Theodorakis of the University of California, San Diego described (Angew. Chem. Int. Ed. 2011, 50, 3672) the preparation of one of the most potent (10 nM) of these, (–)-jiadifenolide 3. Fittingly, a key transformation en route to this highly oxygenated seco-prezizaane was the oxidative rearrangement of 1 to 2. The starting point for the synthesis was the commercially available diketone 4. Allylation followed by addition to 5 gave the prochiral triketone 6. Enantioselective aldol condensation following the Tu/Zhang protocol then delivered the bicyclic enone 7. Alkylation to give 8 proceeded with high diastereoselectivity, perhaps controlled by the steric bulk of the silyloxy group. Exposure of the protected ketone to the McMurry reagent PhNTf2 gave the enol triflate 9, which smoothly carbonylated to the lactone 10. Epoxidation with alkaline hydrogen peroxide followed by oxidation gave the carboxylic acid, which spontaneously opened the epoxide, leading to the bis lactone 1. With 1 in hand, the stage was set for the key oxidative rearrangement to 2. It was envisioned that epoxidation would generate the cis-fused 11, which on oxidation would undergo acid-catalyzed elimination to give 12. The newly freed OH would then be in position to engage the lactone carbonyl, leading to 2. In the event, oxidation of the epoxide with the Dess-Martin reagent required sonication for 2 h. The rearranged lactone, even though it was susceptible to further oxidation, was secured in 38% overall yield from 1. After hydrogenation and protection, preparation of the enol triflate 13 from the congested cyclopentanone necessitated the use of the more reactive Comins reagent. Hydrogenation of the trisubstituted alkene from coupling with Me3Al then required 90 atmospheres of H2 overpressure. Hydroxylation of the lactone 14 with the Davis oxaziridine followed by further oxidation to the ketone with the Jones reagent and deprotection then completed the synthesis of (–)-jiadifenolide 3.

Organic hydroperoxide formation in the acid-catalyzed heterogeneous oxidation of aliphatic alcohols with hydrogen peroxide

RSC Advances ◽  
2014 ◽  
Vol 4 (38) ◽  
pp. 19716-19724 ◽  
Author(s):  
Qifan Liu ◽  
Weigang Wang ◽  
Ze Liu ◽  
Tianhe Wang ◽  
Lingyan Wu ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Aliphatic Alcohols ◽  
Heterogeneous Oxidation ◽  
Organic Hydroperoxide ◽  
Hydroperoxide Formation ◽  
Acid Catalyzed

We present detailed mechanisms for the formation and degradation of organic hydroperoxide during the acid-catalyzed heterogeneous oxidation of aliphatic alcohols with hydrogen peroxide.

scholarly journals Degradation of aflatoxin in maize using Ferulic acid (phydroxy-3-methyl cinnamic acid) catalyzed by Hydrogen peroxide

2020 ◽  
Vol 1 (1) ◽  
pp. 1-17
Author(s):  
Nicholas M. Jacob ◽  
Shem O. Wandiga ◽  
David K. Kariuki ◽  
Vincent O. Madadi
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Ferulic Acid ◽  
High Performance ◽  
Degradation Process ◽  
Hammer Mill ◽  
Fluorescence Detector ◽  
First Order Kinetics ◽  
Acid Catalyzed ◽  
Pre Treatment

Purpose: The study aimed to determine the rate of degradation of aflatoxin in contaminated maize using ferulic acid catalyzed by hydrogen peroxideMethodology: 100 g of dried maize grain was grounded using a laboratory hammer mill and divided into 2 portions of 50 g each. 20 g sample was taken per portion and treated with 100 mL solution of methanol and deionized water in the ration of 8:1, 50 mL of Acetonitrile, 1 g NaCl and 4 g of anhydrous magnesium sulphate, then blended at 120 RPM for 30 min. Aflatoxin content in each extract was analysed using enzyme-linked immunoassay test kits and confirmed using high performance liquid chromatography (HPLC) coupled with fluorescence detector. Further experiments tested the effect of coating, size, concentration, catalyst and reaction time on degradation of aflatoxin in maize. Data analysis was conducted using SPSS and Microsoft excel.Findings: Four-hour treatment of contaminated maize with 0.5 mM ferulic acid reduced aflatoxin by 91.0% for whole maize, 90.5% for dehulled maize and 90.9% for ground maize. Addition of 20 mL of 0.5% hydrogen peroxide to the reaction mixtures increased degradation of aflatoxin load to 99.0% for whole maize, 99.1% for dehulled maize and 99.1% for ground maize within 4-hour reaction time. The rate of decontamination followed first order kinetics with R2 values of 0.919, 0.916 and 0.930 for the whole maize, dehulled maize, ground maize, respectively and achieved degradation half-lives of 43.59, 41.26 and 39.84 minutes in the same order.Unique contribution to theory, practice and policy: Ferulic acid combined with hydrogen peroxide is an effective degrader of aflatoxin in maize. The rate degradation is dependent on the nature of maize pre-treatment, the concentration of ferulic acid, and the catalyst. Ferulic acid and hydrogen peroxide reacted with the lactone ring of the coumarin moity of aflatoxin. Recommendations; Further studies on degradation of aflatoxin in maize should elucidate the pathways and metabolites formed in the ferulic acid degradation process and determine their toxicities

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