Manganese-(II) and (III)-mediated free-radical cyclisation of alkenes, β-keto esters and molecular oxygen

1993 ◽  
pp. 609-616 ◽  
Author(s):  
Takashi Yamada ◽  
Yoko Iwahara ◽  
Hiroshi Nishino ◽  
Kazu Kurosawa
Keyword(s):  
Free Radical ◽  
Molecular Oxygen ◽  
Keto Esters

Manganese(III)-based oxidative free-radical reaction of α-allyl-β-keto ester with molecular oxygen

1993 ◽  
Vol 34 (52) ◽  
pp. 8509-8512 ◽  
Author(s):  
Takashi Ohshima ◽  
Mikiko Sodeoka ◽  
Masakatsu Shibasaki
Keyword(s):  
Free Radical ◽  
Molecular Oxygen ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Keto Ester

ChemInform Abstract: Enantioselective Photooxygenation of β-Keto Esters by Chiral Phase-Transfer Catalysis Using Molecular Oxygen.

ChemInform ◽  
2013 ◽  
Vol 44 (9) ◽  
pp. no-no
Author(s):  
Mingming Lian ◽  
Zhi Li ◽  
Yuanchun Cai ◽  
Qingwei Meng ◽  
Zhanxian Gao
Keyword(s):  
Molecular Oxygen ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Chiral Phase ◽  
Keto Esters

scholarly journals Free Radical Mediated Oxidative Degradation of Carotenes and Xanthophylls

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1038 ◽  
Author(s):  
Raphael C. Mordi ◽  
Olabisi T. Ademosun ◽  
Christiana O. Ajanaku ◽  
Ifedolapo O. Olanrewaju ◽  
John C. Walton
Keyword(s):  
Excited State ◽  
Free Radical ◽  
Vitamin A ◽  
Molecular Oxygen ◽  
Oxidative Degradation ◽  
Chain Structure ◽  
Ring Structure ◽  
Peroxyl Radicals ◽  
Chemical Structures ◽  
Excited State Quenching

This article reviews the excited-state quenching, pro-vitamin A activity and anticarcinogenicity of carotenes and xanthophylls in relation to their chemical structures. Excited-state quenching improved with the length of the conjugated chain structure. Pro-vitamin A activity was dependent on the presence of at least one beta-ionyl ring structure. The effectiveness of carotenoids as antioxidants depended on their ability to trap peroxyl radicals with production of resonance-stabilized carotenyl radicals. The products identified from oxidations of carotenes and xanthophylls with molecular oxygen and other oxidizing agents are presented. The free radical-mediated mechanisms that have been proposed to account for the different classes of products are reviewed.

scholarly journals Novel Effect of Zinc Nitrate/Vanadyl Oxalate for Selective Catalytic Oxidation of α-Hydroxy Esters to α-Keto Esters with Molecular Oxygen: An In Situ ATR-IR Study

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1281 ◽  
Author(s):  
Yongwei Ju ◽  
Zhongtian Du ◽  
Chuhong Xiao ◽  
Xingfei Li ◽  
Shuang Li
Keyword(s):  
Catalytic Activity ◽  
Catalytic Oxidation ◽  
Molecular Oxygen ◽  
Aerobic Oxidation ◽  
Value Added ◽  
Attenuated Total Reflection ◽  
Reaction Conditions ◽  
Keto Esters ◽  
Selective Catalytic Oxidation ◽  
Hydroxy Esters

Selective oxidation of α-hydroxy esters is one of the most important methods to prepare high value-added α-keto esters. An efficient catalytic system consisting of Zn(NO3)2/VOC2O4 is reported for catalytic oxidation of α-hydroxy esters with molecular oxygen. Up to 99% conversion of methyl DL-mandelate or methyl lactate could be facilely obtained with high selectivity for its corresponding α-keto ester under mild reaction conditions. Zn(NO3)2 exhibited higher catalytic activity in combination with VOC2O4 compared with Fe(NO3)3 and different nitric oxidative gases were detected by situ attenuated total reflection infrared (ATR-IR) spectroscopy. UV-vis and ATR-IR results indicated that coordination complex formed in Zn(NO3)2 in CH3CN solution was quite different from Fe(NO3)3; it is proposed that the charge-transfer from Zn2+ to coordinated nitrate groups might account for the generation of different nitric oxidative gases. The XPS result indicate that nitric oxidative gas derived from the interaction of Zn(NO3)2 with VOC2O4 could be in favor of oxidizing VOC2O4 to generate active vanadium (V) species. It might account for different catalytic activity of Zn(NO3)2 or Fe(NO3)3 combined with VOC2O4. This work contributes to further development of efficient aerobic oxidation under mild reaction conditions.

Free-radical chain oxidation of rat red blood cells by molecular oxygen and its inhibition by α-tocopherol

1987 ◽  
Vol 258 (2) ◽  
pp. 373-380 ◽  
Author(s):  
Masayuki Miki ◽  
Hiroshi Tamai ◽  
Makoto Mino ◽  
Yorihiro Yamamoto ◽  
Etsuo Niki
Keyword(s):  
Free Radical ◽  
Red Blood Cells ◽  
Molecular Oxygen ◽  
Blood Cells ◽  
Radical Chain ◽  
Chain Oxidation ◽  
Radical Chain Oxidation

Facile Synthesis of α-Keto Esters via A Free Radical Acylation Approach

Synlett ◽  
1997 ◽  
Vol 1997 (Sup. I) ◽  
pp. 475-476 ◽  
Author(s):  
Sunggak Kim ◽  
Joo-Yong Yoon ◽  
Ill Lee
Keyword(s):  
Free Radical ◽  
Facile Synthesis ◽  
Keto Esters
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