Oxygen catalyzed

The oxidation of isocyanides to isocyanates with oxygen, catalyzed by Ni(CNR)4 or Ni(CjHi2)2. has been known for some time 106). One can now postulate on the basis of these data that catalysis is being accomplished via oxygen coordination to the metal. 

Nojiri H, J-W Nam, M Kosaka, K-I Morii, T Takemura, K Furihata, H Yamane, T Omori (1999) Diverse oxygenations catalyzed by carbazole l,9a-dioxygenase from Pseudomonas sp. strain CA 10. J Bacterial 181 3105-3113. 

Adam, W., Lazarus, M., Boss, B. et al. (1997) Enzymic resolution of chiral 2-hydroxy carboxylic acids by enantioselective oxidation with molecular oxygen catalyzed by the glycolate oxidase from spinach (Spinacia oleracea). The Journal of Organic Chemistry, 62 (22), 7841-7843. 

Under aerobic conditions, aerobic bacteria has so far been only found in studies capable of reducing azo compounds and produce aromatic amines by specific oxygen-catalyzed enzymes called azo reductases. These aerobic bacteria could grow with mostly simple azo compounds as sole source of carbon and energy and under strict aerobic conditions by using a metabolism that started with reductive cleavage of the azo linkage. 

Wacker (1) A general process for oxidizing aliphatic hydrocarbons to aldehydes or ketones by the use of oxygen, catalyzed by an aqueous solution of mixed palladium and copper chlorides. Ethylene is thus oxidized to acetaldehyde. If the reaction is conducted in acetic acid, the product is vinyl acetate. The process can be operated with the catalyst in solution, or with the catalyst deposited on a support such as activated caibon. There has been a considerable amount of fundamental research on the reaction mechanism, which is believed to proceed by alternate oxidation and reduction of the palladium ... 

E. F. J. de. Vries, L. Ploeg, M. Colao, J. Brussee, A. van der Gen, Enantioselective Oxidation of Aromatic Ketones by Molecular Oxygen, Catalyzed by Chiral Monoaza-Crown Ethers , Tetrahedron Asymmetry 1995, 6, 1123-1132. 

M. Hasan, M. Musawir, P. N. Davey, I. V. Kozhevnikov Oxidation Of Primary alcohols to aldehydes with Oxygen Catalyzed by Tetra-n-propyl ammonium perruthenate,, J. Mol. Catal. A Chem. 180 (2002) 77-84. 

In the presence of oxygen, the lifetimes of both radical ion pairs (i.e., ZnP +-C6o and ZnP +-H2P-C6o ) are decreased significantly due to oxygen-catalyzed back-electron transfer (BET) processes between Ceo and ZnP " [76]. The catalytic participation of O2 in an intramolecular BET between Ceo and ZnP + in ZnP-linked Ceo is depicted in Scheme 6 [76]. The intermolecular ET from Ceo to O2 is facilitated by the partial coordination of O2 to ZnP " in the transient state (denoted as in Scheme 6) [76]. Consequently, the one-electron reduction potential of the resulting 02 is shifted toward positive values, namely in favor of the ET event. The strong coordination of O2 to Zn(II) ion has been well established [77]. The complexation is then followed by a rapid intramolecular... 

Oxidation of 2-Butene with Oxygen, Catalyzed by Bis (1-methyl-2-acetoxypropyl)selenide. This reaction was conducted at 120°C. and total pressures from 80 to 400 p.s.i.g. and oxygen partial pressures from 5 to 40 p.s.i.g. 

Typical examples of liquid-phase oxidation with molecular oxygen catalyzed by heteropoly compounds are listed in Table XXVI. Introduction of Vs + or... 

Liquid-Phase Oxidation Reactions with Molecular Oxygen Catalyzed by Heteropoly Compounds Reaction Catalyst Temp. (K) Ref. 

Liquid-Phase Oxidations with Hydrogen Peroxide and Molecular Oxygen Catalyzed by Polyoxometalate-Based Compounds... 

In the synthesis of a series of cyclic aromatic disulfide oligomers using oxidative coupling of dithiols with oxygen catalyzed by copper salts and an amine, an effective, easy, and rapid method for the synthesis of macrocyclic aromatic disulfide oligomer from 4,4/-oxybis(benzenethiol) by cyclodepoly-... 

W Adam, W Boland, J Hartmann-Schreier, H-U Humpf, M Lazarus, A Saffert, CR Saha-Moller, P Schreier. a Hydroxylation of carboxylic acids with molecular oxygen catalyzed by the a oxidase of peas (Pisum sativum) a novel biocatalytic synthesis of enantiomerically pure (R)-2-hydroxy acids. J Am Chem Soc 120 11044— 11048, 1998. 

Tetrahydroisoquinolines have been oxidized to 3,4-dihydroisoquinolines using cerric ammonium nitrate <95SC(25)2591>, as well as by using molecular oxygen catalyzed by cuprous chloride <95H(41)773>. 3,4-dihydroisoquinolines have been used in the synthesis of l-substituted-2-aryltetrahydroisoquinolines <95SC(25)1817>, and in the synthesis of 1 -N-arylaminomethylene derivatives of 8-azasteroids (Scheme 41) <95KGS266>. 

Moreover, when 02 is formed in the hydrophobic stage, vitamin E (20, tocopherol) creates a hydrogen atom. The hydrogen peroxide formed is decomposed to water and molecular oxygen catalyzed by catalase enzyme (protein containing Fe-complex), and the oxidized vitamin E radical is reduced to vitamin E again by vitamin C (eq. 1.10)... 

While there is controversy as to whether or not this Cellulose species exists, experimental evidence for the Cellulose species was obtained by Price et al.,60 who suggested that it could be a free radical in nature. At lower temperatures, oxygen plays a dominant role in cellulose degradation, and pyrolysis is faster in an oxidative atmosphere than in an inert one.61 Oxygen catalyzes the formation of both volatiles and char-promoting reactions.62 At higher temperatures, the degradation products are little affected.61... 

Most enzymatic oxygenations catalyzed by monooxygenases require the presence of both molecular oxygen and an electron donor, usually referred to as the cofactor. These oxygenations are described by the general equation,... 

Epoxy alcohols. A few years ago Mihelich1 was granted a patent for preparation of epoxy alcohols by photooxygenation of alkenes in the presence of titanium or vanadium catalysts. Adam et al.2 have investigated this reaction in detail and find that Ti(IV) isopropoxide is the catalyst of choice for epoxidation of di-, tri-, and tetrasubstituted alkenes, acyclic and cyclic, to provide epoxy alcohols. When applied to allylic alcohols, the reaction can be diastereo- and enantioselective. The reaction actually proceeds in two steps an ene reaction to provide an allylic hydroperoxide followed by intramolecular transfer of oxygen catalyzed by Ti(0-i-Pr)4. The latter step is a form of Sharpless epoxidation and can be highly stereoselective. 

Figure 12.5 Proposed mechanism for the cyclic oxidation of primary alcohols by molecular oxygen catalyzed by a photodriven model of native oxidoreductase - the antimony(V) oxo...

Ortiz de Montellano PR, Choe YS, DePillis G et al (1987) Structure-mechanism relationships in hemoproteins. Oxygenations catalyzed by chloroperoxidase and horseradish peroxidase. J Biol Chem 262 11641-11646... 

Figure 29 A common pathway of trichothecene biosynthesis. FPP is cyclized to TDN (125) by a cyclase encoded by Tri5. In the biosynthesis of both Fusarium trichothecenes and non-Fusarium trichothecenes, three oxygenations catalyzed by a CYP encoded by Tri4 follow to yield ITdiol (128).

Various porphyrin compounds such as NFevOEP are known.62 The i Fe=N) stretching frequency of 853 cm-1 is lower than that of the Cr and Mn analogues the nitrido Fev complex is stable only at very low temperature ( 30 K). It is widely accepted that one of the intermediate species in the catalytic cycle of cytochrome P-450 (see later) contains pentavalent iron. The reduction of an R3CFev moiety is an accepted part of the mechanism of dismutation of hydrogen peroxide to water and oxygen catalyzed by catalase. 

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