21273-02-9Relevant academic research and scientific papers
Mechanism of alcohol oxidations by anionic peroxomolybdenum complexes
Campestrini, Sandro,Di Furia, Fulvio
, p. 5119 - 5130 (1994)
The rates of oxidation of a series of primary and secondary alcohols to the corresponding carbonyl compounds by seven anionic peroxomolybdenum complexes, i.e [MoO(O2)2(C5H4NCOO)]- (BU4N+ (1a), [MoO(O2)2(C5H4NOCOO)]- (Bu)4N+ (2a) and [MoO(O2)2(X-C6H4COO)]- (Bu)4N+ (X = H, p-NH2, p-OMe, m-Cl, p-NO2) (3a-e), have been measured under various experimental conditions. Different kinetic behaviors are exhibited by the various oxidants. In particular, different rate laws, activation parameters and kinetic isotope effects are found. Despite such differences a common general mechanistic scheme can be proposed, involving the association of the substrate to a free or releasable coordination site of the peroxocomplexes, leading to an intermediate present in a low, steady-state concentration. From such an alkoxo intermediate the carbonyl product is obtained through a series of steps whose nature is suggested only by indirect evidence. Two subsequent electron transfers to the oxidant from the coordinated alkoxo compound are considered the most likely mechanism.
Preparation of NADH, NADPH and the Corresponding 4S-Isomers All with Substantial Specific Activities
Ichinose, Koji,Leeper, Finian J.,Battersby, Alan R.
, p. 1213 - 1216 (2007/10/02)
Methods are developed for the enzymic preparation of NADH, NADPH and the corresponding 4S-isomers, all stereospecifically labelled and of specific activities amply high enough for sensitive labelling experiments.Sodium borotritiide provides the tritium for all four cofactors.
CYCLOHEXANONE OXYGENASE: STEREOCHEMISTRY, ENANTIOSELECTIVITY, AND REGIOSELECTIVITY OF AN ENZYME-CATALYZED BAEYER-VILLIGER REACTION.
Schwab,Li,Thomas
, p. 4800 - 4808 (2007/10/04)
Cyclohexane oxygenase, from Acinetobacter NCIB 9871, has been incubated with (2S,6S)- left bracket 2,6-**2H//2 right bracket - and (2R)- left bracket 2-**2H//1 right bracket cyclohexanone. The resulting labeled epsilon -caprolactone (2-oxepanone) samples were degraded to 1-pentanol, which was esterified by using ( minus )-camphanyl chloride. Analysis of the camphanates by deuterium NMR spectroscopy, using Eu(dpm)//3, showed that the conversion of ketone to lactone had in each case proceeded with complete retention of configuration at the migrating carbon center. A similar degradation of (2R)- left bracket 2-**2H//1 right bracket cyclohexanone itself showed that reduction of left bracket 2-**2H//1 right bracket -cyclohex-2-enone by Beauveria bassiana ATCC 7159 is also completely stereoselective. A method has been developed for assessing the enantioselectivity of enzymes toward racemic substrate mixtures.
On the Solvolysis of 2-Cyclohexenyl 3,5-Dinitronbenzoate and p-Nitrobenzoate in Aqueous Acetone. Introduction of Acyl-Oxygen Cleavage by Basic Buffer Systems
Kantner, Steven S.,Humski, Kresimir,Goering, Harlan L.
, p. 1693 - 1697 (2007/10/02)
Solvolysis of α- and β-deuterium-labeled 2-cyclohexenyl 3,5-dinitrobenzoate (1-ODNB) and p-nitrobenzoate (1-OPNB) in 60percent aqueous acetone containing diisopropylethylamine (to protect initially formed product from subsequent acid-catalyzed allylic rea
Tin(IV) Ethoxide-catalysed Hydride Transfer from Alcohols to Carbonyl Compounds
Casiraghi, Giovanni,Casnati, Giuseppe,Sartori, Giovanni,Zanafredi, Girolamo T.
, p. 407 - 411 (2007/10/02)
In aprotic, apolar solvents tin(IV) ethoxide has been proved to be an efficient catalyst for the selective hydride transfer from alcohols to carbonyl compounds.Primary, secondary, and benzyl alcohols have shown hydride-donating ability, and this ability decreases in the order benzylsecondaryprimary.The mechanism of hydride transfer from 1-phenylethanol to cyclohexanone has been investigated.Catalysis is inferred to proceed in the following order: (a) alcoholysis of Sn(IV)ethoxide to form a mixed metal alkoxide, (b) co-ordination of the acceptor to the metal, (c) direct hydride transfer from the alkoxide moiety to the co-ordinated carbonyl compound and loss of the active catalyst.The kinetic isotope effetc measurements and other data suggest that step (c) is the rate-determining step of the reaction.
