Bromamine-B , oxidation

Ruthenium(in) catalyses the oxidative decarboxylation of n-butyric acid and isobutyric acid by ceric sulfate in aqueous acid. A mechanism for the Ru(III)-catalysed oxidation of o-hydroxybenzoic acid by an acidic solution of bromamine-B (PhS02-NNaBr, BAB) has been proposed based on a kinetic smdy. An ionic mechanism is suggested for the ruthenium(III) analogue of the Udenfriend-type system Ru(III)-EDTA-ascorbate-02, for the selective oxygen-atom transfer to saturated and unsaturated hydrocarbons. The kinetics of the oxidation of p-XC6H4CHPhOH(X =... 

H, Cl, Br, NO2, Me, MeO) by bromamine-B, catalysed in the presence of HCl in 30% aqueous methanol by RuCls have been smdied and a biphasic Hammett a-relationship derived. A kinetic study of the ruthenium(in)-catalysed oxidation of aliphatic primary amines by sodium A-bromo-j -toluenesulfonamide (bromamine-T, BAT) in hydrochloric acid medium has been undertaken and the mechanism of the reaction discussed. A concerted hydrogen-atom transfer one-electron transfer mechanism is proposed for the ruthenium(in)-catalysed oxidation of 2-methylpentane-2,4-diol by alkaline hexacyanoferrate(III). The kinetics of the oxidation of propane-... 

I, 3-diol under the same conditions have been studied. Ruthenium(in) catalyses the oxidation of primary alcohols by bromamine-B. A Taft LFE reaction constant of p = —0.77 indicates the development of positive charge in the transition state. ... 

A primary kinetic isotope effect (kn/ko = 6.03 at 298 K) was observed for the oxidation of formic and oxalic acids by benzyltrimethylammonium tribromide (BTMAB) to carbon dioxide. The kinetics of oxidation of pyridoxine to pyridoxal by broma-mine-T and bromamine-B ° and caffeine by bromamine-B have been investigated. 

Catalysis of the oxidation of allyl and crotyl alcohols with chloramine-T, 375 chloramine-B, bromamine-T, and bromamine-B Catalysis of the chloramine-T oxidation of glycolic and lactic acids 376... 

The Ru(III)-catalysed oxidation of o-, m-, and p- hydroxybenzoic acids156-158 with bromamine-B (BAB) in acidic solution showed a first-order dependence on the reductant, BAB, and Ru(III). An inverse first-order dependence with respect to acidity has been observed. Mechanistic aspects have been discussed. 

MECHANISTIC INVESTIGATIONS OF OXIDATION OF PURINE AND PYRIMIDINE BASE COMPONENTS OF NUCLEIC ACIDS BY BROMAMINE-B IN AQUEOUS ALKALINE MEDIUM A KINETIC APPROACH... 

Mechanism of oxidation of purine bases (adenine and guanine) and pyrimidine bases (uracil, thymine and cytosine) in presence of NaOH by bromamine-B(BAB) has been investigated. The reactions follow identical kinetics for all the bases, being first order dependence on [BAB]o and fractional order each in [substrate]o and [NaOH]. Addition of the reaction product retards the rate and the dielectric effect is positive. Variation of ionic strength and addition of halide ions had no effect on the rate. Proton inventory studies were made in H2O-D2O mixtures for adenine and cytosine. Oxidation products were identified and activation parameters were evaluated. An isokinetic relationship is observed with p = 336 K indicated that enthalpy factors control the rate. The rate of oxidation of purines is in the order guanine > adenine while in case of pyrimidines the order is thymine > uracil > cytosine. A suitable mechanism is proposed and discussed. 

The possible oxidizing species in alkaline BAB solutions are PhS02NBr PhS02NHBr, HOBr and OBrHardy and Johnston s calculations[7] on alkaline bromamine-B solutions indicated that there could be considerable concentration of PhS02NHBr even in alkaline medium. Further as the concentration of alkali increases, there is also increase in the concentration of hypobromite ion. Hence, in the present investigations, a fractional order dependence on [substrate] and [OH and tbe observed retardation of rate by the reaction product (PhS02NH2) can be explained by tbe two pathway mechanism shown in schemes 1 and 2 ... 

KINETICS AND MECHANISM OF RUTHENIUM(HI) AND OSMIUM(VIII) CATALYZED OXIDATION OF DOPAMINE WITH BROMAMINE-B IN ACID AND ALKALINE MEDIA... 

The uncatalysed and Ru(ni) catalysed oxidations of niacin by bromamine-B in HCl has an inverse fractional order in HCl. The catalysed reaction is fractional order in Ru(III). The similarly catalysed bromamine-T (BAT) oxidation of trans-4-(aminomethyl) cyclohexanecarboxylic acid (Tx) in HCl to 4-formylcyclohexane-l-carboxylic acid is fractional orders in Tx, H+ ion and para-toluenesulfonamide (PTS). 

The oxidation of aspirin by A-sodio-A-bromobenzenesulfonamide (bromamine-B, BAB) in aqueous HCIO4 is first order in BAB, fractional order in aspirin and inverse fractional order in H+. The reaction proceeds via decarboxylation, bromination, and AcOH loss, affording the product 2,4,6-Br3CeH20H. The oxidation of D-cycloserine (CS) by BAB in HCl is first order in BAB and fractional order each in CS and H+. The proposed mechanism assumes simultaneous catalysis by H+ and Cl ions and is consistent with the observed kinetic results. The oxidation of diethylamine by BAB catalysed by ruthenium(III) is first order in oxidant, catalyst and substrate, but inverse fractional order in H+. A mechanism in which the metal coordinates the nitrogen atom of the amine before a slow electrophilic attack on the nitrogen by BAB, elimination of HBr, attack by water, and disproportionation affords acetaldehyde and ethylamine, which undergoes a similar oxidation. " ... 

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