Relative rates of reduction

Krapcho and Bothner-By made additional findings that are valuable ii understanding the Birch reduction. The relative rates of reduction o benzene by lithium, sodium and potassium (ethanol as proton donor) wer found to be approximately 180 1 0.5. In addition, they found that ben zene is reduced fourteen times more rapidly when methanol is the protoi donor than when /-butyl alcohol is used. Finally, the relative rates of reduc tion of various simple aromatic compounds by lithium were deteiTnined these data are given in Table 1-2. Taken together, the above data sho that the rate of a given Birch reduction is strikingly controlled by the meta... 

Relative Rates of Reduction of Substituted Benzenes Relative t<... 

The relative rate of reduction by lithium with respect to sodium was misquoted by me ii ref. 29 as 62.5 1. Eastham has criticized the accuracy of the original data and Krapchc and Bothner-By have agreed that their rate constants may have been in error. Thi figures cited above include lough corrections made in accord with Krapcho and Bothner-By estimates of the errors. 

The above syntheses of metal nanowires are based on the thermal hydrogen reduction. However, we found that the reproducible synthesis is difficult by this method, because the hydrogen reduction needs careful control of the reaction conditions. For the reproducible and selective synthesis of wires and particles, we need to clarify the factors controlling the sintering of metals. The key factors are the concentration of residual solvent and the relative rate of reduction and migration of metal ions. The details are shown in the next section. 

An alternative means to determine the relative rates of reduction of M and D, ie. K = kM/kD, is afforded by comparing the simultaneous (n-Bu)3SnH reductions of DCP and 2-chlorooctane (M ) to pentane and octane (O), respectively. 

The metabolism studies with cyanide present showed no dehydrogenation whatsoever of the substrate. It is thus considered likely that the resazurin and the resorufin interact with some metal bearing system, possibly the cytochromes participating in the hydrogen transfer. Although the resazurin (or resorufin) may interact in a system several steps removed from the dehydrogenation of the particular substrates, the relative rates of reduction of the indicator are still comparable with the relative oxidation rates of the substrates. 

An interesting study of the relative rates of reduction of N,N-bis(2-chloroethyl)-aminoazobenzene and various monosubstituted derivatives (3.27) was initiated because of the ability of such dyes to inhibit the growth of animal tumours [23], even though some... 

Ru complex Viologen Environment fcq(mol 1 dm3 s ) Relative rate of reduction... 

The problem of ordering platinum group metals for the relative rate of reduction of various functions in competition is, with few exceptions, unsolved. A generalized solution would do much to aid in the proper choice of metal for selective reduction of bifunctional compounds. 

Of special interest are the relative rates of reduction of various cyclic enones, such as carvone, acetylcyclohexene and pulegone (Scheme 60). While the enone system in carvone is frozen in its transoid... 

The diamond lattice model (Figure 7) was developed using six-membered ring ketone substrates. The determination of forbidden and undesirable positions was achieved by analysis of the relative rates of reduction of a series of cyclohexanones and decalones of known absolute configuration. The geometry indicated at the C-0 centre was considered to resemble the structure of the alcohol rather than that of the ketone in the transition state. It was assumed that all substrate molecules bound with oxygen in the... 

As in the Jones protocol the cubic section model of the substrate binding domain of HLADH were constructed using structures of alcohol products rather than ketone substrates. The alcohol products were originally chosen by the Jones group because the transition state the geometry for the reduction was considered to resemble that of the alcohol rather than that of the ketone. The relative rate of reduction of substrate vs cyclohexanone for each ketone was required to be known. Furthermore, configurations of alcohol products, enantiomeric excess values, yields and % conversion of substrate required for calculation of the priority number for each enantiomer of product should be measured under comparable conditions (i.e. pH, temperature, concentration of enzyme, coenzyme and substrate, etc.). According to Alderweireldt et al. (1988) HLADH models are valid only for reaction conditions used in the reactions from which the models are constructed. Furthermore, the model is oniy reliable if the reactions have been conducted under kinetic control. 

The priority number for an alcohol product was determined by the relative rate and the stereoselectivity of reduction. The priority number for each substrate surrogate was calculated from the rates of production of each enantiomeric alcohol product using the total relative rate of reduction vs cyclohexanol and the enantiomeric ratio (E) formula derived by Sih (Table 5). ... 

Relative rates of reductive elimination and / -hydrogen elimination. . 499... 

As discussed previously, the relative rates of reduction of several bismuth molybdate-based catalyst systems using propylene decrease in the order multicomponent system > Bi2Mo2O9(j6) Bi2Mo3O,2(a) > Bi3FeMo2Oj2... 

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