Reversible losses

Other mechanisms must also operate, however, to account tor the fact that 5-10% of the product is formed with retained configuration at the chiral center. Isotopic labeling studies have also demonstrated that the 3-bromo-2-butyl radical undergoes reversible loss of bromine atom to give 2-butene at a rate which is competitive with that of the bromination reaction ... 

Anesthetic, general. A compound that, when given systemically, causes a reversible loss of consciousness sufficient to allow surgical procedures. 

When heated to 100 CC/ D-idose undergoes a reversible loss of water and exists primarily as 1,6-anhydro-n-idopyranose. 

Special senses—visual disturbances, blurred or diminished vision, diplopia, swollen or irritated eyes, photophobia, reversible loss of color vision, tinnitus, taste change, and rhinitis... 

Burk and coworkers have used a variety of nitrilases for the DKR of cyanohydrins [48]. Nitrilases catalyze the hydrolytic conversion of cyanohydrins directly to the corresponding carboxylic acids. Racemization was performed under basic conditions (phosphate buffer, pH 8) through reversible loss of HCN. (R)-Mandelic acid was obtained in high yield (86% yield) and high enantioselectivity (98% ee) after 3 hours (Figure 4.23). 

The addition of HCN to aldehydes or ketones produces cyanohydrins (a-hydroxy nitriles). Cyanohydrins racemize under basic conditions through reversible loss of FiCN as illustrated in Figure 6.30. Enantiopure a-hydroxy acids can be obtained via the DKR of racemic cyanohydrins in the presence of an enantioselective nitriletransforming enzyme [86-88]. Many nitrile hydratases are metalloenzymes sensitive to cyanide and a nitrilase is usually used in this biotransformation. The DKR of mandelonitrile has been extended to an industrial process for the manufacture of (R)-mandelic acid [89]. 

One specific advantage of the frozen noble gas is that it does not absorb IR and thus it is possible, in principle, to examine the spectrum of any coordinated ligand within the matrix. In practice, it is more difficult because, although the intensity of v(N-N) and V(N-O) bands are comparable with V(C-O) bands, most of the vibrations of other ligands give rather weak IR bands. However, as an example, in recent important work, Perutz (8) has demonstrated that photolysis of CpRh(C2H ) in Ar matrices at 20K leads to reversible loss of C2H to form CpRh(C2H ) identified by IR... 

M.W. Pantoliano, P.J. McDonnell, and J.S. Valentine, Reversible loss of metal ions from the zinc binding site of copper-zinc superoxide dismutase. The low pH transition. J. Amer. Chem. Soc. 101, 6454— 6456 (1979). 

These observations illustrate that there are two transformations open to metallocarboxylic acid intermediates reversible loss of OH" accompanied by oxygen exchange, and metal-hydride formation with expulsion of C02. Our entry into this area of chemistry was in 1975 when extensive studies of oxygen lability in metal carbonyl cations were initiated (10). These... 

A hydrate is a compound that contains water, rather loosely bound. Usually mild heating of the compound can drive off this water of hydration. Addition of water to the anhydrous salt reforms the hydrate (reversible loss/gain of water)... 

Comprehensive discussions of fuel cells and Camot engines Nemst law analytical fuel cell modeling reversible losses and Nemst loss and irreversible losses, multistage oxidation, and equipartition of driving forces. Includes new developments and applications of fuel cells in trigeneration systems coal/biomass fuel cell systems indirect carbon fuel cells and direct carbon fuel cells. 

In surgical practice, the term general anesthesia (narcosis) presently refers to the condition of an organism with a reversible loss of consciousness at a controlled level of nervous system suppression. It includes the following components analgesia (absence of pain), amnesia (absence of memory), suppression of reflexes such as bradycardia, laryngospasm, and loss of skeletal muscle tonicity. 

Special senses - Blurred vision photophobia amblyopia swollen, dry, or irritated eyes conjunctivitis iritis reversible loss of color vision hearing disturbances or loss ear pain change in taste (metallic or bitter) diplopia tinnitus. 

The divalent metal squarate complexes, M(squarate)(H20)2, decompose in a vacuum in two stages. First there is a reversible loss of two water molecules, followed at higher temperatures by decomposition to the metal. The nature of the anhydrous complexes is not fully understood but the metal atoms appear to be four-coordinate.174... 

While complex nitrate esters, such as nitrocellulose and nitroglycerin, were the first to find application as explosives, understanding the mechanisms of nitrate ester decomposition was accomplished through the study of simpler compounds [11-16]. Ethanol nitrate was examhed by numerous researchers, and they conceded the first, and rate-determining, step was reversible loss of... 

Taking into account this lack of stereoselectivity and equilibration between allenic stereoisomers, Benn proposed a mechanism in which silver ion facilitates the acyloxy shift on formation of n complex (or a bridged ionic silver intermediate).52 The thus-formed acetoxyallenes would remain coordinated to silver, allowing the formation of an organosilver allyl cation. Free rotation at this stage would provide both acetoxy-allene isomers after reversible loss of silver (Scheme 3.32). 

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