Trimethylamine V-oxide

Reaction of [Pt3(/u-S02)3 P(Cy)3 3] with 2,6-xylyl isocyanide results in displacement of one or at most two of the S02 ligands by the isocyanide.21 Similarly, carbon monoxide usually only partially displaces the S02, but the addition of trimethylamine /V-oxide (Me3NO) facilitates the substitution leading to formation of [PtsQx-COjsfPlCyjs js].22 Me3NO also facilitates substitution of one S02 ligand by halides and azide.2... 

Rh6(CO)16 (107 mg, 0.1 mmol) is dissolved completely in a mixture of tri-chloromethane (150 mL) and acetonitrile (10 mL). A solution of trimethylamine /V-oxide (Me3N0-2H20) (12 mg, 0.11 mmol) in MeOH/CHCl3 (0.5/5.0 mL) is added dropwise under vigorous stirring to the cluster solution. The reaction mixture is allowed to stand for an additional 15 min. The product is isolated by the procedure described above. Yield of 70-75 mg of Rh6(CO)15NCMe 64-70%. 

Urine Tubulointerstitial lesions Glomerulonephritis 77 1H NMR Citrate, hippurate, glycine, creatinine, lactate, acetate, and trimethylamine-/V-oxide (52)... 

Osmylation of diastereomerically pure P-hydroxy sulfoximines, derived from 2a and cyclic enones, with a catalytic amount of osmium tetroxide (5 mol%) and trimethylamine V-oxide (1.5 equiv) gives diastereomerically pure triols which on thermolysis yield 2,3-dihydroxy cyclic ketones in high enantiomeric purity ( 100% ee). Osmylation occurs syn to the sulfoximine group.74... 

Analytical characterization Mass spectrometry2,4 is suitable for detecting triethylcyclotriboroxane (base peak m/z = 139) in tetraethyldiboroxane (base peak m/z = 125). 0.5% Triethylcyclotriboroxane (511b = 33 ppm) or triethylborane (fi j j = 86 ppm) in tetraethyldiboroxane (5 2 2 B = 53.3 ppm) can be identified by nB-NMR spectroscopy.5 Triethylcyclotriboroxane or triethylborane amounts can be determined quantitatively by finding the Bc-values using the trimethyl-amine /V-oxide method6 in conjunction with the combined pyridine /V-oxide/ trimethylamine, /V-oxide method and the total boron content. 

The dihydrocarbazolone iron complex (49 mg, 0.119 mmol) is dissolved in acetone (2 mL), trimethylamine /V-oxide dihydrate (74 mg, 0.666 mmol) is added, and the reaction mixture is stirred for 4 h at room temperature. The heterogeneous mixture is filtered... 

Baraquet, C., Theraulaz, L., Guiral, M., Lafitte, D., Mejean, V., and Jourlin-Castelli, C. (2006) TorT, a member of a new periplasmic binding protein family, triggers induction of the Tor respiratory system upon trimethylamine N-oxide electron-acceptor binding in Escherichia coli.J. Biol. Chem. 281, 38189-38199. 

Jourlin, C. Bengrine, A. Chippaux, M. Mejean, V. An unorthodox sensor protein (TorS) mediates the induction of the tor structural genes in response to trimethylamine N-oxide in Escherichia coli. Mol. Microbiol., 20, 1297-1306 (1996)... 

Simon, C. Mejean, V. Jourlin, C. Chippaux, M. Pascal, M.C. The torR gene of Escherichia coh encodes a response regulator protein involved in the expression of the trimethylamine N-oxide reductase genes. J. BacterioL, 176, 5601-5606 (1994)... 

Czjzek, M., Dos Santos, J.-P, Pommier, J., Giordano, G., MEJean, V., and Haser, R., 1998, Crystal structure of oxidized trimethylamine-N-oxide reductase from Shewanella massilia at 2.5 resolution, J. Mol. Biol. 284 43511447. 

The first oxoaUcyl of chromium(V), ( -C5Me5)CrO(Me)2, was prepared via oxygen transfer from trimethylamine N-oxide to the Cr precursor ( -C5Me5)Cr(py)Me2. Its effective magnetic moment at 285 K, 1.76 J,b, is consistent with the presence of pentavalent chromium. At ambient temperature and pressure, this complex does not function as an ethylene polymerization catalyst however, it does react with the starting material to give the Cr dimer [( l -C5Me5)Cr(Me)2]2(Ai2-0). Another chromium(V) alkyl, namely, dinuclear [Cp Cr(0)Me]2(/tr-0), was produced by the reaction of [Cp Cr(/u.-Me)]2 with O2. 

For the oxidation of alkenes, osmium tetroxide is used either stoichiometrically, when the alkene is precious or only small scale operation is required, or catalytically with a range of secondary oxidants which include metal chlorates, hydrogen peroxide, f-butyl hydroperoxide and N-methylmorpholine A -oxide. The osmium tetroxide//V-methylmorpholine A -oxide combination is probably the most general and effective procedure which is currently available for the syn hydroxylation of alkenes, although tetrasubstituted alkenes may be resistant to oxidation. For hindered alkenes, use of the related oxidant trimethylamine A -oxide in the presence of pyridine appears advantageous. When r-butyl hydroperoxide is used as a cooxidant, problems of overoxidation are avoided which occasionally occur with the catalytic procedures using metal chlorates or hydrogen peroxide. Further, in the presence of tetraethylam-monium hydroxide hydroxylation of tetrasubstituted alkenes is possible, but the alkaline conditions clearly limit the application. 

Nicotine is an example of a compound that undergoes FM03-catalyzed N-oxidation, as shown in Scheme 11.27. About 4% of nicotine is stereoselec-tively metabolized to trans-(S)-(—)-nicotine N-V oxide in humans by FM03, whereas 30% of an administered dose appears as cotinine, a CYP2A6 product (34, 35). Other examples of FMO N-oxidation include trimethylamine, amphetamine, and the phenothi-azines (33). As described previously, FM03 catalyzes S-oxidation of substrates such as cimetidine, shown in Scheme 11.28, and chlorpromazine, also a CYP3A substrate (Scheme 11.22). 

Bennion BJ, DeMarco ML, Daggett V (2004) Preventing misfolding of the prion protein by trimethylamine N-oxide. Biochemistry 43 12955... 

Granata V, Palladino P, Tizzano B, Negro A, Berisio R, Zagari A (2006) The effect of the osmolyte trimethylamine N-oxide on the stability of the prion protein at low pH. Biopolymers 82 234... 

Bennion BJ, Daggett V (2004) Counteraction of urea-induced protein denaturation by trimethylamine N-oxide a chemical chaperone at atomic resolution. Proc Natl Acad Sci USA 101 6433... 

Hydroboration of 1-methylcyclopropene with diborane in pentane gave the (2-methylcyclo-propyl)borane 11 (>80%), together with traces of the regioisomer 12, but addition of tetraethyldiborane resulted in essentially complete addition of boron to the less-substituted terminus of the 7t-bond.106 Oxidation of 11 with trimethylamine A-oxide provides a convenient access to tra/i.v-2-methylcyclopropanol. The same product can be obtained by hydroboration of 3-methylcyclopropene with tetramethyldiborane.107... 

Almost all of the Mo and W enzymes show paramagnetic pentavalent forms that can be studied by methods such as EPR spectroscopy, and EPR in particular has been extensively used to study the enzymes. Beeause the pentavalent form is typieally only a fraction of the total metal present, few parallel studies using XAS have been reported. Rhodobacter DMSO reduetase, however, is one notable exeeption. In this case there are two different forms that show essentially 100% of Mo as the Mo(v) form. The first is an inhibited species, which forms with vicinal diols such as glycerol, and is a stable Mo(v) entity that is resistant to both oxidation and reduction. This species was studied in the first XAS report on DMSO reductase, and was fou nd to be a six-coordinate complex with four equivalent sulfurs and two Mo-0 bonds, probably from the vicinal diol coordinated to Mo(v). The stability of this spe-eies means that it has little catalytic relevance, but the second quantitatively Mo(v) DMSO reductase species is formed by reduction with the alternative substrate trimethylamine Af-oxide (TMAO). This substrate forms the most... 

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