Trimethylamine, N-oxidation

An analogous reaction occurs with dibenzoylacetylene, whereas the reaction fails with dimethyl acetylenedicarboxylate, benzoyl chloride and tosyl chloride. Decomplexation of compound 29 to 3-(cyclohepta-2,4,6-trienyl)-3//-azepine (73%) has been achieved with trimethylamine N-oxide. 

Another reagent that convert benzylic halides to aldehydes is pyridine followed by /7-nitrosodimethylaniline and then water, called the Krohnke reaction. Primary halides and tosylates have been oxidized to aldehydes by trimethylamine N-oxide, and by pyridine N-oxide with microwave irradiation. ... 

A combination of a metathesis and a Pauson-Khand reaction, which leads to tricyclic compounds starting from diene-ynes, has been described by Perez-Castells and colleagues [262]. Treatment of the Co-complex 6/3-86, obtained from the corresponding alkyne in 75 % yield, with 5 mol% of the Ru-catalyst 6/3-13 for 18 h, followed by addition of an N-oxide as trimethylamine-N-oxide (TMANO) or NMO as copromoters, gave 6/3-87 in 81% yield. 

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. 

Dimethyl 7-10-tetrahaptotricyclo[4.2.2.02 5]deca-3,7,9-triene-7,8-dicarboxy-late tricarbonyliron reacted readily with several 1,3-dipoles nitrile oxides, at the cyclobutene double bond, to give adducts from which the tricarbonyliron group could be easily removed by oxidative decomplexation with trimethylamine N-oxide (237). 

The phosphite formed was efficiently oxidized by MPBA (step b). Use of trimethylamine N-oxide as an oxidant was investigated in the hope that this reagent would oxidize the cyclic phosphite and that trimethylamine formed would be employed in the ring opening reaction (step c) to produce the phosphorylcholine in a one-flask procedure. In this case to avoid the residual oxidant in the product less than one equivalent of the oxidant was used and it was necessary to add an additional amount of trimethylamine to form the desired 2-(methacryloxy)ethylphosphorocholine in good yield. 

The total synthesis of carbazomycin D (263) was completed using the quinone imine cyclization route as described for the total synthesis of carbazomycin A (261) (see Scheme 5.86). Electrophilic substitution of the arylamine 780a by reaction with the complex salt 779 provided the iron complex 800. Using different grades of manganese dioxide, the oxidative cyclization of complex 800 was achieved in a two-step sequence to afford the tricarbonyliron complexes 801 (38%) and 802 (4%). By a subsequent proton-catalyzed isomerization, the 8-methoxy isomer 802 could be quantitatively transformed to the 6-methoxy isomer 801 due to the regio-directing effect of the 2-methoxy substituent of the intermediate cyclohexadienyl cation. Demetalation of complex 801 with trimethylamine N-oxide, followed by O-methylation of the intermediate 3-hydroxycarbazole derivative, provided carbazomycin D (263) (five steps and 23% overall yield based on 779) (611) (Scheme 5.91). 

If photochemical apparatus is not available, the cycloisomerization reaction can be conducted using trimethylamine N-oxide to promote oxidative decarbonylation of molybdenum hexacarbonyl in a mixture of EtjN and EtgO, followed by addition of 1-phenyl-3-butyn-1-ol (1). In the submitters hands, this procedure required somewhat higher loading of molybdenum hexacarbonyl, and purification of the 2-phenyl-2,3-dihydrofuran (2) product required silica gel chromatography. 

An efficient and selective Cu-assisted ortho-hydroxylation procedure for the conversion of benzoate to salicylate has been described, involving trimethylamine N-oxide (TMAO) as the oxidant [191,192]. The reaction was assumed to proceed via oxidation of a Cu carboxylate complex by TMAO to produce the active species (postulated to be a Cu hydroxo complex, but with only circumstantial evidence), followed by oxygen transfer to the benzoate group (Scheme 14). Using a set of different amide derivatives of benzoic acid, Comba and co-workers gained additional mechanistic hints in support of a reactive Cu-oxo or Cu-hydroxo intermediate that is stabilized by a five-membered chelate [193]. A pre-equilibrium involving Cu the ligand, and TMAO was proposed, but details of the reaction are far from clear. 

Figure 13. Separation of methylamines and methylamine-N-oxides from standard solutions. Analytes 1-sodium, 2-ammonium, 3-methylamine (195 pg/L), 4-dimethylamine (390 pg/L), 5-trimethylamine-N-oxide (465 pg/L), and 6-tri-methylamine (615 pg/L) [27],...

Figure 14. Chromatogram of smog chamber filter analysis from reaction of trimethylamine with ozone. Analytes 1-sodium, 2-ammonium, 3-potassium, 4-dimethylamine (1.72 pg/m ), 5-trimethylamine-N-oxide (0.25 pg/m ), 6-magnesium, and 7- trimethylamine (0.57 pg/m ). The inset is a magnification of the trimethylamine-N-oxide peak (5) from...

Higgins T, Chaykin S, Hammond KB, Humbert JR (1972) Trimethylamine-N-oxide synthesis a human variant. Biochem Med 6 392-3963... 

TorR -I- ATP <103> (<103>, TorS is a sensor that contains three phosphorylation sites and transphosphorylates TorR via a four-step phosphorelay, His443 to Asp723 to His850 to Asp(TorR). TorS can dephosphorylate phospho-TorR when trimethylamine N-oxide is removed. Dephosphorylation probably occurs by a reverse phosphorelay, Asp(TorR) to His850 to Asp723 [167]) (Reversibility <103> [167]) [167]... 

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)... 

Dihydroxylation of hindered double bonds. The a-pinene derivative 1 (Nopol) is hydroxylated in low yield by osmium tctroxide and f-butyl hydroperoxide. Hydroxylation is effecled in 62% yield by use of 0s04 in combination with trimethylamine N-oxide as oxidant and pyridine as base. This method is generally suitable for hindered alkenes (yields 78-93%). 

DIHYDROXYLATION Osmium tetroxide-Dihydroquinine acetate. Osmium tetrox-ide-Diphenyl selenoxide. Osmium tetroxide-Trimethylamine N-oxide-Pyiidine. Thallium(l) acetate-iodine. Triphenylmethylphosphonium permanganate. 

Catalysis of the trimethylamine N-oxide cis hydoxylation of cyclohexene 390 and a-pinene... 

A number of other reductases and dehydrogenases, including dissimilatory nitrate reductases of E. coli and of denitrifying bacteria (Chapter 18), belong to the DMSO reductase family. Other members are reductases for biotin S-oxide,649 trimethylamine N-oxide, and polysulfides as well as formate dehydrogenases (Eq. 16-63), formylmethanofuran dehydrogenase (Fig. 15-22,... 

In contrast, 1-methoxy- (or ethoxy-) carbonyl-l//-azepine-tricarbonyliron complex with the tetrazine diester undergoes unprecedented [2+4]7t cycloaddition at the C-2—C-3 azepine double bond to give, after loss of nitrogen and decomplexation and dehydrogenation using o-chloranil or trimethylamine N-oxide, the isomeric pyridazino[4,5-6]azepine system (82JOC110). Similar adducts are also obtained with tetrachlorothiophene 1,1-dioxide. 

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