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Trimethylamine N-oxide, also known by several other names and acronyms, is the organic compound with the formula (CH3)3NO. This colourless solid is usually encountered as the dihydrate. It is an oxidation product of trimethylamine and a common metabolite in animals. It is an osmolyte found in saltwater fish, sharks and rays, molluscs, and crustaceans. Along with free amino acids, it reduces the 3% salinity of seawater to about 1% of dissolved solids inside cells. TMAO decomposes to trimethylamine (TMA), which is the main odorant that is characteristic of degrading seafood.
Synthesis
Treatment of aqueous trimethylamine with hydrogen peroxide affords the dihydrate (Me = CH3):[1]
- H2O2 + Me3N ? H2O + Me3NO
Trimethylamine-N-oxide is biosynthesized from from trimethylamine, which is derived from choline.[2]
Trimethylaminuria
Trimethylaminuria is a defect in the production of the enzyme flavin containing monooxygenase 3 (FMO3),[3][4], causing incomplete breakdown of trimethylamine from choline-containing food into trimethylamine oxide. Trimethylamine then builds up and is released in the person's sweat, urine, and breath, giving off a strong fishy odor.
Laboratory applications
Trimethylamine oxide is used in protein folding experiments to counteract the unfolding effects of urea. [5]
In organometallic chemistry, Me3NO is employed as a decarbonylation agent according to the following stoichiometry:
- M(CO)n + Me3NO + L ? M(CO)n-1L + Me3N + CO2
This reaction is used to decomplex organic ligands from metals, e.g. from (diene)Fe(CO)3.[1]
It is used in certain oxidation reactions, e.g. the conversion of alkyl iodides to the aldehyde.[6]
References
- ^ a b A. J. Pearson "Trimethylamine N-Oxide" in Encyclopedia of Reagents for Organic Synthesis John Wiley & Sons, 2001: New York. doi:10.1002/047084289X.rt268
- ^ Baker, J.R.; Chaykin, S. (01 Apr 1962). "The biosynthesis of trimethylamine-N-oxide". J. Biol. Chem. 237 (4): 1309–13. PMID 13864146, http://www.jbc.org/cgi/content/citation/237/4/1309.
- ^ Treacy, E.P.; et al. (1998). "Mutations of the flavin-containing monooxygenase gene (FMO3) cause trimethylaminuria, a defect in detoxication". Human Molecular Genetics 7 (5): 839–45. doi:10.1093/hmg/7.5.839. PMID 9536088.
- ^ Zschocke J, Kohlmueller D, Quak E, Meissner T, Hoffmann GF, Mayatepek E (1999). "Mild trimethylaminuria caused by common variants in FMO3 gene". Lancet 354 (9181): 834–5. PMID 10485731.
- ^ Zou, Q., et al (2002). "The Molecular Mechanism of Stabilization of Proteins by TMAO and Its Ability to Counteract the Effects of Urea". J. Am. Chem. Soc. 124 (7): 1192. doi:10.1021/ja004206b.
- ^ Volker Franzen (1973). "Octanal". Org. Synth.; Coll. Vol. 5: 872.
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