Amine oxides trimethylamine oxide

Oehlenschlalager, J. 1997. Suitability of ammonia-N, dimethylamine-N, trimethyl-amine-N, trimethylamine oxide-N and total volatile basic nitrogen as freshness indicators in seafood. In Methods to Determine the Freshness of Fish in Research and Industry. Nantes Conference, November 12-14. 

Notable examples of general synthetic procedures in Volume 47 include the synthesis of aromatic aldehydes (from dichloro-methyl methyl ether), aliphatic aldehydes (from alkyl halides and trimethylamine oxide and by oxidation of alcohols using dimethyl sulfoxide, dicyclohexylcarbodiimide, and pyridinum trifluoro-acetate the latter method is particularly useful since the conditions are so mild), carbethoxycycloalkanones (from sodium hydride, diethyl carbonate, and the cycloalkanone), m-dialkylbenzenes (from the />-isomer by isomerization with hydrogen fluoride and boron trifluoride), and the deamination of amines (by conversion to the nitrosoamide and thermolysis to the ester). Other general methods are represented by the synthesis of 1 J-difluoroolefins (from sodium chlorodifluoroacetate, triphenyl phosphine, and an aldehyde or ketone), the nitration of aromatic rings (with ni-tronium tetrafluoroborate), the reductive methylation of aromatic nitro compounds (with formaldehyde and hydrogen), the synthesis of dialkyl ketones (from carboxylic acids and iron powder), and the preparation of 1-substituted cyclopropanols (from the condensation of a 1,3-dichloro-2-propanol derivative and ethyl-... 

A comparative study of the analysis of aliphatic amines by GC-FID, GC-TSD and HPLC with refractive index detector (RID), using isopropylamine as internal standard, gave good results in all cases. Determination of trimethylamine oxide by HPLC with a pulsed amperometric detector was problematic136. 

Also, attempts to convert phosphine to PH3O using amine oxides, such as trimethylamine oxide and pyridine oxide, did not proceed to the result formulated in Eq. (19)... 

N-oxidation. The oxidation of nitrogen in tertiary amines, amides, imines, hydrazines, and heterocyclic rings may be catalyzed by microsomal enzymes or by other enzymes (see below). Thus the oxidation of trimethylamine to anN-oxide (Fig. 4.19) is catalyzed by the microsomal FAD-containing mono oxygenase. The N-oxide so formed may undergo enzyme-catalyzed decomposition to a secondary amine and aldehyde. This N to C transoxygenation is mediated by cytochromes P-450. The N-oxidation of 3-methylpyridine, however, is catalyzed by cytochromes P-450. This reaction may be involved in the toxicity of the analogue,... 

Deprotonation of t-amine oxides LDA (excess) converts trimethylamine oxide into a reactive ylide (a) that dimerizes to the dimethylpiperazine (2). If a is generated in the presence of an alkene, pyrrolidines (3) are formed via a 1,3-dipolar cycloaddition. The ylide reacts with cyclic alkenes to form bicyclic pyrrolidines in 40-90% yield.2... 

Trimethylamine Oxide Spectra. Assignment of the major IR bands associated with the amine oxide headgroup were made based on aqueous solution spectra of trimethylamine oxide (Figure 1), tire spectrum of solid C12AO (Figure 2), and... 

Although a variety of amines, particularly trimethylamine and n-butylamine have widely been used as poisons in catalytic reactions and for surface acidity determinations (20), comparably few spectroscopic data of adsorbed amines are available. As with ammonia, coordinatively adsorbed amines held by co-ordinatively unsaturated cations have preferentially been found on pure oxides (176, 193-196), whereas the protonated species were additionally observed on the surfaces of silica-aluminas and zeolites (196-199). However, protonated species have also been detected on n-butylamine adsorption on alumina (196) and trimethylamine adsorption on anatase (176) due to the high basicity of these aliphatic amines. In addition, there is some evidence for dissociative adsorption of n-butylamine (196) and trimethylamine (221) on silica-alumina. Some amines undergo chemical transformations at higher temperatures (195, 200) and aromatic amines, such as diphenylamine, have been shown to produce cation radicals on silica-alumina (201, 201a). 

A very specific yet interesting epoxidation method for bicyclic a,(3-unsaturated sulfones has been reported <07SL1948>. Reaction of bicyclic sulfone 10 with A-methylmorpholine N-oxide (NMO) provides the epoxide product in generally good yields. Other amine oxides such as trimethylamine A-oxide work in this reaction, however non-strained sulfones do not react even with heating. 

In the oxide of trimethylamine, (GH3)3NO, the electron diffraction data of Lister and Sutton show that the NO bond distance is 1 36 A which is approximately the value for a single bond. If the nitrogen were penta valent, the bond would be double and the distance less and evidently, in the amine oxides, structures of the type (GH3)3N—O, make a large contribution. In nitrosyl chloride and nitrosyl bromide the NO bond length is decreased, from i ii to 1 14 A, which suggests that the bond is a hybrid of the structures... 

A mixture of 100 ml. of aqueous 33% trimethylamine solution and 600 ml. of 3% hydrogen peroxide is allowed to stand for 24 hours. If the odor of the amine is still apparent, another 100-200 ml. of hydrogen peroxide is added. After the amine odor has disappeared, the mixture is evaporated under vacuum and the residue is recrystallized from ethanol-ether mixture. The yield of trimethylamine oxide di-hydrate, m.p. 96°, is aroimd 95%. 

For dehydration 10 g. of the amine oxide dihydrate is placed in a 150-ml. flask which has a long, wide neck. Some boiling chips are added, and the compound is heated in an oil bath under a water pump vacuum of 10-12 mm. A calcium chloride tube is placed between the water pump and the flask. At an oil bath temperature of 120°, the amine oxide dihydrate melts and begins to bubble. The temperature is raised very slowly. After most of the water is off, the temperature of the bath is maintained at 140-150° for 10 minutes. A new calcium chloride tube is placed in the apparatus, and it is again heated under vacuum. At 180° sublimation starts, and anhydrous amine oxide collects in the neck of the flask. The mixture is held at a bath temperature of 190-200° for 1.5 hours to complete the sublimation. The yield of anhydrous trimethylamine oxide is around 95%. The material is extremely hygroscopic. A sample in a capillary tube melts at 208° after subliming around 180°. 

An easy route to amine oxides is the oxidation of tertiary amines with /n-chloroperoxybenzoic acid in chloroform solution at 0-5 °C for 3 h. Trimethylamine oxide, tribenzylamine oxide, and dimethylaniline oxide are obtained in 96, 96, and 94% yields, respectively [320],... 

To 2 ml of trimethylamine (33 per cent solution) add 13 ml of 3 per cent hydrogen peroxide. Cork, and let stand until the next laboratory period. Note whether any odor of amine remains. Evaporate to dryness on a water bath, and add 2 ml of alcohol. The crystals which separate out are the hydrate of trimethylamine oxide, (CH3)3N0-2 H O. 

A final difference between amine oxides and phosphine oxides lies in the polarity of the molecules. The dipole moment of trimethylamine oxide is 16.7 X 10 C m (5.02 D) compared with 14.6 x 10 C m (4.37 D) for triethylphosphine oxide. A consequence of this polarity is the tendency of the amine oxides to form hydrates, R3NO H2O, and their greater basicity relative to the phosphine oxides. 

Oxidations. This reagent combination (the amine oxide being IV-methylmorpholine N-oxide) has been used to oxidize organoboranes to fiimish carbonyl compounds, and in the presence of AgOAc and 4A molecular sieves it oxidizes secondary nitroalkanes to ketones. A modified reagent consists of a polymer-linked trimethylammonium perruthenate and trimethylamine oxide. ... 

Trimethylamine and other amines have often been variously associated with the aromas of fish (2, 19, 41). Much of the trimethylamine found in fresh fish arises from the microbial reduction of trimethylamine oxide (42-44) which is found abundantly in only marine fish (45-47). On the other hand, dimethylamine is an abundant product of an endogenous enzymic action on trimethylamine oxide in marine fish muscle, and it is readily produced even under high-sub-freezing conditions in marine fish (48). Both trimethylamine and dimethylamine... 

The reaction of trifluoroacetic anhydride on the A(-oxides of 3)5-dimethytamino-steroids (51) (e.g., iV-methyl-5a-dihydroparavallarine) leads to the immonium salts (52) and (53), which can be hydrolysed to the 3-keto- or the 3-methylamino-steroid, respectively. " This reaction is generally applicable to other amines trimethylamine oxide is converted into iViV-dimethylformaldimmonium tri-fluoroacetate (54), which is an excellent Mannich reagent. ... 

Following this initial preparation of a stable material having an ylid structure, a variety of phosphorus, arsenic, and sulfur ylids have been prepared and characterized and their chemistry has been thoroughly reviewed 78>. The chemistry of trimethylamine imine 2> and trimethyl-amine oxide, compounds which are isoelectronic with the ylid, have been reviewed 30,78) and will not be described here. 

This type of reaction is termed an a -(3 elimination and it is isoelec-tronically similar to the pyrolysis of amine oxides 30>. However, the occurrence of an a -(3 elimination was subsequently disproven in this particular reaction because the trimethylamine which forms in the decomposition of s-2-phenyl-2-deuterocyclohexyltrimethylammonium hydroxide contains no deuterium T>. Therefore, a cis E-2 mechanism was proposed to account for the experimental observations 36>. 

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