Trimethylamine oxide, reaction with

Trimethylamine, CjH N, (CH3J3N. Colourless liquid with a strong fishy odour, miscible with water, m.p. — I24 C, b.p. 3-5°C. It occurs naturally in plants, herring brine, bone oil and urine. It reacts with hydrogen peroxide to give trimethylamine oxide and with ethylene oxide to give choline its commercial importance stems chiefly from this latter reaction. 

The first class of reactions, direct transfer of an oxygen atom from the oxidant to carbon monoxide, has not been commonly observed as a reaction catalyzed by metal complexes in solution. One example, derived from a preparative procedure developed to substitute carbonyls with other ligands (90), is the reaction of trimethylamine oxide, Me3NO, with carbonyl clusters such as Os3(CO)12 in the presence of excess CO. The net reaction is shown as (27). 

Purine, 6-bromo-9-/3-D-(2,3,5-tri-0-acetyl)ribofuranosyl-synthesis, 5, 598 Purine, 6-carboxy-reactions, 5, 549 Purine, 8-carboxy-reactions, 5, 549 Purine, 2-chloro-reactions, 5, 561 synthesis, 5, 597 Purine, 6-chloro-alkylation, 5, 529 glycosylation, 5, 529 oxidation, 5, 539 3-oxides reactions, 5, 554 synthesis, 5, 595 reactions, 5, 561, 595 with ammonia, 5, 562 with fluorides, 5, 563 with trimethylamine, 5, 562 9- -D-ribofuranoside synthesis, 5, 560 synthesis, 5, 597, 598 Purine, 8-chloro-amination, 5, 542 Purine, 6-chloro-8-ethoxy-synthesis, 5, 591 Purine, 6-chloro-9-ethyl-dipole moment, 5, 522 Purine, 6-chloro-2-fluoro-riboside... 

These routes are dimerization to furoxans 2 proceeding at ambient and lower temperatures for all nitrile oxides excluding those, in which the fulmido group is sterically shielded, isomerization to isocyanates 3, which proceeds at elevated temperature, is practically the only reaction of sterically stabilized nitrile oxides. Dimerizations to 1,2,4-oxadiazole 4-oxides 4 in the presence of trimethylamine (4) or BF3 (1 BF3 = 2 1) (24) and to 1,4,2,5-dioxadiazines 5 in excess BF3 (1, 24) or in the presence of pyridine (4) are of lesser importance. Strong reactivity of nitrile oxides is based mainly on their ability to add nucleophiles and particularly enter 1,3-dipolar cycloaddition reactions with various dipolarophiles (see Sections 1.3 and 1.4). 

Acetylcholine Acetylcholine, 2-acetoxy-A,A,A-trimethylethyl ammonium chloride (13.1.2), is easily synthesized in a number of different ways. For example, 2-chloroethanol is reacted with trimethylamine, and the resulting A,A,A-trimethylethyl-2-ethanolamine hydrochloride (13.1.1), also called choline, is acetylated by acetic acid anhydride or acetylchloride, giving acetylcholine (13.1.2). A second method consists of reacting trimethylamine with ethylene oxide, giving A,A,A-trimethylethyl-2-ethanolamine hydroxide (13.1.3), which upon reaction with hydrogen chloride changes into the hydrochloride (13.1.1), which is further acetylated in the manner described above. Finally, acetylcholine is also formed by reacting 2-chloroethanol acetate with trimethylamine [1-7]. 

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). 

The molybdenum-catalyzed cyclization procedure works well for a variety of homoprogargylic alcohols to afford the cycloisomeric 2,3-dihydrofuran compounds, as shown in Table I. The transformation was originally discovered with the reagent arising from reaction of molydbenum hexacarbonyl and trimethylamine oxide, but catalyst turnover and product isolation yields are significantly improved with the cunent procedure, which... 

Phosphine reacts neither in aqueous solution nor direct with trimethylamine oxide. Also no reaction occurs on treatment of phosphine with pyridine oxide... 

The 5,6-double bond in activated pyrimidines can participate in thermal [4-1-2] cyclization reactions as demonstrated by the 1,3-dipolar cycloaddition reactions of O-protected thymidine derivatives 483 with the nonstabilized azo-methine ylide 484, which is generated from trimethylamine AT-oxide by reaction with EDA <2002SC1977>. 

The preparation of complexes 1 or 2 involves the reaction of Os3(CO)12 in acetonitrile with trimethylamine oxide, which removes CO ligands as C02 the vacant site(s) on the cluster are then filled by acetonitrile rather than the resulting trimethylamine, which is a poorer coordinating ligand. Complexes 1 or 2 are easily isolated in high yields. Their syntheses are reported in detail here, together with the synthesis of a typical derivative Os COJufCsHsN). 

Material 1 was also treated with 3-bromopropyltrichlorosilane to yield a propyl tether with a bromo-head group (4). Substitution with either trimethylamine or triethylamine to form the corresponding quaternary ammonium species, followed by ion exchange with potassium perruthenate afforded the catalytic species (5) and (6) respectively. The black solid 5 was found to be an equally efficient catalyst for the oxidation reactions and 6 was found to be a more highly active recoverable and reusable... 

Reactions of trimethylamine A-oxide have been mentioned as synthetically useful and relevant to the reaction of trimethylamine A-oxide reductase [82], Sarkar and coworkers have also reported the reactions with C02, HS03 [189], and acetylenes [186]. Sarkar and Das reported [190] that WO(mnt)22 reacts with C02/HC03 to form HCOO and W02(mnt)22. This formal reduction of C02... 

The currently available methods for the synthesis of the title compounds are confined to the preparation of homo-1,1-dihalo-1-alkenes 180 while only a few reports are available for mixed 1,1-dihalo-1-alkenes of defined stereochemistry 18u. As the hy-droboration reaction proceeds in a stereospecific manner, the hydroboration-oxi-dation-bromination-debromoboration sequence of 1-chloro-l-alkynes produces selectively (Z)-l-bromo-l -chloro-l-alkenes (Eq. 116),82>. The oxidation with anhydrous trimethylamine oxide of the alkenylborane prior to the addition of bromine is necessary to avoid the competing transfer of one of 1,2-dimethylpropyl group from boron to the adjacent carbon atom. Similar reaction sequence provides 1,1-dibromo-l-alkenes (Eq. 117)182). 

The cobalt-silicon compounds described here undergo reactions with protonic molecules such as hydrogen chloride, Lewis bases such as trimethylamine, and oxidizing agents. 

Anhydrous trimethylamine N-oxide has been suggested as an alternative, neutral oxidant, although with dialkoxysilanes relatively high reaction temperatures are required. Alkyltrifluorosilanes, on the other hand, undergo cleavage with this oxidant at room temperature. ... 

Methyleneimmonium salts 31 are conveniently prepared from mcihylene-bis-amines, formaldehyde-N,0-acetals, or methylene halogenides. Electrochemical reactions on various alkylamines have also been used to generate methyleneimmonium salts, and trimethylamine N-oxide 34 (Fig. 20) is reported as a source of the corresponding methyleneimmonium salt by reaction with trifluoroacetic anhydride. ... 

Some examples of industrially important uses are the following reactions With alkyl halides or alcohols amines or imines can be manufactured. For example, inethanol forms mono- through trimethylamine dichloromethane yields ethylene imine in the presence of calcium oxide. Amines can also be produced by reacting ammonia with alkyl halides in multistage processes [1425]. 

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