Trimethylamine oxide reagent

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... 

Other reagents that convert benzylic halides to aldehydes are 2-nitropropane-NaOEt in EtOH,336 mercury(I) nitrate followed by ethanolic alkali,337 and pyridine followed by p-nitrosodimethylaniline and then water. The last procedure is called the Krohnke reaction. Primary halides in general have been oxidized to aldehydes by trimethylamine oxide,338 by... 

Monohydroboration of bis(trimethylsilyl)acetylene and oxidation of the resultant trivinylborane with anhydrous trimethylamine oxide followed by hydrolytic workup affords [(trimethylsilyl)acetyl]trimethylsilane, which contains both a- and 3-ketosi-lane structural features. This reagent is a versatile synthon for stereoselective syntheses of functionalized trisubstituted olefins. 

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. ... 

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. ... 

Dimethyl sulfoxide-Sulfur trioxide [1, 309, before references]. The combination of DMSO and sulfur trioxide, in the form of the pyridine complex, in the presence of trimethylamine oxidizes primary and secondary alcohols in good yield to aldehydes and ketones, respectively.55 The reaction usually is complete within minutes and the products are isolated by acidification and precipitation with water. The reagent also oxidizes allylic alcohols to the corresponding a,fi-unsaturated carbonyl compounds. One advantage over the DMSO-DCC method is that the elaborate purification required when dicyclohexylurea is a product can be dispensed with. Testosterone, with a 17/3-hydroxyl group, was oxidized toA -androstene-3,17-dione very rapidly the 17-epimer required a period of 35 min. 

Liberation of organic ligands from iron carbonyl complexes. Oxidizing reagents (CAN, ferric chloride, lead tetraacetate) have been used to free an organic ligand from complexes with Fe(CO)3 and Fe(CO)4. Israeli chemists report that amine oxides, particularly trimethylamine oxide, are useful for this purpose. Relatively low temperatures (25-81°) can be used and the oxide is transformed into trimethylamine (volatile). Carbon dioxide is formed. 

The solid white decaethyl-2,6,8,10-tetracarbadecaborane(10) (C) can be exposed to air and moisture for only a short time without changing its appearance and composition at room temperature. Compound C is stable to iodine at room temperature. The solution of C in THF is attacked by metallic potassium to form a pale-yellow-colored mixture. Compound C reacts analogously to A with anhydrous (CH3)3NO above 75°. In refluxing toluene 1 mol of C liberates more than 16 mol of trimethylamine from the N-oxide reagent. 

Another nucleophilic reagent that is effective with tri- and tetrasubstituted per-fluoroalkenes is trimethylamine oxide. Attack by the oxygen atom is followed by elimination of trimethylamine. The amine oxide can be used catalytically as well as stoichiometrically, as w-chloroperbenzoic acid (MCPBA) or urea/hydrogen peroxide... 

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. 

Trimethylamine N-oxide, 325 Vinyltrimethylsilane, 343 Other reactions (Phenylsulfonyl)allene, 247 Cyclodehydration Diethoxytriphenylphosphorane, 109 Hexamethylphosphoric triamide, 142 Cycloprop anation Simmons-Smith reaction Diiodomethane-Diethylzinc, 276 Simmons-Smith reagent, 275 by other reagents which add CH2 to a carbon-carbon multiple bond Dibromomethane-Zinc-Copper(I) chloride, 93... 

The oxidation step is usually carried out in situ and is illustrated by the conversion of hex-l-ene into hexan-l-ol (Expt 5.44) trimethylamine ZV-oxide has been suggested as a safer alternative oxidising reagent.65 The g.l.c. analysis of the... 

Materials. Trimethylamine N-oxide dihydrate (98%) from Aldrich and N-dimethyldodecylamine N-oxide (97%) from Fluka Chemie were used as received. N-dimethylhexylamine N-oxide and N-dimethyloctylamine N-oxide were prepared by reaction of the corresponding tertiary amine with hydrogen peroxide (12). Both samples were isolated as crystalline solids and were >99% pure, based on acid/base titrations and spectrometric methods. Both samples were very hygroscopic. Reagent grade NaBr, 0.1 N and 2.0 N HC1 were from J.T. Baker Chemical Co. and the all solutions were prepared using distilled and deionized water. The pH was monitored using an Orion Ross combination pH electrode and an Orion EA 940 meter. 

Trimethylamine N-oxide, either anhydrous or as its readily available dihydrate, smoothly oxidizes a wide variety of alkyl, cycloalkyl, aryl and heterocyclic boron derivatives to the corresponding oiganyl-oxyboranes (equation 22) which, in Ae case of the dihydrate, are hydrolyzed in the reaction mixture. Anhydrous trimediylamine N-oxide is simply prepared and this reagent must be used for the oxidation of a enylboranes if prior hydrolysis is not to compete with oxidation. > Alkynylboranes are not oxidized by trimethylamine N-oxide. ... 

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