Nitromethane oxidation

In a route by Hoffman—La Roche workers [35] ring contraction of the cyclohexane dione (24) with sodium carbonate in mesitylene gave the cyclopentenone (25) which was elaborated to the lactone (26a) by 1,4 addition of nitromethane, oxidative cleavage of the allyl side chain, ketone reduction and lactonisation. 

Nitrations can be performed in homogeneous media, using tetramethylene sulfone or nitromethane (nitroethane) as solvent. A large variety of aromatic compounds have been nitrated with nitronium salts in excellent yields in nonaqueous media. Sensitive compounds, otherwise easily hydroly2ed or oxidized by nitric acid, can be nitrated without secondary effects. Nitration of aromatic compounds is considered an irreversible reaction. However, the reversibihty of the reaction has been demonstrated in some cases, eg, 9-nitroanthracene, as well as pentamethylnitrobenzene transnitrate benzene, toluene, and mesitylene in the presence of superacids (158) (see Nitration). 

This class was first reported in 1924 and was formed 62HC(17)l) by cyclization of a-bromo-/3-aryl-y-nitroketones. The direct synthesis by oxygenation of 2-isoxazolines has not been reported. To date only 3-substituted derivatives have been prepared. Aryl-nitromethanes react with nitrostilbene to form isoxazoline A-oxide by a nitrile ion displacement (Scheme 138) <62HC(17)1, 68TL3375). 

The chemical resistance of the linear polymers is also very good. Resistant to most acids, aqueous bases, hydrocarbons, most halogenated hydrocarbons, alcohols and phenols, they are attacked by concentrated sulphuric acid, formic acid, some amines, benzaldehyde, nitromethane and a few other reagents. They will dissolve in 1-chloronaphthalene at elevated temperatures but in general have excellent solvent resistance. The polymer is cross-linked by air oxidation at elevated temperatures. 

Copper, chromium, iron, most metals or their salts, any flammable liquid, combustible materials, aniline, nitromethane Fuming nitric acid, oxidizing gases Acetylene, ammonia (anhydrous or aqueous)... 

Nitric acid, 98 Nitric oxide, 98 Nitrilotriacetic acid, 98 p-Nitroaiiiline, 99 Nitrobenzene, 99 Nitrocarbono SA, 146 Nitrocellulose, 99 p-Nitrochlorobenzene, 99 Nitroethane, 99 Nitrofen, 99 Nitrogen, 99 Nitrogen dioxide, 99 Nitrogen oxides, 99 Nitrogen trifluoride, 99 Nitroglycerin, 100 Nitrokemia 200 Rt., 167 Nitromethane, 100 5-Nitro-o-anisidine, 99 5-Nitro-o-toluidine, 100 Nitrophenols, 100... 

In contrast to the stepwise oxidation of sodium hyponitrite in liquid N2O4, the oxidation goes rapidly to the nitrate ion in an inert solvent of high dielectric constant such as nitromethane ... 

The Nenitzescu process is presumed to involve an internal oxidation-reduction sequence. Since electron transfer processes, characterized by deep burgundy colored reaction mixtures, may be an important mechanistic aspect, the outcome should be sensitive to the reaction medium. Many solvents have been employed in the Nenitzescu reaction including acetone, methanol, ethanol, benzene, methylene chloride, chloroform, and ethylene chloride however, acetic acid and nitromethane are the most effective solvents for the process. The utility of acetic acid is likely the result of its ability to isomerize the olefinic intermediate (9) to the isomeric (10) capable of providing 5-hydroxyindole derivatives. The reaction of benzoquinone 4 with ethyl 3-aminocinnamate 35 illustrates this effect. ... 

Few other reactions of series of substituted pyridines have been investigated extensively. Dondoni, Modena, and Todesco have measured the rate of N-oxidation of a limited series of pyridines and found a good correlation with normal u-values with a p-value of — 2.23. The A-alkylation of pyridines with alkyl iodides in nitrobenzene has been studied by Brown and Cahn and by Clarke and Rothwell. Unfortunately, the only data available are for the parent compound and for alkyl derivatives, and, since the a-values for the various alkyl groups in a given position are substantially constant, this leaves a correlation of only three independent points. However, the rates of A-alkylation of the j8- and y-alkyl derivatives are so nearly equal that it appears as if no correlation existed. Clarke and Rothwell have also studied the alkylation with allyl bromide in nitromethane at various temperatures, and in this case a more extensive series is available. The authors state that no overall Hammett correlation is obtained however, the j8-substituted derivatives fall on one straight line and the y-derivatives on another one with a different slope. The data are shown in Fig. 2. The line for the j8-compounds, p = — 2.53 0.31, r = 0.95, is seen not to be very good the line for the y-derivatives, p = — 1.42 0.06, r = 0.99, is much more satisfactory. It does not seem likely that the discrepancy is due to the intervention of resonance effects, since in this case one would expect the correlation for the y-derivatives to be poorer than that for the j8-analogs. More extensive studies with a wider variety of substituents would seem very desirable. 

Base-catalyzed nitromethane cyclizadonof the thaldehyde generated by periodate oxidation of 1,3-O-cyclohexyhdene-myo-inositol affords the nitrodiol with l,4/3,3,5-coti iguration This is converted into the ct-marmosidase inhibitor, marmostadn A fEq 3 60 ... 

Nitric oxide, 80 Nitrogen, 79 correlation with CO, 39 Nitromethane, 219 Nitrosome thane, 149 Nonbondmg orbitals, 5, 9, 28 Norbomadiene, 282... 

To an ice-cold solution of the aldehydo sugar in CH,OH (ca. 25 mL per g) are added 3 equiv of nitromethane (or nitrocthane), followed by 2.9 equiv of sodium methoxide. After stirring for 2 h 45 min, the medium is neutralized by the addition of acidic Dowex 50, then filtered. Removal of the solvent by distillation and purification by chromatography on silica gel (Ei,0/hcxane) or on aluminum oxide (Et20) furnishes the product yield 85-99%. 

Starting from the appropriately substituted carbohydrates (e.g., II), 1,5-dialdehydcs are obtained by periodate oxidation. Subsequent double Henry reaction33 with nitromethane furnishes a variety of nitro-substituted carbohydrate derivatives. In most cases pure stereoisomers are obtained by crystallization of the reaction mixture3. 

IPN gave a ERDE gap test (Scale III) of 16 cards at ambient temp. A value of over 27 cards is indicative of positive sensy to the rifle bullet test. Refs as to gap sensy include ethylene oxide (10 cards), Nitromethane (24 cards) and ethyl nitrate (43 cards)... 

The transformation of l-methylthio-l-(methylsulfonyl)alkanes (254) to methyl esters can be efficiently carried out by oxidation or by a-chlorination followed by methanolysis (equation 152)145. The lithium or the sodium salt of (phenylsulfonyl)nitromethane (256) is a very useful reagent for the preparation of higher homologues of nitromethanes by alkylation since the salts are air insensitive, non-hygroscopic, and easily handled without decomposition. The oxidation of the resulting secondary a-nitro sulfone (257) gives... 

Diels-Alder reactions of quinones generated in situ by electrochemical oxidation in lithium perchlorate-nitromethane [105]... 

In the same way, the stability of nitromethane,nitroethane and 1-nitropropane are very much weakened by the presence of metal oxides. A study that was carried out on twenty four oxides showed that the most active are cobalt, nickel, copper and silver oxides and especially dichromium and diferric trioxides, which cause nitroethane to detonate at 245°C. 

The interaction between nitromethane, the etherate of boron trifluoride and silver oxide gives rise to an extremely dangerous reaction. However, it is difficult to interpret it. Can it be explained by the unstable property of silver tetrafluoroborate or the destabilising effect of boron trifluoride on nitromethane ... 

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