Nitromethane reaction with

Many of the reactions involving a nitroalkane will proceed through the aci structure. Nitroalkanes react slowly with strong bases to form the nitronate salt. Nitromethane reaction with strong bases (e.g., sodium hydroxide) proceeds rapidly to form the sodium salt of methazonic aci. 

Sheads studied the reactivity of over 100 alcohols with 2,1-benzisoxazoles with 70% aqueous perchloric acid in nitromethane 74DIS(B)147). The rates of quaternization by reaction with Mel in DMSO were also studied and the dynamics of the reaction investigated <74AJC122l). 

A similar transformation results when trimethylsilyloxy-substituted allylic halides react with silver perchlorate in nitromethane. The resulting allylic cation gives cycloaddition reactions with dienes such as cyclopentadiene. The isolated products result from desilyla-tion of the initial adducts ... 

Although the base-catalyzed addition of nitroalkanes to electron-deficient olefins has been extensively used in organic synthesis fsee Michael addition Chapter 4, it is only recently that the reaction has been extended to the cyclopropanadon reaction. In 1978, it was reported that the anion of nitromethane reacts with certain highly electron-deficient olefins to produce cycloptopanesingoodyieldrEq. 7.36. More recently, this reaction has been extended to more general cyclopropanadons, as shown in Eqs. 7.37 and 7.38, in which potassittm salts of nitroalkanes are employed in DMSO as alkylidene transfer reagents." ... 

A proof for the formation of alkyl radicals was found by their addition to the aci-nitromethane anion (CH2=N02 ) and by their reaction with p-benzoquinone to give the optically active nitroalkane radical-anion and the semiquinone radicals, respectively. In the case of di-r-butyl sulfoxide the f-butyl radical was observed directly by its absorption spectra. 

The rate of the reaction with most reagents is proportional to the concentration of NO2, not to that of other species. When the reagent produces this ion in small amounts, the attack is slow and only active substrates can be nitrated. In concentrated and aqueous mineral acids the kinetics are second order first order each in aromatic substrate and in nitric acid (unless pure nitric acid is used in which case there are pseudo-first-order kinetics). But in organic solvents, such as nitromethane, acetic acid, and CCI4, the kinetics are first order in nitric acid alone and zero order in aromatic substrate, because the rate-determining step is formation of NOj and the substrate does not take part in this. 

Nitromethane gives rise to an extremely violent reaction with calcium hypochlorite. 

Other authors also determined by FTIR that organic nitrocompounds are formed as primary products of the NO CH4-SCR reaction on ZSM-5-based catalysts [121-124], They preadsorbed nitromethane on the sample placed in the IR cell and followed by IR its transformation into other intermediates under 02 and NO versus time at different temperatures. For Cu- and Co-ZSM-5, it was shown that around 300°C adsorbed nitromethane is easily converted into isocyanates and then melamine via polymerization of the former species. Both species easily interact with molecular oxygen, while no reaction with NO is observed and the reactivity depends on the temperature and the nature of the transition metal cation. 

Proazaphosphatrane, P(RNCH2CH2)3N, is an efficient catalyst for the Henry reaction, and various ketones give nitro-aldols by the reaction with nitromethane and other nitroalkanes (Eq. 3.20).21... 

Combining, in tandem, the nitro-aldol reaction with the Michael addition using thiophenol is a good method for the preparation of P-nitro sulfides as shown in Eqs. 4.2 and 4.3. This reaction is applied to a total synthesis of tuberine. Tuberine is a simple enamide isolated from Streptomyces amakusaensis and has some structural resemblance to erbastatin, an enamide which has received much attention in recent years as an inhibitor of tyrosine-specific kinases. The reaction of p-anisaldehyde and nitromethane in the presence of thiophenol yields the requisite P-nitro sulfide, which is converted into tuberine via reduction, formylation, oxidation, and thermal elimination of... 

Primary nitro ketones, ethyl nitroacetate, and (phenylsulfony l)nitromethane react with alkenes in the presence of Lewis acids to give nitrile oxide cycloaddition.61a Similarly, the reaction of a-nitro ketones with TeCl4 generates the corresponding nitrile oxides, as shown in Eq. 6.36.61b... 

Ono and coworkers have extended the radical elimination of v/c-dinitro compounds to P-nitro sulfones151 and P-nitro sulfides.138,152 As P-nitro sulfides are readily prepared by the Michael addition of thiols to nitroalkenes, radical elimination of P-nitrosulfides provides a useful method for olefin synthesis. For example, cyclohexanone is converted into allyl alcohol by the reaction shown in Eq. 7.110. Treatment of cyclohexanone with a mixture of nitromethane, PhSH, 35%-HCHO, TMG (0.1 equiv) in acetonitrile gives ahydroxymethylated-P-nitro sulfide in 68% yield, which is converted into the corresponding allyl alcohol in 86% yield by the reaction with Bu3SnH.138 Nitro-aldol and the Michael addition reactions take place sequentially to give the required P-nitro sulfides in one pot. 

Trioxymethylene, condensation with nitromethane, 41, 67 Triphenyldnnamylphosphonium chloride, from triphenylphosphine and cinnamyl chloride, 40, 36 reaction with benzaldehyde and lithium ethoxide to yield... 

Reaction of nitromethane and monosaccharide-derived dialdehydes is a useful tool that has been broadly used for the preparation of nitro and amino sugars, and carbocycles.30 Dialdehydes can easily be obtained by oxidative cleavage of conveniently protected monosaccharides with sodium periodate. Their subsequent Henry reaction with a nitroalkene, commonly nitromethane, usually gives isomeric mixtures that require the isolation of the major isomer.31 Thus, treatment of the D-ribose derivative 27 with sodium periodate gave dialdehyde 28, which was subjected to a Henry reaction with nitromethane, to afford nitrosugar 29 as an epimeric mixture (Scheme 11).32... 

In 1950 an alternative to the Sanger procedure for identifying N-terminal amino acids was reported by Edman—reaction with phenyl-isothiocyanate to give a phenylthiocarbamide labeled peptide. When this was heated in anhydrous HC1 in nitromethane, phenylthiohy-dantoin was split off, releasing the free a-NH2 group of the amino acid in position 2 in the sequence. While initially the FDNB method was probably the more popular, the quantitative precision which could be obtained by the Edman degradation has been successfully adapted to the automatic analysis of peptides in sequenators. 

Triphenylpyrylium tetrafluoroborate is a versatile and useful stable starting material. Its reaction with nitromethane under basic conditions has made 2,4,6-triphenylnitrobenzene easily available. In addition, pyrylium salts are readily converted to a variety of pyridine derivatives i i . 20 including alkyl- and arylpyridinium salts, to thiopyrylium salts," and to substituted azulenes. ... 

Besides solvation, a solvent can also participate in entrainment of ion-radical transformations. The reaction between tertiary aliphatic nitro compounds and the sodium derivative of nitromethane, NaCH2N02, is an example (Kornblum and Erickson 1981). To prepare NaCHjNOj, nitromethane is treated with sodium hydride. Then a tertiary aliphatic nitro compound is introduced into the solution formed. Several organic solvents were probed and CHjSOjCHj (DMSO) turned out to be the most effective. Kornblum and Erickson (1981) attributed this result to the formation of small amounts of NaCH2SOCH3 (sodium dimsyl) that was produced from DMSO as a result of its reaction with sodium hydride. Sodium dimsyl acts as a powerful one-electron reducer that induces the following chain anion-radical process ... 

A different behavior is exhibited by naphthalene-1,8-dicarbocal-dehyde (73). No m-naphthane derivatives are obtained on reaction with nitromethane, nitroethane or other methylene components. The basic medium, required for aldol type additions, causes the dialdehyde to undergo Cannizzaro reaction to the naphthopyranon (74) via an intramolecular 1,5-hydride shift, which is sterically favoured by the peri-position of the two aldehyde functions 28). 

For the cyclization of dialdehydes, however, its utility seems limited. Being a nitromethane addition product, it can readily undergo retro-nitromethane addition with alkali to give formaldehyde and nitromethane. Thus, it is not surprising that reaction of glutaraldehyde with 2-nitroethanol under the usual conditions (i.e. 1 molar equivalent of sodium hydroxide in aqueous ethanol) should yield 2-nitrocyclohexane-1,3-diol 5), a nitromethane cyclization product With catal5dic amounts of sodium hydroxide (pH 8—9), however, 1-hydroxymethyl-l-nitro-cyclohexane-2-6-diol (80) can be isolated in yields of 24—29%... 

Anodic oxidation of catechols enables the unstable quinones to be prepared and reacted in situ. Reaction of the 1,2-quinone with a 1,3-dicarbonyi compound gives a high yield of a benzofuran [123, 124]. Both 1,2- and 1,4-quinones, prepared electrochemically in nitromethane, are efficiently topped in Diels-Alder reactions with butadienes [125]. 

Di-/erJ-butylthianthrene and 1,3,6,8-tetra-tert-butylthianthrene were obtained from the diaryl sulfides in moderate yields by reaction with c. H2SO4 in nitromethane (68CB2956). A modified diaryl disulfide approach was based on intramoleculeir free radical substitution an o-phenoxy- (95% yield) or o-phenylthio-substituent (40% yield) being displaced as a radical (75G841). 

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