Nitromethane, functionalization

Simple ketones and esters are inert. On the other hand, nitroalkanes react smoothly in r-butyl alcohol as a solvent with butadiene, and their acidic hydrogens are displaced with the octadienyl group. From nitromethane, three products, 64, 65, and 66, are formed, accompanied by 3-substituted 1,7-octadiene as a minor product. Hydrogenation of 65 affords a fatty amine 67 which has a primary amino function at the center of the long linear chain[46,61]. 

A remarkable diastereoselectivity is observed when nitromethane is added to aldehydo sugars of type 7 which carry no oxygen function at C-3 on the a-face13. 

Recently, enantioselective organo-catalytic procedures for the aza-Henry reaction have been disclosed. The presence of either an acidic or a basic function appears to be a requisite of the catalyst. In fact, the condensation of ni-tromethane with M-phosphinoyl arylimines 72 is catalyzed by the chiral urea 85 derived from (R,R)-l,2-diaminocyclohexane and gives the product (R)-74 with good yield and moderate enantioselectivity (Scheme 15) [50]. The N-phosphinoyl substituent is determinant, as the addition of nitromethane to the N-phenyl benzaldimine failed and the reaction of the N-tosyl ben-zaldimine gave the expected adduct with quantitative yield but almost no... 

Among other compounds, methyl nitrate, nitromethane, ethyl nitrate and tetrafluo-rohydrazine function as promoters of spontaneous ignition of mixtures of methane or propane with oxygen and argon. 

The anion of nitromethane adds easily to the carbonyl functions of sugars. This is a useful strategy for extension of the carbon chain.100 2-Acetamido-2-deoxy-P-D-glucose (A-acetyl-D-glucosamine) is the carbohydrate unit of glycoproteins that occurs most often. The nitromethy-lation method provides a straightforward route to a series of C-glycosyl compounds with the acetamido functionality (Eq. 3.62).101... 

Heterobimetallic asymmetric complexes contain both Bronsted basic and Lewis acidic functionalities. These complexes have been developed by Shibasaki and coworkers and have proved to be highly efficient catalysts for many types of asymmetric reactions, including catalytic asymmetric nitro-aldol reaction (see Section 3.3) and Michael reaction. They have reported that the multifunctional catalyst (f )-LPB [LaK3tris(f )-binaphthoxide] controls the Michael addition of nitromethane to chalcones with >95% ee (Eq. 4.140).205... 

In some cases, no cycloalkylation is observed by the reaction of nitromethane with electron-deficient olefins with cyano and methoxycarbonyl groups. The reaction affords new, highly functionalized cyclohexenes in the presence of catalytic amount of piperidine under solvent-free conditions with focused microwave irradiation (Eq. 7.41).42... 

The telomer of nitromethane with four moles of butadiene 62 has a chain of 17 carbons, and this compound is a very suitable starting material with right carbon numbers and necessary functionalities for the synthesis of civetone (133), a naturally occurring fragrant compound. The telomer was converted into civetonedicarboxylic acid (132) by the following sequence of reactions ... 

Biocides that function as formaldehyde-releasers comprise about 60 % of total sales of antimicrobials (29). Thus, such antimicrobials are expected to be common additions to metalworking fluids. Examples of formaldehyde-releasing antimicrobials are tris(hydroxy methyl) nitromethane, trivially called tris nitro, 4,4 -(2-ethyl-2-... 

Secondary nitro compounds can be converted into carbanions in similar fashion. Interesting highly functionalized adducts (46) were prepared by addition to levoglucosene (45) (equation 17)59. Mixtures of diastereomeric adducts were generally formed60. The adduct from nitromethane undergoes double Michael addition followed by aldol condensation to afford the novel adduct 47. 

The logarithm of the rate coefficient is a linear function of the donicity of dichloromethane, nitromethane, benzonitrile, and acetonitrile (Fig. 16). Deviations in the DN—log fc12 plot are found for solvents with viscosities > 2 cP. The deviation is noticeable for solvents of viscosities between 2 and 3 cP (TMP 2.32 cP, PDC 2.83 cP) and is more pronounced for a solvent of considerably higher viscosity such as phenylphosphonic dichloride (4.10 cP) (Fig. 16). 

Chemical/Physical. Nitromethane will not hydrolyze because it does not contain a hydrolyzable functional group. 

The extension of this reaction to nitromethane homologues was an obvious development, since it would provide a simple route for the simultaneous introduction of a nitro (or amino) function and an alkyl branch into a carbocyclic or pyranoside ring, to give compounds of type 2 and 3 respectively, that are as yet otherwise inaccessible. 

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). 

Papai et al. selected as model reaction the addition of 2,4-pentanedione (acetylacetone) to trans-(R)-mtrostyvQnQ, catalyzed by the bifunctional thiourea catalyst shown in Scheme 6 [46]. The analogous Michael-addition involving dimethyl malonate and nitroethylene as substrates, and a simplified catalyst was calculated at the same level of theory by Liu et al. [47]. Himo et al. performed a density functional study on the related cinchona-thiouTQa catalyzed Henry-reaction between nitromethane and benzaldehyde [48]. 

Scheme 6.146 Representative adducts obtained from the asymmetric Henry reaction between nitromethane and (hetero)aromatic aldehydes under bifunctional catalysis of C6 -thiourea-functionalized cinchona alkaloid 131.

Beyer and coworkers later extended these reactions to platinum clusters Ptn and have demonstrated that similar reaction sequences for the oxidation of carbon monoxide can occur with larger clusters [70]. In addition, they were able to demonstrate poisoning effects as a function of surface coverage and cluster size. A related sequence for Pt anions was proposed by Shi and Ervin who employed molecular oxygen rather than N2O as the oxidant [71]. Further, the group of Bohme has screened the mononuclear cations of almost the entire transition metal block for this particular kind of oxidation catalysis [72,73]. Another catalytic system has been proposed by Waters et al. in which a dimolybdate anion cluster brings about the oxidation of methanol to formaldehyde with nitromethane, however, a rather unusual terminal oxidant was employed [74]. 

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