Nitromethane in condensation with

Nitrogen, purification of, 41, 97 Nitromethane in condensation with formaldehyde, 41, 67 1-Nitro-l-methylcyclohexane, 43, 89... 

This method of reductive cyclization is most important for the synthesis of simple pyrrolizidine homologues. It was used also in the synthesis of 1-hydroxymethylpyrrolizidine reported by Leonard and Felley.46 Nitromethane when condensed with ethyl y-acetoxycroton-... 

Sodium methanenitronate reacts with phenyl isocyanate in benzene to give the readily separable sodium salts of nitroacetaniUde and nitromalondiarkhde. Except as the salt, nitromethane is unreactive with phenyl isocyanate at temperatures up to 100°C the higher homologues do not give condensation products that can be isolated. 

Trimethylsilyloxy-p-nitrostyrene was the target of Knoevenagel condensation of 2-trimethyl-siloxybenzaldehyde with nitromethane in the presence of -butylamine as base. NMR spectra 20 were obtained from the product of the reaction. What has happened ... 

MISCELLANEOUS BENZOHETEROCYCLES Partial reduction of lactone 166 (using for example diisobutylaluminum hydride in the cold) affords lactol 167. Condensation with nitromethane leads to the corresponding alkylated tetrahydrobenzopyran 170. The sequence probably starts by aldol reaction of the hydroxylactone form of the lactol (168) with nitrome thane to give the vinyl nitro intermediate 169 ... 

Henry reactions of nitro sugars can be promoted by catalytic amounts of mild bases and it has widely extended the use of triethylamine. A recent example involves the condensation of sugar derived a,p-unsaturated aldehyde 15 with nitromethane in the presence of triethylamine, to give... 

As in the case of other groups which activate adjacent CH6, the nitro group in aliphatic nitro compounds soon acquired importance in preparative organic chemistry, particularly for condensation reactions. The condensing agents are normally bases. Thus nitromethane will react with benzaldehyde to give first a nitro-alcohol and then a nitro-olefin (Priebs, 188425) ... 

The reaction between formaldehyde and compounds containing acidic protons is probably the most important route to polyols. Some of these polyols have been 0-nitrated and used as practical explosives. The condensation of nitromethane and nitroethane with excess formaldehyde in the presence of potassium hydrogen carbonate yields tris(hydroxymethyl)nitromethane (58) and l,l-bis(hydroxymethyl)nitroethane (60) respectively. The nitration of (58) and (60) with either absolute nitric acid or mixed acid gives the secondary high explosives, (59) and (61) respectively. 

Various nitro compounds have been condensed with carbonyl compounds in reactions catalyzed by alkaline earth metal oxides and hydroxides 145). It was found that the reactivities of the nitro compounds were in the order nitro-ethane > nitromethane > 2-nitropropane, and those of carbonyl compounds were propionaldehyde > isobutyraldehyde > pivalaldehyde > acetone > benzaldehyde > methyl propionate. Among the catalysts examined, MgO, CaO, Ba(OH)2, and Sr(OH)2, exhibited high activity for nitroaldol reaction of nitromethane with propionaldehyde. In reactions with these catalysts, the yields were between 60% (for MgO) and 26% (for Sr(OH)2) at 313 K after 1 h in a batch reactor. On Mg(OH)2, Ca(OH)2, and BaO, the yields were in the range of 3.8% (for BaO) and 17.5% (for Mg(OH)2). Investigation of the influence of the pre-treatment... 

The nucleophilic aromatic substitution of 6-nitropiperonal with [ F]K(Kryptofix 2.2.2)F yielded 6-[ F]fluoropiperonal that was condensed with nitromethane. Reduction and subsequent hydrolysis of the intermediate nitroalkene provided the target compound 6-[ F]FDA. In comparison to more direct approaches which utilize electrophilic aromatic substitution with positive polarized p F]fluo-rine [140-142], this type of preparation is characterized by high specific radioactivity, which is requested for human PET studies with vasopressor compounds, like 6-FDA [139,143]. 

Halide 32 was used first, in nitromethane-benzene solution in the presence of an equimolar proportion of mercuric cyanide. It was found83 that 32 gave a disaccharide at 0-6 of a protected derivative of 2-acetamido-2-deoxy-D-glucose in good yield, with a certain degree of stereoselectivity (a /3 ratio 7 3). Complete stereospecificity was attained, leading to the desired a-linked disaccharides, when the partially acylated bromide 33 was condensed with a number of different nucleophiles.66,83,84,93-95 A mechanism was postulated83 to explain the... 

Gronowitz found the Pictet-Spengler reaction a convenient route for the preparation of (259 equation 22) (70AK(32)217). Thiophene-3-carbaldehyde was condensed with nitromethane to give w-nitrovinylthiophene. Reduction of the nitro derivative with LAH afforded the /3-(thienyl)ethylamine. The condensation of this amine with formaldehyde to the corresponding imine followed by cyclization with hydrochloric acid proceeded very smoothly and in high yield. The aromatization was achieved with potassium ferricyanide in an alkaline dioxane-water mixture. 

NIBTN was first prepd by Hofwimmer(Refs 1 2) by condensation of 3 moles of formaldehyde with 1 mole nitromethane in the presence of KHCOj and subsequent nitration of the product. Modifications of this method are described in Refs 3,4,5,6,10 15. Aaronson(Ref 8) investigated the methods existing prior to-1941 and came to the conclusion that Stettbacher s method(Ref 5) was the best... 

This explosive was first described in 1912 by Hofwimmer118 who prepared it by the condensation of three molecules of formaldehyde with one of nitromethane in the presence of potassium bicarbonate, and by the subsequent nitration of the product. 

The condensation of nitromethane with formaldehyde is not typical of the general reaction since more than one molecule of formaldehyde tends to condense with one molecule of nitromethane even in the presence of a large excess of the latter. When equimolar quantities of formaldehyde and nitromethane are allowed to react the following approximate percentages of the three possible condensation products are obtained 1 ... 

Since many nitrogen-containing organic compounds are explosive, some mention is appropriate here of possible hazards in working with nitromethane. Occasionally, some evidence of decomposition, in the form of mild evolution of heat and gases, has been observed by the author in concentrated, acidified aldose-nitromethane reaction residues from which the bulk of the nitroalcohols had been separated. Such residues usually have been either discarded at once or stored at —20° when further crystallization was anticipated. Generally, it may be stated that the aldose-nitromethane condensation reaction does not involve serious explosion hazards. 

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