Dinitromethane, acidity

Rahman and Clapp decomposed dinitromethane derivatives in DMF in the presence of alkenes to obtain 2-isoxazolines. Without any alkene present, an acid and KNO2 were obtained. They proposed a mechanism which proceeded via a three-membered ring or a nitrocarbene which rearranged to a nitrile oxide (76JOC122, 75MI41612). 

The dinitromethane derivatives 135 and 136 were obtained by nitration of oximes of monoacyl furazans and furoxans with dinitrogen tetroxide [36G819, 37G518, 63T(S)143] or nitric acid (37G388, 97MI11, 97ROC1760) (Scheme 79). 

A potential industrial route to potassium dinitromethane (18) involves treatment of methyl malonate (107) with red fuming nitric acid to give methyl Q ,Q -dinitroacetate (108), followed by hydrolysis-decarboxylation with aqueous potassium hydroxide. Dinitromethane is a precursor to 2,2-dinitroethanol and 2,2-dinitro-1,3-propanediol, both of which are useful in addition and esterification reactions for the production of energetic oligomers and plasticizers. 

Dinitromethane has two acidic protons and reacts with Michael acceptors to form bis-adducts. " Secondary nitroalkanes can only react with one equivalent of Michael acceptor. In the absence of steric effects primary nitroalkanes usually react with two equivalents of Michael acceptor to form bis-adducts. Depending on the reaction stoichiometry, 1,4-dinitrobutane can be reacted with methyl acrylate to form either the bis-adduct (129) or the tetra-adduct (130) in good yield. " ... 

Primary and secondary nitroalkanes, dinitromethane, and terminal em-dinitroaliphatic compounds like 1,1-dinitroethane, all contain acidic protons and have been used to generate Mannich products. Formaldehyde is commonly used in these reactions although the use of other aliphatic aldehydes has been reported. The nitroalkane component is frequently generated in situ from its methylol derivative, a reaction which also generates formaldehyde. Ammonia, " aliphatic amines, " hydrazine, and even urea have been used as the amine component of Mannich reactions. 

Dinitromethane is a volatile liquid with a sharp, acid smell. It was first obtained by Villiers [41] and Losanitsch [42] ... 

When the author nitrated 4,6-dihydroxy-2-methylpyrimidine with mixed acids and the intermediate hydrolyzed, equal amounts of potassium dinitromethane and 1,1-diamine-2,2-dinitroethene were formed. 

Hq 1.471 at 20° stable at —20° sol in w, eth corrosive to skin prepd by acidification with sulfuric acid of the potas-sol in w, eth corrosive to skin prepd by acidification with sulfuric acid of the potassium salt of the [Pg.52]

Suitable condensing agents for this reaction are acetic anhydride,259,260 hydrogen chloride and thionyl chloride,261 dicyclohexylcarbodiimide,262 and phosphorus pentaoxide.263 For example, barbituric acids, 2-hydroxy-1,4-naphthoquinone, and methylene di(phenyl sulfone),259 malonodinitrile,261 Meldrum acid and 2,3-indenedione,262 dinitromethane and dihydroresorcinol260 yield ylides by this method. 

At the present time (2006) the preferred starting material for the manufacture of FOX-7 is 4,6-dihydroxy-2-methylpyrimidine, despite the fact that for every 10 kg of FOX-7 there is > 5 kg of unwanted dinitromethane produced as a by-product and two equivalents of nitric acid are wasted. It would obviously be preferable if these disadvantages could be avoided and consequently the nitration of a munber of other, closely related heterocycUc systems has been studied as potential alternative precursors [40-42]. These were chosen because they were imable or imlikely to nitrate at position 5. Perhaps the most obvious candidate to investigate was 6-methyl-l,3,5-triazine-2,4(lff,3ff)-dione (20), since this molecule has nitrogen instead of carbon between the carbonyl groups. 

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