Preparation of nitramines and nitramides

The paragraphs below describe only the preparations of A-nitro compounds that involve formation of an N-N bond (i) the preparation of primary aliphatic nitramines and nitramides by direct nitration or by nitrolysis of A,A- 

Properties and reactions of nitramines Secondary nitramines are neutral, primary nitramines form salts with bases, but an excess of alkali often causes decomposition to the carbonyl compound, nitrogen, and water. Secondary nitramines and aqueous alkali afford nitrous acid, aldehyde, and primary amine. Acids decompose primary aliphatic nitramines with formation of nitrous oxide in a reaction that has not yet been clarified thus these compounds cannot be hydrolysed by acid to amines in the same way as nitrosamines, although, like the latter, they can be reduced to hydrazines. Primary and secondary aromatic nitramines readily rearrange to C-nitroarylamines in acid solution. Most nitramines decompose explosively when heated, but the lower aliphatic secondary nitramines can be distilled in a vacuum. 

Particular care is required with the nitrations by acetic anhydride-nitric acid mixtures described below, since the acetyl nitrate formed has repeatedly caused violent explosions. Alkyl nitrates may also explode unexpectedly. 

A-Nitromethylamine 229 A-Methyl-p-toluenesulfonamide (23 g) is added portionwise, with stirring, to 70% nitric acid (130 ml) at 5°. When all the amide has dissolved, 98% nitric acid (130 ml) is added at 0° with stirring which is then continued for a further 10 min at 0°. Finally the mixture is poured into ice-water, and the A-methyl-A-nitro-p-toluenesulfonamide is filtered off and crystallized from ethanol it then has m.p. 57° (21 g, 73%). 

Piperidine (10 g) is added to a solution of the nitramide (10 g) in acetonitrile (35 ml) stirred at 5-10° the mixture becomes distinctly warm it is boiled under reflux for 30 min and then poured into 10% sodium hydroxide solution (100 ml). The precipitated 1-tosyl-piperidine is filtered off and the filtrate is acidified cautiously and extracted with ether. The extract is dried and evaporated and the nitramine is distilled in a vacuum. Yields are between 81% and 96%. 

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