No abstract

in Wiley Online Library (wileyonlinelibrary.com).In this paper, syntheses of 4-amino-3,5-dinitropyrazole from four different starting materials are described. The starting materials were 4-nitropyrazole, 4-nitro-3,5-dimethylpyrazole, 3,5-dinitropyrazole, and 4-chloropyrazole, respectively. They are compared in terms of yield, number of steps and suitability for scale-up into pilot scale production. The overall yield, calculated from commercially available starting materials, ranged from 21% in the case of synthesis via 3,5-dinitropyrazole up to 61% for the one starting from 4-chloropyrazole. With numerous factors taken into account, the latter was chosen for a pilot scale study and the product could be produced in batches of 200 g.

The synthesis of 1,1-diamino-2,2-dinitroethene (FOX-7) by nitration of 4,6-dihydroxy-2-methylpyrimidine and hydrolysis of the resulting intermediate 2-dinitromethylene-5,5-dinitropyrimidine-4,6-dione has been studied. By varying the reaction parameters the optimal conditions for the synthesis of FOX-7 have been identified and gave a >90% yield of the pure product. The optimised process allowed the spent acid to be recycled without loss of yield, with almost stoichiometric consumption of nitric acid. The purity of the FOX-7 has been determined using a newly developed HPLC method

Treatment of 1,1-diamino-2,2-dinitroethene (FOX-7) with a variety of amines and hydrazine, results in at least one, and in some cases both, of the amino groups being replaced to give N-substituted and N,N'-disubstituted 1,1-diamino-2,2-dinitroethenes.

A two-stage conversion of 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazaisowurtzitane to 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, involving nitrosation followed by nitration, is described. It is shown that the purity of the final product obtained by this method is superior to that obtained by the reported one-pot method. Nitrosation of 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazaisowurtzitane in acetic acid is considered to be safer than nitrosation in pure dinitrogen tetroxide.