Synthesis and scale-up of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane from 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW, CL-20)

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, tane in acetic acid is considered to be safer than nitrosation in pure dinitrogen tetroxide.