An alternative synthesis of the insensitive energetic nitramine 2-nitroimino-5-nitrohexahydro-1,3,5-triazine (1) via nitrolysis of a tertiary amine is presented. Nitration of the tertiary amine precursor (2) is effected by chloride-assisted elimination of the tert-butyl moiety, with the chloramine presumably formed as an intermediate. The reaction fails to proceed in the absence of chloride at 0 degrees C, however, its inclusion in the reaction system leads to a smooth conversion to (1) under mild nitrating conditions, which can be scaled up to yield multigram quantities. This is the first known example of a chloride-assisted nitrolysis of a tertiary amine to appear in the open literature.