Four Syntheses of 4‐Amino‐3,5‐dinitropyrazole

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.