3‐Nitromethyl‐pyrazoles from 2‐Cyano‐3‐methylthio‐4‐nitrocrotonic Acid Derivatives2‐Cyano‐3‐methylthio‐4‐nitrocrotonic Acid Derivatives1a,breact with hydrazines to form the 5‐amino‐3‐nitromethyl‐pyrazoles2a–cand the 5‐nitromethyl‐pyrazol‐3‐one3respectively. Contrary to this carboxylic hydrazides attacks the nitro group. For the resulting products the structure of pyrrol‐2,5‐dione oximes4is proposed. On the similar way from 3‐methylthio‐4‐nitro‐2‐phenylcrotononitrile1cand phenylhydrazine the pyrrol‐2,5‐dione hydrazone5arises. Subsequent reactions of2yield 3‐nitromethyl‐pyrazole derivatives6, 3