Hydrazine is a useful building block in organic synthesis of pharmaceuticals and pesticides. One example is 3-amino-1,2,4-triazole and another is maleic hydrazide. The antitubercular drug isoniazid is prepared from hydrazine.ydrazine can arise via coupling a pair of ammonia molecules by removal of one hydrogen per molecule. Each H 2 N-N subunit is pyramidal in shape. The N-N single bond distance is 1.45 A (å 145), pm and the molecule adopts a gauche. Conformation the rotational barrier is twice that of. ethane