A Green and Facile Approach for Synthesis of Nitro Heteroaromatics in Water

Abstract

A convenient and green method for the oxidation of nitrogen-rich heterocyclic amines to nitro-substituted heteroaromatics using potassium peroxymonosulfate (2KHSO 5 •KHSO 4 •K 2 SO 4 , Oxone) in water was developed. This method has several advantages over previous methods: operational simplicity, safety, inexpensive reagents, the use of H 2 O as the sole solvent, and mild conditions. The utility of the present oxidative system was demonstrated by the synthesis of the important energetic compounds 3,4,5-trinitro-1H-pyrazole (TNP) and 5-amino-3-nitro-1H-1,2,4-triazole (ANTA).

Recent Advances in Synthesis and Properties of Nitrated-Pyrazoles Based Energetic Compounds

“…Among these solvents, benzonitrile was always preferred to be the rearrangement medium since anisole could require an excessively long time and n-octanol would lead to poor-quality product. In 2014, Zhao et al [44] reported one convenient and green approach to synthesizing the 3-NP. They chose the oxone as the nitration agents of 3-aminopyrazole and water as the solvent (Figure 1, Scheme B).…”

“…From Table 8, these compounds were less sensitive than RDX, and did not exhibited excellent detonation properties. Yin et al [95] synthesized a family of 4-amino-3,5-dinitro-1H-pyrazol-1-ol (44) and its ionic derivatives (44a-f) ( Figure 17 N-oxidation of nitrogen-rich heterocycles including transformation of amino group to nitroso, azoxy, or nitro groups is another approach to designing HEDMs, which opens new avenues for the development of HEDMs [92,93]. The efforts to developing N-oxidation of dinitropyrazoles have been made recently.…”

“…From Table 8, these compounds were less sensitive than RDX, and did not exhibited excellent detonation properties. Yin et al [95] synthesized a family of 4-amino-3,5-dinitro-1H-pyrazol-1-ol (44) and its ionic derivatives (44a-f) (Figure 17, Scheme B). Except 44·H2O, all the compounds (44a-f, and 45) with thermal decomposition temperatures (169-216 °С) shown good balance between detonation properties and insensitive properties as shown in Table 8.…”

“…It is necessary to explore novel synthesis method. Zhao et al [44] used LLM-116 as starting material, water as solvent, and KHSO 5 as oxidant to synthesize TNP. Ravi et al [103] put forward the nitration system of metal nitrate and studied the process of nitration to TNP.…”

Synthesis of 3-Substituted 2,1-Benzisoxazoles by the Oxidative Cyclization of 2-Aminoacylbenzenes with Oxone

“…Recently, Oxone was employed as a green oxidant (in water) of nitrogen-rich heterocyclic amines to give the corresponding nitroaromatics via the production of a hydroxylamine intermediate. 13 Oxone over silica gel or alumina was also found to oxidize primary and secondary amines into the corresponding hydroxylamines. 14 Hence, we envisaged that the in situ generation of the hydroxylamine function by the oxidation of the starting 2-aminoacylbenzenes 1 would allow the selective attack on the carbonyl in a subse-are focused on supramolecular and organometallic chemistry.…”