The review is devoted to modern trends in the chemistry of nitrogen-, oxygen-and sulfur-containing monocyclic, polynuclear and benzo(hetero)annulated heterocyclic compounds. Methods for the synthesis and chemical reactivity of furazan, furoxan, thiazole, thiadiazole, dithiazole, thiophene, glycoluril, imidazotriazine, diaziridine and other heterocycles are discussed. Characteristic features of reactions depending on the structure of the starting compounds, intermediates and reaction medium (organic solvents, ionic liquids) and mechanistic aspects of the most interesting transformations are considered. Data on the biological activities and prospects for practical applications of the indicated heterocyclic systems are presented.
The bibliography includes 383 references.
Novel high-density oxidizer based on highly nitrated bipyrazole was developed. It is the champion among heteroaromatic CHNO compounds with a density equal to 2.021 g cm−3 at room temperature.
A new family of energetic compounds, nitropyrazoles bearing a trinitromethyl moiety at the nitrogen atom of the heterocycle, was designed. The desirable high-energy dense oxidizers 3,4-dinitro- and 3,5-dinitro-1-(trinitromethyl)pyrazoles were synthesized in good yields by destructive nitration of the corresponding 1-acetonylpyrazoles. All of the prepared compounds were fully characterized by multinuclear NMR and IR spectroscopy, as well as by elemental analysis. Single-crystal X-ray diffraction studies show remarkably high density. Impact sensitivity tests and thermal stability measurements were also performed. All of the pyrazoles possess positive calculated heats of formation and exhibit promising energetic performance that is the range of 1,3,5-trinitroperhydro-1,3,5-triazine and pentaerythritol tetranitrate. The new pyrazoles exhibit positive oxygen balance and are promising candidates for new environmentally benign energetic materials.
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