Synthesis and investigation of isomeric mono- and dinitro derivatives of 3-methyl-4-(pyrazol-3-yl)furazan

Synthesis of 1-(N-nitropyrazolyl)-1Н-tetrazoles – a new type of heteronuclear N-nitropyrazole derivatives

“…The competing multidirectional effects of metasubstituents in the case of 5(3)-alkyl-3(5)-aryl(trifluoromethyl)pyrazoles allow us to conclude that the direction of N-nitration is mostly determined by the aryl group, leading to the formation of 3-aryl-1-nitropyrazoles. 38,43 At the same time, N-nitration in the series of 3(5)-R-5(3)-nitropyrazoles occurs at the nitrogen atom most distant from the nitro group, regardless of the nature of substituent R. 14,30 The data obtained in this work show that the reactivity of 1-pyrazolyltetrazoles fully corresponds to these trends. The dominant effect on N-nitration in the series of 1-(pyrazol-3 (5)-yl)tetrazoles 2, 3 is that of the 3(5)-tetrazole substituent, which leads to the formation of 1-(1-nitropyrazol-3-yl) tetrazoles 5a-j.…”

“…We observed a similar difference in N-nitration of pyrazoles also in some earlier experiments. 30 However, as far as we know, no systematic comparison of the nitrating efficiency of these acyl nitrates has been performed yet.…”

“…18 One of the current trends in the chemistry of exogenous NО donors 19 is the synthesis of hybrid molecules 20 that may combine the ability to release NO with other types of biological activity. [21][22][23][24][25][26][27][28] Of particular interest among such compounds is a fairly rare type of heteronuclear hybrid molecules [29][30] consisting of a five-membered aromatic heterocycle linked to a N-nitropyrazole core.…”

Novel Melt‐Castable Energetic Pyrazole: A Pyrazolyl‐Furazan Framework Bearing Five Nitro Groups

“…It adopts nonplanare nvironment apparently due to steric repulsion between substituents. The angle between furazan and pyrazole rings is equal to 53.49(4)8;t orsion angles that define orientation of the nitro groups at thep yrazole ring are equal to 103.5(2) and À0.7(2)8 for C2ÀC1ÀN6ÀO7 and C1ÀC2ÀN7ÀO9 angles, respectively.F or comparison, in Nunsubstituted derivative 4 [12],t he same angles are somewhat different being 66.7, À170.7, and 29.18 that can be attributedt ot he influence of the crystal packing. This demonstrates lability of nitropyrazole conformations -p rerequisite of dense crystal packing.…”

“…Keywords: Dinitropyrazoles · Furazan · Trinitromethyl · Crystal density · Melt-castable explosive S Sh ho or rt t C Co om mm mu un ni ic ca at ti io on n Efforts in this research group have recently focused on the development of oxygen-rich energetic pyrazoles [10,11]. Because of the preferable C/H/N/O composition, heat of formation and inherent chemical and thermal stability of the pyrazolyl-furazan core, 3-(3,4-dinitro-1H-pyrazol-5-yl)-4-methylfurazan (4) [ 12] was viewed as an attractive precursor for the design of new melt-castablee nergetic materials. In this case, the location of methyl group to the furazan ring provided the optimal combination of properties.…”