Electrooxidation of primary nitramine anions on platinum in MeCN

Abstract

Oxidation of primary, nitramine anions RNNO2-Bu~N + (R = ,'vie, Et, Pr i, or methoxyfurazanyl) in 0.1 N BuzNCIO a in MeCN on a Pt anode was studied by voltammetry and controlled potential electrolysis. It was found that the first stage of oxidation affords the corresponding radicals, which are further stabilized due to hydrogen abstraction from the medium. These radicals are also involved in other reactions, includi~g those, which yield azo derivatives. The possibility of generation of nitrene species in these reactions is discussed.Key words: electrooxidation of nitramine anions, nitrenes, azo compounds.Previously. I we examined the possibility of cathode deprotonation of primary, nitramines. As part of continuing studies of the electrochemical behavior of nitramines, in the present work we studied the regularities of electrooxidation of nitramine anions containing a donor or acceptor substituent at the amine nitrogen atom. Judging from the published data, these processes are still poorly understood. However, radical intermediates, which are probable intermediates in the oxidation of nitramine anions, could be considered as potential sources of nitrene species. ExperimentalThe voltammetric measurements were carried out in a temperature-controlled (25 ~ glass cell with cathode and anode compartments separated by a porous-glass filter. The polarization curves were recorded on a rotating disk Pt electrode (7.61 -10 -3 cm 2) using a P-5827M potentiostat. A graphite rod was used as the auxiliary, electrode and Ag/0.1 N AgNO 3 was used as the reference electrode.The coulometric measurements and microelectrolysis were carried out in the same cell. A platinum plate (2 cm 2) was used as the working electrode, but the polarization curves were recorded in the course of electrolysis using a rotating disk Pt electrode.The preparative electrolysis was performed ma sealed cell analogous to that described above (but of a la~er volume). A Pt plate (28 cnt 2) was used as the anode. The auxiliary and r:efei'ence ek/~:frodes were the san'ie as those used in the voltammetric measurements.A 0.1 N Bu4NCIO 4 solution in anhydrous MeCN was used as the supporting electrolyte in the voltammetric measurements and in the electrolysis. The working solution was deaerated with argon before the polarization curves were recorded and the electrolysis was performed.Dehydration of MeCN was performed by distillation over P205 (five times) followed by distillation over calcined K2CO 3.Methyl-, ethyl-, and isopropylnitramines were prepared according to procedures reported previously, z,3 Tetrabutylammonium salts of the above-mentioned nitramines were prepared by adding an equimolar amount of KOH to their methanolic solutions followed by cation exchange upon addition of the calculated amount of tetrabutylammonium perchlorate. The alkali salts were precipitated with acetone, the filtrates were concentrated in vacuo, and the residues were recrystatlized from organic solvents. 4-Amino-3-methoxyfurazan was prepared according to a known procedure. 't A proc...

Reactions of 3-amino-4-methylfurazan with nitrating agents

“…How ever, nitrеne 13 could arise upon the oxidation of nitr amine 2, as takes place in the electrolysis of nitramino furazans. 14 As an attempt to improve the outcome of nitration with NO 2 BF 4 , we carried out preliminary silylation of the amino group in compound 1 by the procedure we devel oped previously. 31 The nitration of the silyl derivative 14 Scheme 2 in CH 2 Cl 2 at -30 °C furnished nitramine 2 in 89-93% yield (Scheme 4).…”

“…10 The information on nitration of primary aminofurazans is limited. Nitramines can be obtained by reactions with N 2 O 5 , 11 HNO 3 (see Refs 5,[12][13][14][15], or NaNO 3 /H 2 SO 4 (see Ref. 10), HNO 3 /H 2 SO 4 (see Refs 5,13), and HNO 3 /AcOH (see Ref.…”

Comparative Theoretical Studies on Energetic Ionic Salts Composed of Heterocycle-Functionalized Nitraminofurazanate-Based Anions and Triaminoguanidinium Cation

“…The furazan, triazole, tetrazole, or tetrazine ring is a useful fragment to design energetic compounds because of its inherently high nitrogen content and good thermal stability. − The furazan derivatives have played a significantly diverse role as energetic components in the production of high explosives, solid propellants, and pyrotechnic gas generators. , Since the furazan ring lacks an acid proton and has electron-withdrawing character, it is impossible to serve as a cation or anion. − But the combination of the furazan with other acidic proton-containing energetic groups deprotonates anions. , Nitraminofurazans are known to be strong acids; thus, they are favorable for forming stable salts with metals and amines. − Compounds containing nitramino groups (−NHNO 2 ) are of interest in the design of high-energy ionic salts. ,, …”

Desilylative Nitration of C,N‐Disilylated 3‐Amino‐4‐methylfurazan.

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3,4-Bis(3-nitrofurazan-4-yl)furoxan has been synthesized by nitration of C,N-bis(trimethylsilyl) derivative of 3-amino-4-methylfurazan with nitrogen oxides. J. Heterocyclic Chem., 42, 1237.The reactions of 3-amino-4-methylfyrazan (1) with nitrating/nitrosating reagents have recently been shown to provide a very useful way for the amino group transformations in the preparation of nitramino-, nitro-, nitroso-, azo-, and azoxy-methylfurazans [1][2][3]. No reaction involving the methyl group of compound 1 has been described [4].In connection with our project dealing with the chemistry of 3-lithiomethyl-4-alkyl-furazans, we have been exploring the chemical reactivity of the intermediates as a versatile building block in organic synthesis [5][6][7][8].

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“…The reactions of 3-amino-4-methylfyrazan (1) with nitrating/nitrosating reagents have recently been shown to provide a very useful way for the amino group transformations in the preparation of nitramino-, nitro-, nitroso-, azo-, and azoxy-methylfurazans [1][2][3]. No reaction involving the methyl group of compound 1 has been described [4].…”