Furazans furoxans

Furazane (1,2,5-Oxadiazole) und Furoxane (Furazan-oxide) werden als Anhydride von 1,2-Dioximen bzw. als die entsprechenden N-Oxide durch Lithiumalanat zu 1,2-Diaminen reduziert z. B.8 ... 

A third example to illustrate the construction of G graphs is the furoxan-furazan rearrangement (see Scheme L8), Based on the principles outlined previously it is evident that this rearrangement can be pictured by the Go, Gi, G2, and G3, graphs as presented in Scheme 1.12. They also show the mirror plane symmetry. 

If the XPS spectra of impacted TATB, TNT, RDX, HMX, TNB and other explosives are considered, a common feature is that the nitro nitrogen is reduced in all cases and products with intermediate oxidation state like furoxans, furazans, nitrosos, nitrites, triazines etc are produced. Simultaneously the carbon atoms in the molecules become oxidized and of course water is produced. It appears that these reactions represent the pattern of decomposition of explosives in general. 

Heterocycles which provide the NOC or CNO component synthon Isoxazoles can be prepared by the thermal or photolytic cleavage of a number of heterocycles, such as 1,3,5-dioxazolidone, furazans, furoxans and 1,3,2,4-dioxathiazole 2-oxides, in the presence of a reactive alkene or alkyne. 

Naphtho[l, 2-c]furazans electrophilic reactions, 6, 410 synthesis, 6, 418 Naphtho[l, 2-c]furoxans eleetrophilic reactions, 6, 410 3-Naphthoic acid, 2-hydroxy-l-(2-thiazolylazo)-analytical uses, 6, 328 Naphtho[ 1,2-h]imidazoles oxidation, 5, 405... 

The action of hydroxylamine and sodium acetate in ethanol upon picryl chloride was stated to give 4,6-dinitrobenzofuroxan, and probably some of this compound was formed, although it was later shownthat much of the original work was faulty. A report that hydroxylamine and 2,4,5-trinitrotoluene give 5-methyl-6-nitro-benzofuroxan has been found to be incorrect. Benzofuroxan has not been prepared by V-oxidation of benzofurazan, and it seems unlikely that this could be achieved, since benzofuroxan itself is oxidizable by powerful reagents to o-dinitrobenzene (Section VI, B). A report of the oxidation by nitric acid of anthraceno[l,2-c]furazan to the furoxan is incorrectlv abstracted. 

Furazan 1 was first prepared and characterized in 1964 by melting glyoxime 2 with succinic anhydride in 57% yield (64JA1863, 65JOC1854). Its A-oxide, furoxan 3, has been in a focus of attention for chemists for more than a century, but was synthesized only in 1994 by oxidation of 2 with dinitrogen tetroxide in dichloromethane in 45% yield (94MC7) (Scheme 1). The A-oxide cannot be prepared by direct oxidation of furazan. 

Vinyl azides 50 (73CJC2406) and vicinal vinyl nitro compounds of type 51 (57JOC456, 75MI1) can be precursors for furoxans and furazans (Scheme 20). 

Nitrile groups attached to the furazan and furoxan rings are susceptible to nucleophilic reagents. The nitrile group was easily reacted with azides (68USP3386968,... 

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