3-nitro-4- furazan

Bei der Oxidation von 3-Amino-furazanen mit Dihydroperoxid/Trifluoressigsaureanhydrid werden 3-Nitro-furazane erhalten, die durch direkte Nitrierung nicht zuganglich sind260,261 ... 

Zu Detonation skin etik und -eigenschaften von Amin o-nitro-furazan-2-oxiden132 und 3-Methyl-4-nitro-furazan-2-oxid s. Lit.133. 

Aus Propen und Distickstofftrioxid bzw. -tetraoxid wird das explosive 3-Methyl-4-nitro-furazan-2-oxid erhalten246 ... 

Die regiospezifische Synthese von 3-Aryl-4-nitro-furazan-2-oxiden gelingt durch Umset-zung von 2-Aryl-1-nitro-ethenen mit Distickstofftrioxid dabei werden - vermutlich iiber die Pseudonitrosite und die tautomeren Monoxime und Nitrolsauren - direkt die Furazan-2-oxide gebildet251 ... 

Zur thermischen Isomerisierung von 4-Aryl-3-nitro-furazan-2-oxiden zu 4-Nitro-3-aryl-fu-razan-2-oxiden373 (78 85%) s. Lit. ... 

Grundsatzlich sind aus Nitro-furazan-2-oxiden eine Reihe weiterer Verbindungen durch nukleophilen Austausch zuganglich. So erhalt man aus 4-Nitro-3-phenyl-furazan-2-oxid mit Natriumazid in Dimethylsulfoxid 4-Azido-3-phenyl-furazan-2-oxid (94%)416. 3-Methyl-4-ni-tro-furazan-2-oxid ist explosiv. 

Acetaldoxime, 2-(furazan-3-yl)-2-nitro-synthesis, 6, 409 Acetals vinyl... 

Furazans, methylvinyl-synthesis, 6, 412 Furazans, nitro-reactions, 6, 413-414 Furazans, phenyl-halogenation, 6, 412 nitration, 6, 412 NMR, 6, 397 Furazol, 7, 401 Furazolidone, 6, 233 as antibacterial agent, 1, 180 growth permittant veterinary use, 1, 220 veterinary use, 1, 208... 

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. 

The furazan ring is stable under the conditions used to reduce the nitro group to the amine (Scheme 6). Thus, on treatment of compound 19 with SnC in HCl, the nitro group was reduced and the cyano group underwent hydrolysis and decarboxylation yielding salt 20 (30G721). 

Elimination of the hydroxyaminomethyl moiety from nitro oxime 15 by treatment with a diazonium salt gave hydrazone 43 (75LA1029) (Scheme 15). The same product was obtained by coupling the diazonium salt with the compound 16. On heating in aniline, oxime 15 was transformed into Schiff base 42. Acylation of the oxime 15 with benzoyl chloride in pyridine led to a mixture of furazan 44 and dinitrile 45. 

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

A new eonversion of an aetivated nitro group at furazan ring into halogen was reported by Sheremetev et al. (000MC67) (Seheme 92). When dinitrofurazans 165a-c were allowed to reaet with an exeess of Vilsmeier reagent in POCI3 on... 

Nitration of the phenyl group in furazan 163 and furoxans 157c and 158c with 90% nitric acid yielded mixtures of the corresponding o-(31, 32, and 28%, respectively), m- (21, 23, and 3%, respectively), and p-nitro (48, 45, and 69%, respectively) products (84AP695). 

Active methylene compounds also displace the nitro group at the furazan ring. Thus, 3,4-dinitrofurazan reacted with the sodium salt of ethyl (3-oxo propionate or related compounds in the presence of a crown ether to give the corresponding ester, which was readily hydrolyzed and decarboxylated (92UP1) (Scheme 146). 

Benzofurazan (benz-1,2,5-oxadiazole) reacted with bromine by addition to give a4,5,6,7-tetrabromo adduct. Bromine in hydrobromic acid solution 4-brominated both 5-methyl- and 5-bromo-benzofurazans (74JHC8I3). When 4,7-dinitrobenzofurazan was treated with ammonium chloride in refluxing acetic acid, nucleophilic displacement gave rise to the 4-chloro-7-nitro derivative (83URP1004375). Naphtho[l, 2-c]furazans (42) are mainly 4-halogenated, but there is minor substitution in the 8-position (73CHE1331). 

This oxygen rich explosive is claimed to be the first pemitro heterocycle known. See other furazan /v-oxidks, c-nitro compounds... 

The amino- and nitro-substituted furazans and furoxans have been studied in detail because they are useful precursors for the synthesis of new derivatives and, moreover, they can be used as starting materials for the preparation of new heterocyclic systems. 

A series of hydroxy-, alkoxy-, and phenoxyfurazans and difurazanyl ether derivatives 184 were synthesized by reactions of mono- and dinitrofurazans 183 with O-nucleophiles. The effect of the furazan nature and reactant ratio on the structure of products has been discussed <1999RJ01525>. In this way, the nitro group has been replaced by alkoxy derivatives (Equation 33) <2000BMC1727>. 

Adjacent 2-azido and 3-nitro groups facilitate the elimination of nitrogen followed by ring closure to form the corresponding furazan iV-oxide compound 342 (Equation 77) <1996JOC5801, 2005AGE7089>. 

Nitro and amino derivatives of the furazan ring (1,2,5-oxadiazole) are nitrogen-rich energetic materials with potential use in both propellant and explosive formulations. Some... 

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