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Furazan, 3,4-dimethyl

The thermal or photolytic fragmentation of furazans to nitriles and nitrile Af-oxides has been reported (73JOC1054, 75JOC2880). The irradiation of dimethylfurazan (419) in the presence of cyclopentene, and benzofurazan (420) in the presence of dimethyl acety-lenedicarboxylate, gave isoxazoline (421) and isoxazole (422), respectively, in good yields. The thermolysis of acenaphtho[l,2-c]furazan (423) in the presence of phenylacetylene gave isoxazole (424) in 55% yield. [Pg.81]

Isoxazole, 3-acetyl-4-chloro-5-methyl-oxidation, 6, 27, 53 Isoxazole, 3-acetyl-4,5-dimethyl-oxidation, 6, 27, 53 Isoxazole, 5-acetyl-3-methoxy-reactions, 6, 53 Isoxazole, 3-acyl-furazans from, 6, 417 nucleophilic attack, S, 93 reactions with bases, 6, 30... [Pg.685]

Because of the difficulties encountered in preparing starting materials, further data on the synthesis of these compounds are rare. Exceptionally, 3,4-dimethyl-furazan [630S(1V)342] and 3,4-dimethylfuroxan (1890CB3490, 80URP721430) were synthesized in a straightforward manner from commercially available dimethylgly oxime. [Pg.77]

The products of the reactions of picryl chloride with isomeric 4- and 5-aminobenzofurazans in dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) were studied by means of nonaqueous potentiometric titration. The effect of the position of the furazan fragment in 4- and 5-picrylaminobenzofurazans on the NH acidity is considered. The electron-acceptor properties of the furazan fragment were evaluated via inclusion of the resulting data into the pK -cr correlation for 2,4,6-trinitrodiphenylamines <2005RJC933>. [Pg.326]

The furazan ring can be constructed by the one-pot reaction of iV-(5,5-dimethyl-3-oxocyclohexenyl)-.S,.S-diphenyl-sulfilimine 272 with isopentyl nitrite <2006SC2087> and also by a one-pot procedure from sulfinimines 273, without isolation of the nitroso intermediates, in refluxing toluene (Scheme 71) <2002T10073>. [Pg.370]

Benzofurazans are thermally more stable but can be cleaved photolytically. For example, benzo-furazan itself in benzene affords cyanoisocyanate (17) and azepine (18), the latter being formed by reaction of the solvent with the putative intermediate acylnitrene (19) (Scheme 5) further supporting evidence for the proposed pathway is provided by trapping the nitrile oxide precursor with dimethyl acetylenedicarboxylate and isolation of the methylurethane derivative of the isocyanate <75JOC2880>. Photolysis of diphenylfurazan yields benzonitrile, diphenylfuroxan and 3,5-diphenyl-1,2,4-oxadiazole. [Pg.236]

Auf analogem Wege wird 3,4-Dimethyl-furazan (60-64%) erhalten77. [Pg.656]

Bei katalytischer Reduktion tritt dagegen Ringspaltung der Furazan-Ringe ein (s.S.684). Amino-furazane reagieren nicht mit typischen Alkylierungsmitteln wie Methyliodid, Dimethyl-sulfat, co-Brom-acetophenon oder Chlor-triphenyl-methan235,24°. [Pg.671]

Dimethyl-furazan laBt sich mit Butyllithium in der Seitenkette lithiieren und danach weiter... [Pg.679]

Bei der Photolyse von 3,4-Dimethyl- bzw. 3,4-Diphenyl-furazan erhalt man als Primarprodukte neben Acetonitril bzw. Benzonitril Acetonitriloxid bzw. Benzonitriloxid308 209, wobei Benzonitriloxid sich unter den Photolyse-Bedingungcn zu Phenylisocyanat umlagcrt. [Pg.684]

Disubstituierte Furazane konnen bei der Reduktion mit Lithium-alanat durch hydrierende C,C-Spaltung primare Amine liefern. So erhalt man aus 3,4-Dimethyl-furazan Ethylamin (40%)310. 3,4-Diphenyl-furazan laBt sich mit Lithiumalanat nur schwierig reduzieren nach 6 h (Diethylether) werden 59% Benzylamin erhalten. Mit Phosphor/Iodwasserstoffsaure wird... [Pg.684]

Analog erhalt man aus dem alicyclischen Furazan I mit Kaliumcarbonat in DMSO zu 25% 6,6-Dimethyl-4-hydroximino-2-phenyl-4,5,6,7-tetrahydro-2H-benzoiriazol323 ... [Pg.687]

Das UV-Spektrum von 3,4-Dimethyl-furazan-2-oxidzeigt in Ethanol eine breite Bande bei 258 nm mit mittlerer Intensitat74 76, die in aprotisehen Losungsmitteln bathochrom versehoben wird75. Eine ahnliche Bande findet man bei anderen Furazan-2-oxiden77. [Pg.720]

Dimethyl-furazan-2-oxid zeigt zwei Methyl-Signale ... [Pg.720]

Die nO- und 15N-NMR-Spektren von Furazan-2-oxideu zeigen erwartungsgemaB zwei verschie-dene Typen von O-108 bzw. N-109Atomen so findet man fiir 3,4-Dimethyl-furazan-2-oxid (wei-tere Beispiele110) ... [Pg.721]

Analog wird aus 2,3-Bis-[hydroximino]-5,5-dimethyl-l-oxo-cyclohexan bei der Dehydrierung mit Trikalium-hexacyanoferrat (III) ausschlieBlich das Furazan-2-oxid Vll - das instabilere Iso-mere - gebildet, das sich beim Kochen in Petrolether (100 120°)/Toluol in das stabilere Fu-razan-2-oxid VIII umwandelt220. [Pg.725]

Auch aus 2-Nitro-oximen sind durch Dehydratisierung Furazan-2-oxide zuganglich (s. Bd. X/l, S.452, 1000 Bd. X/4, S. 156) z.B. 4,5-Dimethyl-furazan-2-oxid aus 3-Hydroximino-2-nitro-butan (Arbeitsvorschrift s. Bd.X/1, S.452) ... [Pg.726]

Die Nitrosierung von Dimethyl-(2-oxo-2-phenyl-ethyl)-sulfoniumbromid mit Salpetersaure/ Natriumnitrit liefert 3,4-Dibenzoyl-furazan-2-oxid (76%)342 ... [Pg.740]

Bei der Uinlagerung von 5,5-Dideutero-6,6-dimethyl-4-hydroximino-4,5,6,7-tetrahydro-benzofu-razan-l-oxid (XII) zum entsprechenden -3-oxid XIII tritt das isomere Furazan-2-oxid XIV nicht auf, obwohl lediglich eine Wasserstoff-Wanderung unter C,C-Doppelbindungs-Verschie-bung (XV -> XVI) zu erfolgen braucht372. [Pg.743]

Aus Dimethylsulfoxid Dimethyl-(3-nitro-2-py-ridylimino) -oxo-sulfuran369 ... [Pg.808]

Aziminobis [4-methyl] furazan (called l,3-Bis-[4-methyl-1.2.5-oxidiazolyl-(3)]-triazen or 4.4 -Dimethyl-[3 3 -diazoamino-furazan] in Ger),... [Pg.643]

Oxadiazoles are difficult to alkylate. However, N-methylfurazinium salts are formed on heating furazans with dimethyl sulfate (74AJC1917,95JCS(P1)1083) the reaction is approximately 7 and 62 times slower, respectively, than the corresponding methylations of 1,2,5-thiadiazole and isoxazole. The N-ethyl salts of furazan itself and 3-phenylfurazan have been prepared using triethyloxonium tetrafluoroborate (64JA1863). [Pg.382]


See other pages where Furazan, 3,4-dimethyl is mentioned: [Pg.25]    [Pg.50]    [Pg.40]    [Pg.25]    [Pg.21]    [Pg.57]    [Pg.56]    [Pg.25]    [Pg.25]    [Pg.54]    [Pg.636]    [Pg.636]    [Pg.636]    [Pg.636]    [Pg.25]    [Pg.69]    [Pg.50]    [Pg.236]    [Pg.237]    [Pg.248]    [Pg.652]    [Pg.653]    [Pg.679]    [Pg.681]    [Pg.730]    [Pg.767]    [Pg.806]    [Pg.40]    [Pg.91]    [Pg.25]    [Pg.80]   
See also in sourсe #XX -- [ Pg.34 , Pg.40 ]

See also in sourсe #XX -- [ Pg.34 , Pg.40 ]

See also in sourсe #XX -- [ Pg.34 , Pg.40 ]

See also in sourсe #XX -- [ Pg.34 , Pg.40 ]

See also in sourсe #XX -- [ Pg.34 , Pg.40 ]

See also in sourсe #XX -- [ Pg.34 , Pg.40 ]




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Furazanes

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