Das Aminofurazan (Ia) bzw. das Aminofuroxan (Ib) werden mit CF3‐CO3H zu den Nitro‐Derivaten (IIa) bzw. (IIb) oxidiert; unter analogen Bedingungen liefert das (Ib)‐Isomere (III) überwiegend das Nitrofurazan (IIa) und nur in geringer Menge das gewünschte Furoxan (IV).

The structure of two isomeric chloro(phenyl)furoxans is proposed by comparison of their 13C nmr spectra with those of several unsymmetrically substituted furoxans and related furazans.

From 3‐methyl‐4‐furoxancarboxylic acid hydrazide and 4‐methyl‐3‐furoxancarboxylic acid hydrazide the corresponding azides have been synthesized. 3‐Methyi‐4‐furoxancarboxylic acid azide normally underwent the Curtius reaction to give the expected carbamic acid derivative. The degradation of 4‐methyl‐3‐furoxancarboxylic acid azide led to the N‐(4‐methylfuroxan‐3‐yl)‐carbamic acid derivative at low temperatures and to N‐(3‐methylfuroxan‐4‐yl)carbamic acid derivative at higher temperatures.

No abstract

From the mixture of isomeric esters obtained by heating 3‐methy 1‐4‐furoxancarboxylie acid ethyl ester, some furoxan derivatives have been prepared; their structures were assigned on the basis of nmr spectroscopy.