5- Methyl-4-nitrobenzofuroxan, rearrangement

Nitro groups in the 4-position may also participate in the rearrangement. For example, 5-chloro- and 5-methyl-4-nitrobenzofuroxans rearrange to their 7-chloro- and 7-methyl-4-nitro isomers, the ease of the process being attributed to steric inhibition of resonance for the nitro group in the starting materials. Similarly, 4-ethoxycarbonylamino-5,7-dinitroben-zofuroxan equilibrates with its 4,6-dinitro-5-urethane isomer. 

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