The nitration of 2,4-dibromo-3,5,6-trimethylphenol and some reactions of polysubstituted phenols with nitrogen dioxide; X-ray crystal structure of 4-Acetyl-1-bromo-r-3,c-4-epoxy-2,t-5-dimethyl-3,5-dinitrocyclopentene

Abstract

Nitrations of phenols (3a), (3b), (7) and (8) with nitrogen dioxide in cyclohexane give similar patterns of reaction to those with fuming nitric acid in acetic acid. Nitration of 2,4-dibromo-3,5,6-trimethyl- phenol (19) with nitrogen dioxide gives isomeric trinitrocyclohex-3-enones (24), while fuming nitric acid reactions yield either the trinitro ketone (24a) and the cis-dinitro ketone (25) or the C2-epimeric ketones (25) and (26) depending upon the reaction conditions. Some reactions of these products are described, and the X-ray crystal structure of the epoxycyclopentene derivative (30) is reported.