Studies on nitroaromatic compounds. Part VII. A nuclear magnetic resonance study of the reaction of [2H3]methoxide ion with some polynitrodimethylnaphthalenes

Abstract

The interaction of 1, 8-dimethyl-2, 4, 5,7-tetranitro-(I), 1, 5-dimethyl-2, 4, 6, 8-tetranitro-(II), and 1, 5-dimethyl-2, 4, 8-trinitro-naphthalene (III) with [²H₃]methoxide ion in [²H₆]dimethyl sulphoxide has been investigated by ¹H n.m.r. spectroscopy. The major initial reaction is proton abstraction from a methyl group of (I)–(III) to give a resonance stabilised benzyl-type anion. The anions from (I) and (III) are stable, whereas the anion from (II) undergoes isomerisation to give a stable product. The anion from (III), unlike those from (I) and (II), can react with [²H₃]methoxide ion to give a dianionic species. In the case of (I), addition of base to a nuclear position in the parent nitro-compound competes with proton abstraction.