= Solution
<base (chemistry)> removes an alpha-<amide> <proton> from G, giving a <carbon> <nucleophile>. Its intramolecular attack on the nitroaryl ipso <carbon>, which currently bears the <ether> <oxygen>, forms a five-membered cyclic <Meisenheimer complex>. Count its atoms along the existing tether: alpha <carbon>, the original phenyl <carbon> bearing the side chain, its adjacent phenoxy <carbon>, <ether> <oxygen>, and attacked nitroaryl ipso <carbon>. The ortho <nitro group> again stabilizes the temporarily dearomatized <anion>.
Rearomatization now breaks the nitroaryl–O bond, leaving <phenoxide> on the original ring. <proton transfer> gives \b[$\mathrm{(2{-}HOC_6H_4){-}CH(2{-}NO_2C_6H_4){-}C(=O)N_{morph}}$]. This is a <Truce-Smiles rearrangement>: the nitroaryl group migrates from <oxygen> to <carbon>, while the original phenoxy <oxygen> stays on its original ring and becomes OH. No nitro-group migration or <amide> cleavage is needed. G and H have identical formulas; only the bond connections and a <proton> position change. <carbonate> need not produce a high equilibrium <enolate> concentration: a small population can be consumed by favourable intramolecular cyclization and rearomatization. The specified transformation alone does not establish its detailed <proton>-transfer sequence.
Back to article page
