Hydrolysis Reactions of N-Sulfonatooxy-N-acetyl-1-aminonaphthalene and N-Sulfonatooxy-N-acetyl-2-aminonaphthalene: Limited Correlation of Nitrenium Ion Azide/Solvent Selectivities with Mutagenicities of the Corresponding Amines

Abstract

The hydrolysis reactions of the title compounds N-sulfonatooxy-N-acetyl-1-aminonaphthalene, 2d, and N-sulfonatooxy-N-acetyl-2-aminonaphthalene, 2e, in 5% CH3CN−H2O (20 °C, pH 5.7−7.5, μ = 0.5) appear to involve nitrenium ion intermediates that exhibit very small azide/solvent trapping efficiencies. The azide/solvent selectivities, S, were estimated from fitting azide- and solvent-derived product yields as a function of [N3-]. The derived values of S for the N-acetyl-N-(1-naphthyl)nitrenium ion (3d) of 0.7 ± 0.1 M-1 and the N-acetyl-N-(2-naphthyl)nitrenium ion (3e) of 1.5 ± 0.2 M-1 show that these ions have short lifetimes (ca. 10-10 s) in aqueous solution. In turn, these results suggest that the hydrolysis reactions of 2d and 2e should proceed, in part, through ion-pair and/or preassociation pathways. The decrease in the yield of the rearrangement products N-acetyl-1-amino-2-sulfonatooxynaphthalene, 6, and N-acetyl-2-amino-1-sulfonatooxynaphthalene, 11, with increasing [N3-] indicates that this is the cas...