β-Amino ketoximes: a study of basicity, hydrogen bonding and isomerism

Abstract

The protonation reactions of the diamine dioxime 4,4,9,9-tetramethyl- 5,8-diazadodecane-2,11-dione dioxime and its O-methyl and bis-O-methyl ethers have been studied at 25°, I 0.10 M NaCl. The (substituted) oxime groups cause a marked reduction in the basicity of the secondary amino groups. log K (potentiometric) and ΔH (calorimetric) data are interpreted in terms of inductive effects of the oxime group and possible intramolecular hydrogen bonding, N⁺-H...N(OR)=, pK_a for methoxy-amine, NH₂OMe, has been determined (4.62±0.01, I 0.10 M NaCl, 25°).        P.m.r. spectra are assigned for β-amino ketoximes having α- methyl and α-methylene groups cis and trans to =N-OR groups. Infrared spectra are reported.