A Comparison of the Reactivity and Mutagenicity of N-(Benzoyloxy)-N-(benzyloxy)benzamides
摘要:
A new series of N-(acyloxy)-N-alkoxybenzamides, N-(benzoyloxy) -N-(benzyloxy)benzamides 7 have been synthesized and have been found to be direct acting mutagens in Salmonella TA100. They undergo A(Al)1 solvolysis to give N-benzoyl-N-(benzyloxy)nitrenium ions 3 under conditions of acid catalysis as well as unusual B(Al)2 reactions at nitrogen with hydroxide. The latter process affords as intermediates the anomeric hydroxamic esters 4 which rearrange intramolecularly to esters in a HERON reaction. Rates of acid-catalyzed solvolysis and reaction with hydroxide ions correlate with Hammett a values with low sensitivity (rho = +0.32 and +0.55, respectively) in accordance with the A(Al)1 and B(Al)2 mechanisms. Mutagenicity for the series also appears to correlate with Hammett sigma values but with low, negative sensitivity (rho = -0.57), and their biological activity may be attributable to their stability under conditions of the Ames assay and hydrophobic binding to DNA, rather than their chemical reactivity.
A Comparison of the Reactivity and Mutagenicity of N-(Benzoyloxy)-N-(benzyloxy)benzamides
摘要:
A new series of N-(acyloxy)-N-alkoxybenzamides, N-(benzoyloxy) -N-(benzyloxy)benzamides 7 have been synthesized and have been found to be direct acting mutagens in Salmonella TA100. They undergo A(Al)1 solvolysis to give N-benzoyl-N-(benzyloxy)nitrenium ions 3 under conditions of acid catalysis as well as unusual B(Al)2 reactions at nitrogen with hydroxide. The latter process affords as intermediates the anomeric hydroxamic esters 4 which rearrange intramolecularly to esters in a HERON reaction. Rates of acid-catalyzed solvolysis and reaction with hydroxide ions correlate with Hammett a values with low sensitivity (rho = +0.32 and +0.55, respectively) in accordance with the A(Al)1 and B(Al)2 mechanisms. Mutagenicity for the series also appears to correlate with Hammett sigma values but with low, negative sensitivity (rho = -0.57), and their biological activity may be attributable to their stability under conditions of the Ames assay and hydrophobic binding to DNA, rather than their chemical reactivity.
Solvolysis and mutagenesis of n-acetoxy-n-alkoxybenzamides — evidence for nitrenium ion formation
作者:John J. Campbell、Stephen A. Glover、Colleen A. Rowbottom
DOI:10.1016/s0040-4039(00)98076-6
日期:——
Mutagenic N-acetoxy-N-butoxybenzamides undergo acid catalysed solvolysis in acetonitrile/water. Kinetic data and a Hammett σ+ correlation (ϱ=−1.4) indicate nitrenium ionformation in the rate determining step. Levels of mutagenicity mirror the rates of solvolysis suggesting nitrenium ion involvement.