Synthesis and thermal decomposition of N,N-dialkoxyamides

N,N-dialkoxyamides 1c, a virtually unstudied member of the new class of anomeric amides, amides bearing two electronegative atoms at nitrogen, have been synthesised in useful yields directly from hydroxamic esters using phenyliodine(III)bis(trifluoroacetate) (PIFA). Infrared carbonyl stretch frequen...

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Bibliographic Details
Published in:Organic & biomolecular chemistry 2011-06, Vol.9 (11), p.4116-4126
Main Authors: Digianantonio, Katherine M, Glover, Stephen A, Johns, Jennifer P, Rosser, Adam A
Format: Article
Language:English
Subjects:
Amides - chemical synthesis
Amides - chemistry
Free Radicals - chemistry
Magnetic Resonance Spectroscopy
Molecular Structure
Stereoisomerism
Temperature
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Summary:N,N-dialkoxyamides 1c, a virtually unstudied member of the new class of anomeric amides, amides bearing two electronegative atoms at nitrogen, have been synthesised in useful yields directly from hydroxamic esters using phenyliodine(III)bis(trifluoroacetate) (PIFA). Infrared carbonyl stretch frequencies and carbonyl (13)C NMR properties have been reported, which support strong inhibition of amide resonance in these amides. Their thermal decomposition reactions in mesitylene at 155 °C proceed by homolysis to form alkoxyamidyl and alkoxyl free radicals in preference to HERON rearrangements to esters. The reactions follow first-order kinetics and for a series of N,N-dimethoxy-4-substituted benzamides, activation energies of 125-135 kJ mol(-1) have been determined together with weakly negative entropies of activation.
ISSN:1477-0520
1477-0539
DOI:10.1039/c1ob00008j