The effect of DMSO on the basic methanolysis of benzanilides

Broxton, Trevor J.; Deady, Leslie W.; Pang, Yan

doi:10.1016/s0040-4039(00)75243-9

Cited by 3 publications

(2 citation statements)

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“…Amidic resonance is one of the most fundamental effects in organic chemistry that has been extensively utilized to control conformation and reactivity of atoms comprising the amide linkage. − The hindered barrier to rotation around the N–C(O) bond determines the overall structure of molecules featuring amides. , This effect has been utilized in molecular recognition, conformational relays, and drug–receptor interactions. − Amidic resonance in simple N -acylanilines (anilides) has long been recognized as a key feature controlling cis–trans conformational preference of the amide bond …”

Section: Introductionmentioning

confidence: 99%

Resonance Destabilization in N-Acylanilines (Anilides): Electronically-Activated Planar Amides of Relevance in N–C(O) Cross-Coupling

2017

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Transition-metal-catalyzed activation of amide N-C(O) bonds proceeds via selective metal insertion into the carbon-nitrogen amide bond. Herein, we demonstrate that N-acylanilines (anilides), the first class of planar amides that have been shown to undergo selective amide N-C cross-coupling reactions, feature a significantly decreased barrier to rotation around the amide N-C(O) bond. Most significantly, we demonstrate that amide n → π* resonance in simple anilides can be varied by as much as 10 kcal/mol. The data have important implications for the design of N-C(O) amide cross-coupling reactions and control of the molecular conformation of anilides by resonance effects.

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Section: Introductionmentioning

confidence: 99%

Resonance Destabilization in N-Acylanilines (Anilides): Electronically-Activated Planar Amides of Relevance in N–C(O) Cross-Coupling

2017

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“…The mechanism or combination of mechanisms that applies in a given series depends upon the identity of R (H or methyl),1 23the nature of R' (methyl, trifluoromethyl, or aryl),2,6 and the solvent (methanol or Me2SOmethanol).4 56Of particular interest here is the possible occurrence of mechanism C. In methanol as solvent it has been suggested that mechanism C applies only for tertiary amides (R = methyl) in which the aromatic ring contains a nitro group at the para position, as a result of the combination of both steric and electronic effects.1 In 80% Me2SO-methanol the occurrence of mechanism C is more common, and it has been reported for iV-aryl-N-methylbenzamides which contain substituents of equal or greater electron-withdrawing power than p-bromo. 4 The wider occurrence of mechanism C in 80% Me2SO-methanol has been explained by the dramatic increase in basicity of methoxide ion on transfer from methanol to 80% Me2SO-methanol (greater than 4 pKa units)7 and the expected much smaller increase, if any, in basicity of the larger amine anions.8 This results in a large decrease in and a smaller decrease in k2 (i.e., k2/k^i increases). The occurrence of mechanism C should also be favored by a decrease in the basicity of the amine leaving group, and for this reason we have now looked at the basic methanolysis of a series of substituted N-aryl-iV-phenylbenzamides (II).…”

Section: Methodsmentioning

confidence: 99%