An AM1 calculational study of the protonation and reactions of 3,4-dihydro-2-oxo-1,4-ethanoquinoline, 3,4-dihydro-2-oxo-1,4-propanoquinoline, 3,3,4,5-tetrahydro-2-oxo-1,5-ethanobenzazepine, 3,3,4,5-tetrahydro-2-oxo-1,5-propanobenzazepine, and <i>N</i>-methyl-4-bromo-2-methylacetanilide

Brown, R. S.; Wang, Q.

doi:10.1139/v96-057

Cited by 20 publications

(15 citation statements)

References 13 publications

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“…Some insight into the question of N- vs. O-protonation has been provided by Brown and Wang (Scheme ). 59a,b Their observations are in line with our predictions of N-protonation of the 3̄.2.2 system and O-protonation of the 3̄.3.2 system. Brown is careful to note that it is not clear whether these very slow reactions are under kinetic or thermodynamic control.…”

Section: Resultssupporting

confidence: 88%

Small and Medium-Sized Bridgehead Bicyclic Lactams: A Systematic ab Initio Molecular Orbital Study

1996

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Optimized ab initio molecular orbital calculations on nine bridgehead bicyclic lactams ranging from the 2.2.2 to the 4.3.3 series indicate variations in structural properties, resonance energies, proton affinities, and core orbital ionization energies that reflect the trans-cycloalkene analogy. The smaller lactams are calculated to be N-protonated, the larger O-protonated, and the "crossover" is predicted to occur around the 3.3.1 system. On the basis of resonance energies, larger bridgehead bicyclic lactams could be considered to be hyperstable as Schleyer and co-workers define the concept for larger bridgehead alkenes. This, hyperstability should be apparent in the kinetics of the nucleophilic substitution reactions of the lactams, such as hydrolysis, but not in the thermochemistry of these reactions.

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Section: Resultssupporting

confidence: 88%

Small and Medium-Sized Bridgehead Bicyclic Lactams: A Systematic ab Initio Molecular Orbital Study

1996

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“…451 Using DFT calculations, Greenberg predicted that related bridged lactams display higher electron density at nitrogen as compared to planar amides. 70,71 Recently, Greenberg reported that protonation of the relatively undistorted 1-azabicyclo[3.3.1]nonan-2-one also proceeds at nitrogen (Scheme 122).…”

Section: Reactivity Of Bridged Lactams and Related Heterocyclesmentioning

confidence: 99%

Chemistry of Bridged Lactams and Related Heterocycles

2013

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CONTENTS 1. Introduction 5702 2. General Properties of Bridged Lactams 5703 2.1. Distortion Parameters of Bridged Lactams 5703 2.2. Bond Lengths of Bridged Lactams 5703 2.3. Spectroscopic Properties of Bridged Lactams 5703 2.4. Analogy of Bridged Lactams to Bridgehead Olefins 5704 2.5. Chemical and Biological Significance of Distorted Amides 5704 3. Synthesis of Historically Important Bridged Lactams 5704 3.1. Quinuclidone Derivatives 5704 3.2. Adamantanone Derivatives 5707 4. Synthesis of Bridged Lactams with the N−(CO) Bond on a Two-Carbon or Larger Bridge, ([m. (≥2).n] Type) 5708 4.1. Condensation Reactions Forming the N− C(O) Bond 5708 4.2. Heck Reactions 5711 4.3. Diels−Alder Reactions 5712 4.4. Carbene Insertion Reactions 5713 4.5. Reactions via Radical Intermediates 5714 4.6. Miscellaneous Examples 5714 5. Synthesis of Bridged Lactams with the N−(CO) Bond on a One-Carbon Bridge, ([m.1.n] Type) 5715 5.1. Carbene Insertion Reactions 5715 5.2. Schmidt Reactions 5716 5.3.

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“…Some examples of sterically hindered amides were reported [ 70 , 71 , 72 ] to exhibit moderately low amidicity and carbonylicity values. One representative example is 21 , where the amide functionality is sterically hindered and, hence, distorted.…”

Section: Discussionmentioning

confidence: 99%

Amide Activation in Ground and Excited States

et al. 2018

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Not all amide bonds are created equally. The purpose of the present paper is the reinterpretation of the amide group by means of two concepts: amidicity and carbonylicity. These concepts are meant to provide a new viewpoint in defining the stability and reactivity of amides. With the help of simple quantum-chemical calculations, practicing chemists can easily predict the outcome of a desired process. The main benefit of the concepts is their simplicity. They provide intuitive, but quasi-thermodynamic data, making them a practical rule of thumb for routine use. In the current paper we demonstrate the performance of our methods to describe the chemical character of an amide bond strength and the way of its activation methods. Examples include transamidation, acyl transfer and amide reductions. Also, the method is highly capable for simple interpretation of mechanisms for biological processes, such as protein splicing and drug mechanisms. Finally, we demonstrate how these methods can provide information about photo-activation of amides, through the examples of two caged neurotransmitter derivatives.

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An AM1 calculational study of the protonation and reactions of 3,4-dihydro-2-oxo-1,4-ethanoquinoline, 3,4-dihydro-2-oxo-1,4-propanoquinoline, 3,3,4,5-tetrahydro-2-oxo-1,5-ethanobenzazepine, 3,3,4,5-tetrahydro-2-oxo-1,5-propanobenzazepine, and N-methyl-4-bromo-2-methylacetanilide

Cited by 20 publications

References 13 publications

Small and Medium-Sized Bridgehead Bicyclic Lactams: A Systematic ab Initio Molecular Orbital Study

Small and Medium-Sized Bridgehead Bicyclic Lactams: A Systematic ab Initio Molecular Orbital Study

Chemistry of Bridged Lactams and Related Heterocycles

Amide Activation in Ground and Excited States

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