Search results for "intramolecular hydrogen bonding"

showing 3 items of 3 documents

Conformational analysis of α,β-dehydropeptide models at the HF and DFT levels

2004

Abstract The Ramachandran potential energy surfaces of N-acetyl-α,β-dehydroamino acid N′-monomethylamides Ac-ΔXaa-NHMe (ΔXaa=ΔAla, (Z)-ΔPhe; 1, 2) and N-acetyl-α,β-dehydroamino acid N′,N′-dimethylamides Ac-ΔXaa-NMe2 (ΔXaa=ΔAla, (Z)-ΔPhe, (Z)-ΔAbu; 3–5) were calculated at the HF/6-31G*//HF/3-21G level. The conformers localised were fully optimised at the DFT/B3LYP/6-31+G** level and their relative stabilities were analysed in terms of both π-conjugation and internal hydrogen bonding. The Ac-ΔXaa-NMe2 molecules reveal the low-energy conformer H/F, φ=−41±4°, ψ=128±4°, which is not too easily accessible for common amino acid residues. This conformer is stabilised by the bifurcated N2–CH3 O1 int…

DehydrophenylalanineHydrogen bondStereochemistryIntermolecular forceIntramolecular hydrogen bondingPotential energy surfaceCondensed Matter PhysicsDehydroalanineBiochemistryPotential energyDimethylamideschemistry.chemical_compoundchemistryDehydroalaninePotential energy surfaceMoleculePhysical and Theoretical ChemistryConformational isomerismRamachandran plotJournal of Molecular Structure: THEOCHEM
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Crystal structure of 4-[(adamantan-1-yl)amino]­naphthalene-1,2-dione

2019

The title compound, an example of a stable 1,2-naphtho­quinone, illustrates steric buttressing of the adamantanyl group.

Steric effectscrystal structureAdamantaneintra­molecular hydrogen bondingadamantanenaphthoquinoneAdamantaneCrystal structureN— HO hydrogen bonding010402 general chemistry010403 inorganic & nuclear chemistry01 natural sciencesResearch CommunicationsCrystallcsh:ChemistryDelocalized electronchemistry.chemical_compoundNaphthoquinoneGroup (periodic table)General Materials ScienceNaphthaleneintramolecular hydrogen bondingCrystal structurenaphtho­quinone548.81 Cristalografía estructuralIntramolecular hydrogen bondingGeneral ChemistryCondensed Matter PhysicsNaphthoquinone0104 chemical sciencesCrystallographychemistrylcsh:QD1-999N—H...O hydrogen bondingN—H⋯O hydrogen bondingActa Crystallographica Section E: Crystallographic Communications
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Crystal structure of (E)-2-(tert-butyl­amino)-4-(tert-butyl­imino)­naphthalen-1(4H)-one

2018

The title compound is the first example of a naphtho­quinone imine derivative crystallizing in the 4-imine/2-amine tautomeric form having bulky tert-butyl substituents at the N atoms.

crystal structureintra­molecular hydrogen bondingIminenaphthoquinoneCrystal structure010402 general chemistry01 natural sciencesMedicinal chemistryResearch Communicationslcsh:Chemistrychemistry.chemical_compoundsymbols.namesakeGeneral Materials ScienceIntra­molecular hydrogen bondingAlkylchemistry.chemical_classificationintramolecular hydrogen bonding010405 organic chemistryHydrogen bondCrystal structurenaphtho­quinoneGeneral ChemistryCondensed Matter PhysicsTautomer0104 chemical scienceslcsh:QD1-999chemistryNaphtho­quinonesymbols540 QuímicaAmine gas treatingN—H...O hydrogen bondingvan der Waals forceDerivative (chemistry)N—H⋯O hydrogen bondingActa Crystallographica Section E: Crystallographic Communications
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