Determination of ring inversion barriers for 1H,3H-naphtho[1,8-cd]-pyran and its methyl substituted derivatives by molecular mechanics calculations and dynamic nuclear magnetic resonance spectroscopy

Research output: Contribution to journal › Journal article › Research › peer-review

Standard

Determination of ring inversion barriers for 1H,3H-naphtho[1,8-cd]-pyran and its methyl substituted derivatives by molecular mechanics calculations and dynamic nuclear magnetic resonance spectroscopy. / Anderson, J. Edgar; Jørgensen, Flamming S.

In: Journal of the Chemical Society, Perkin Transactions 2, No. 4, 01.01.1981, p. 741-746.

Research output: Contribution to journal › Journal article › Research › peer-review

Harvard

Anderson, JE & Jørgensen, FS 1981, 'Determination of ring inversion barriers for 1H,3H-naphtho[1,8-cd]-pyran and its methyl substituted derivatives by molecular mechanics calculations and dynamic nuclear magnetic resonance spectroscopy', Journal of the Chemical Society, Perkin Transactions 2, no. 4, pp. 741-746. https://doi.org/10.1039/P29810000741

APA

Anderson, J. E., & Jørgensen, F. S. (1981). Determination of ring inversion barriers for 1H,3H-naphtho[1,8-cd]-pyran and its methyl substituted derivatives by molecular mechanics calculations and dynamic nuclear magnetic resonance spectroscopy. Journal of the Chemical Society, Perkin Transactions 2, (4), 741-746. https://doi.org/10.1039/P29810000741

Vancouver

Anderson JE, Jørgensen FS. Determination of ring inversion barriers for 1H,3H-naphtho[1,8-cd]-pyran and its methyl substituted derivatives by molecular mechanics calculations and dynamic nuclear magnetic resonance spectroscopy. Journal of the Chemical Society, Perkin Transactions 2. 1981 Jan 1;(4):741-746. https://doi.org/10.1039/P29810000741

Author

Anderson, J. Edgar ; Jørgensen, Flamming S. / Determination of ring inversion barriers for 1H,3H-naphtho[1,8-cd]-pyran and its methyl substituted derivatives by molecular mechanics calculations and dynamic nuclear magnetic resonance spectroscopy. In: Journal of the Chemical Society, Perkin Transactions 2. 1981 ; No. 4. pp. 741-746.

Bibtex

@article{f069e6ba04da45c684cbf8e0395e14bd,
title = "Determination of ring inversion barriers for 1H,3H-naphtho[1,8-cd]-pyran and its methyl substituted derivatives by molecular mechanics calculations and dynamic nuclear magnetic resonance spectroscopy",
abstract = "Molecular mechanics calculations with Allinger's MMPI program indicate that substitution of the methylene hydrogens in 1H,3H-naphtho[1,8-cd]pyran with methyl groups lowers the barrier to ring inversion. This seems to arise from increasing steric interactions in the ground state, whereas the energy of the transition state is less affected. The transition state for the inversion process has been calculated to possess C2υ, symmetry. Increased steric interactions on the introduction of methyl groups result in a more planar (i.e less puckered) ground state with an increased C-O-C bond angle. Dynamic 1H n.m.r. spectroscopy of 2,2-dimethyl-1H,3H-naphtho[1,8-cd]pyran reveals a △G† value for ring inversion of 6.9 kcal mol-1 at -133°. For the four other naphthopyrans studied by dynamic n.m.r. only upper limits for the inversion barrier are obtained.",
author = "Anderson, {J. Edgar} and J{\o}rgensen, {Flamming S.}",
year = "1981",
month = jan,
day = "1",
doi = "10.1039/P29810000741",
language = "English",
pages = "741--746",
journal = "Royal Chemical Society. Journal. Perkin Transactions 2",
issn = "1472-779X",
publisher = "Royal Society of Chemistry",
number = "4",

}

RIS

TY - JOUR

T1 - Determination of ring inversion barriers for 1H,3H-naphtho[1,8-cd]-pyran and its methyl substituted derivatives by molecular mechanics calculations and dynamic nuclear magnetic resonance spectroscopy

AU - Anderson, J. Edgar

AU - Jørgensen, Flamming S.

PY - 1981/1/1

Y1 - 1981/1/1

N2 - Molecular mechanics calculations with Allinger's MMPI program indicate that substitution of the methylene hydrogens in 1H,3H-naphtho[1,8-cd]pyran with methyl groups lowers the barrier to ring inversion. This seems to arise from increasing steric interactions in the ground state, whereas the energy of the transition state is less affected. The transition state for the inversion process has been calculated to possess C2υ, symmetry. Increased steric interactions on the introduction of methyl groups result in a more planar (i.e less puckered) ground state with an increased C-O-C bond angle. Dynamic 1H n.m.r. spectroscopy of 2,2-dimethyl-1H,3H-naphtho[1,8-cd]pyran reveals a △G† value for ring inversion of 6.9 kcal mol-1 at -133°. For the four other naphthopyrans studied by dynamic n.m.r. only upper limits for the inversion barrier are obtained.

AB - Molecular mechanics calculations with Allinger's MMPI program indicate that substitution of the methylene hydrogens in 1H,3H-naphtho[1,8-cd]pyran with methyl groups lowers the barrier to ring inversion. This seems to arise from increasing steric interactions in the ground state, whereas the energy of the transition state is less affected. The transition state for the inversion process has been calculated to possess C2υ, symmetry. Increased steric interactions on the introduction of methyl groups result in a more planar (i.e less puckered) ground state with an increased C-O-C bond angle. Dynamic 1H n.m.r. spectroscopy of 2,2-dimethyl-1H,3H-naphtho[1,8-cd]pyran reveals a △G† value for ring inversion of 6.9 kcal mol-1 at -133°. For the four other naphthopyrans studied by dynamic n.m.r. only upper limits for the inversion barrier are obtained.

UR - http://www.scopus.com/inward/record.url?scp=37049097849&partnerID=8YFLogxK

U2 - 10.1039/P29810000741

DO - 10.1039/P29810000741

M3 - Journal article

AN - SCOPUS:37049097849

SP - 741

EP - 746

JO - Royal Chemical Society. Journal. Perkin Transactions 2

JF - Royal Chemical Society. Journal. Perkin Transactions 2

SN - 1472-779X

IS - 4

ER -

ID: 218714752