Unexpected nonplanar quinoidal substructure in an abietane terpene from Salvia candelabrum - An ab initio computational search for the simplest substitution pattern causing the nonplanarity

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

A recently isolated natural diterpene (candelabroquinone) unexpectedly displayed nonplanarity in its quinoidal substructure on using a variety quantum chemical methods for unrestricted geometry optimisation (PM3, HF 3-21G, HF 6-31G* and HF 6-31G**). By gradual structural simplification, it was possible to identify the minimum substitution pattern causing the nonplanarity. Appreciable alteration from planarity was found when the original three-ring compound was simplified to a two-ring structure containing a cyclohexene ring fused to the 1,4-benzoquinoidal substructure having an oxo substituent in the cyclohexene ring next to the anellation. A decreased but definite nonplanarity was still observed when the oxo group was replaced by a methyl group. On removing the methyl substituent the quinoidal ring became planar and it remained so even when the two-ring molecule was further simplified to a fully substituted one-ring system.

Original languageEnglish
Pages (from-to)153-155
Number of pages3
JournalJournal of Molecular Structure: THEOCHEM
Volume717
Issue number1-3
DOIs
Publication statusPublished - Mar 17 2005

Fingerprint

Abietane Diterpenes
terpenes
Salvia
Terpenes
substructures
Substitution reactions
substitutes
Molecules
Geometry
Diterpenes
rings
ring structures
simplification
cyclohexene
optimization
geometry

Keywords

  • Ab initio geometry optimisation
  • Candelabroquinone
  • Molecular modelling
  • Nonplanar quinoidal structure
  • Substitution pattern

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Computational Theory and Mathematics
  • Atomic and Molecular Physics, and Optics

Cite this

@article{327afe439a2f4c96b1bf691743c6c99c,
title = "Unexpected nonplanar quinoidal substructure in an abietane terpene from Salvia candelabrum - An ab initio computational search for the simplest substitution pattern causing the nonplanarity",
abstract = "A recently isolated natural diterpene (candelabroquinone) unexpectedly displayed nonplanarity in its quinoidal substructure on using a variety quantum chemical methods for unrestricted geometry optimisation (PM3, HF 3-21G, HF 6-31G* and HF 6-31G**). By gradual structural simplification, it was possible to identify the minimum substitution pattern causing the nonplanarity. Appreciable alteration from planarity was found when the original three-ring compound was simplified to a two-ring structure containing a cyclohexene ring fused to the 1,4-benzoquinoidal substructure having an oxo substituent in the cyclohexene ring next to the anellation. A decreased but definite nonplanarity was still observed when the oxo group was replaced by a methyl group. On removing the methyl substituent the quinoidal ring became planar and it remained so even when the two-ring molecule was further simplified to a fully substituted one-ring system.",
keywords = "Ab initio geometry optimisation, Candelabroquinone, Molecular modelling, Nonplanar quinoidal structure, Substitution pattern",
author = "I. P{\'a}link{\'o} and P. Forg{\'o}",
year = "2005",
month = "3",
day = "17",
doi = "10.1016/j.theochem.2004.10.070",
language = "English",
volume = "717",
pages = "153--155",
journal = "Computational and Theoretical Chemistry",
issn = "2210-271X",
publisher = "Elsevier BV",
number = "1-3",

}

TY - JOUR

T1 - Unexpected nonplanar quinoidal substructure in an abietane terpene from Salvia candelabrum - An ab initio computational search for the simplest substitution pattern causing the nonplanarity

AU - Pálinkó, I.

AU - Forgó, P.

PY - 2005/3/17

Y1 - 2005/3/17

N2 - A recently isolated natural diterpene (candelabroquinone) unexpectedly displayed nonplanarity in its quinoidal substructure on using a variety quantum chemical methods for unrestricted geometry optimisation (PM3, HF 3-21G, HF 6-31G* and HF 6-31G**). By gradual structural simplification, it was possible to identify the minimum substitution pattern causing the nonplanarity. Appreciable alteration from planarity was found when the original three-ring compound was simplified to a two-ring structure containing a cyclohexene ring fused to the 1,4-benzoquinoidal substructure having an oxo substituent in the cyclohexene ring next to the anellation. A decreased but definite nonplanarity was still observed when the oxo group was replaced by a methyl group. On removing the methyl substituent the quinoidal ring became planar and it remained so even when the two-ring molecule was further simplified to a fully substituted one-ring system.

AB - A recently isolated natural diterpene (candelabroquinone) unexpectedly displayed nonplanarity in its quinoidal substructure on using a variety quantum chemical methods for unrestricted geometry optimisation (PM3, HF 3-21G, HF 6-31G* and HF 6-31G**). By gradual structural simplification, it was possible to identify the minimum substitution pattern causing the nonplanarity. Appreciable alteration from planarity was found when the original three-ring compound was simplified to a two-ring structure containing a cyclohexene ring fused to the 1,4-benzoquinoidal substructure having an oxo substituent in the cyclohexene ring next to the anellation. A decreased but definite nonplanarity was still observed when the oxo group was replaced by a methyl group. On removing the methyl substituent the quinoidal ring became planar and it remained so even when the two-ring molecule was further simplified to a fully substituted one-ring system.

KW - Ab initio geometry optimisation

KW - Candelabroquinone

KW - Molecular modelling

KW - Nonplanar quinoidal structure

KW - Substitution pattern

UR - http://www.scopus.com/inward/record.url?scp=14844320823&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=14844320823&partnerID=8YFLogxK

U2 - 10.1016/j.theochem.2004.10.070

DO - 10.1016/j.theochem.2004.10.070

M3 - Article

AN - SCOPUS:14844320823

VL - 717

SP - 153

EP - 155

JO - Computational and Theoretical Chemistry

JF - Computational and Theoretical Chemistry

SN - 2210-271X

IS - 1-3

ER -