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Conformational characteristics of kessane studied by 600 MHz 1 H NMR and molecular mechanics
Author(s) -
Lankhorst Peter P.,
van Beek Teris A.,
Haasnoot Cornelis A. G.
Publication year - 1993
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260310613
Subject(s) - chemistry , cycloheptane , ring (chemistry) , vicinal , cyclopentane , molecular mechanics , cyclohexane conformation , coupling constant , nuclear magnetic resonance spectroscopy , computational chemistry , crystallography , stereochemistry , molecular dynamics , molecule , hydrogen bond , organic chemistry , physics , particle physics
The conformational characteristics of kessane were investigated by means of 600 MHz 1 H NMR spectroscopy and molecular mechanics (MM2) calculations. Accurate vicinal 1 H 1 H coupling constants were obtained by means of extensive computer simulations. These experimental values were compared with coupling constants calculated by the combined use of MM2 calculations and the generalized Karplus equation. It is shown that kessane adopts a single conformation in solution which is only slightly different from the conformation predicted by the MM2 calculations. The cyclopentane ring of kessane is characterized by a pure 1 E conformation. The cycloheptane ring adopts a conformation which is situated precisely between the twist‐chair TC 9 and the chair C 5 conformation on the pseudo‐rotational pathway of the seven‐membered ring.