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Conformation Analysis of the 8‐Membered Ring of 12 H ‐Dibenzo [ d , g ] [1, 3, 2] dioxathiocines: Symmetric and Asymmetric Conformations
Author(s) -
Hug P.,
Kolly Sandra,
Meier Hansrudolf,
Pitteloud Rita,
Poppinger Dieter,
Rihs Grety,
Rist Günther
Publication year - 1990
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19900730310
Subject(s) - chemistry , cyclohexane conformation , conformational isomerism , ring (chemistry) , crystallography , stereochemistry , condensation , derivative (finance) , nuclear magnetic resonance spectroscopy , solid state , atom (system on chip) , molecule , hydrogen bond , organic chemistry , physics , computer science , financial economics , economics , thermodynamics , embedded system
The 12 H ‐dibenzo [ d , g ] dioxathiocines 2 and 4 are prepared by condensation of the corresponding bis[phenols] 1 and 3 with SOCl 2 and SCl 2 , respectively. X‐Ray analysis reveals the presence of the boat‐chair ( BC ) form as the only conformer in the solid state of the cyclic thiodioxy derivative 4a , whereas the sulfinyldioxy compound 2a exists in the asymmetric axial boat ( B ) form, i. e. with endo (axial) orientation of the exocyclic O‐atom. Conformational analysis using 1 H‐NMR spectroscopy indicates the presence of a boat form for compounds 2 , whereas compounds 4 again exist in the boat chair form. A comparison of 1 H‐NMR and thermodynamic parameters with those of the cyclic sulfinyldioxy compound 5 with an equilibrium between e‐ BC and a‐ BC form (i.e. BC form with equatorial and axial orientation of the exocyclic O‐atom) is made.