Collect. Czech. Chem. Commun. 1993, 58, 113-120

NMR Spectroscopic Studies of Thialene (Cyclopenta[b]thiapyran) and Isothialene (Cyclopenta[c]thiapyran)

Robert F. X. Kleina, Václav Horáka and Arthur G. Anderson, Jr.b

a Department of Chemistry, Georgetown University Washington, DC 20057-0001, U.S.A.
b Department of Chemistry, University of Washington, Seattle, Washington 98195-0001, U.S.A


1H and 13C NMR spectral parameters are reported for the S-pseudoazulenes thialene (cyclopenta[b]thiapyran) (I) and isothialene (cyclopenta[c]thiapyran) (II). Both compounds display complex first order spectra, with thialene having 10 and isothialene 14 of 15 possible coupling constants. Complete unambiguous assignments of all protons and non-quaternary carbons were made via 2-dimensional NMR techniques and PPP-SCF π-electron density/chemical shift and π-bond order/vicinal coupling constant correlations.