Original scientific paper

1H- and 13C-NMR Study of Naphtho[2,1-b]thiophene and Naphtho[2,1-b]furan Derivatives

Miroslav Bajić ; Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, 41000 Zagreb, Croatia
Grace M. Karminski-Zamola ; Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, 41000 Zagreb, Croatia
Branimir Klaić ; Tracer Laboratory, Department of Organic Chemistry and Biochemistry, Ruder Bošković Institute, P. O. Box 1016, 41001 Zagreb, Croati

Abstract

A series of four substituted naphtho[2,l-b]thiophenes 1-4 and a series of five substituted naphtho[2,l-b] furans 5-9 have been studied using one- and two-dimensional 1H- and 13C-NMR methods. Chemical shifts of protons could not be assigned on the basis of the homonuclear correlation (COSY) spectra only, but two-dimensional nuclear Overhauser (NOESY) spectroscopy had to be used. The cross-peak between HI and H9 enabled unequivocal assignation of the H6-H9 four proton spin system. On the bases of NOE measurements of the naphtho[2,l-b]thiophene 3, it was possible to estimate the interatom distances between HI and H9 protons of 209 pm, and between HI and H2 of 244 pm, respectively. Chemical shifts of substituted carbons were assigned using two-dimensional 1H/13C heteronuclear correlation (HET- COR) spectra. The substitution effect and the effect of solvent on the chemical shifts of the furan and thiophene analogues are reported, and the coupling constants VH H were determined.

Keywords

Hrčak ID:

136886

URI

https://hrcak.srce.hr/136886

Publication date:

1.8.1994.

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