Carbon-13 Nuclear Magnetic Resonance Spectra of Isothiazole, 1,2-Dithiole, and 1,3-Dithiole Derivatives

Abstract

Carbon-13 chemical shift data have been obtained for a number of isothiazole, benzo[c]isothiazole, 1,2-dithiole, and 1,3-dithiole derivatives. A number of these compounds are thiones and the chemical shifts of the C=S carbons are discussed in the light of recent attempts to predict such chemical shifts from those of the analogous carbonyl compounds. Comparisons of substituent chemical shift (s.c.s.) effects in these heterocyclic compounds with those in simpler aromatic or conjugated systems have been made and additivity correlations tested in a number of cases.

Carbon-13 nuclear magnetic resonance spectra of organic sulfur compounds. Substituent chemical shift (s.c.s.) effects in the 4-thiazoline-2-thione series

“…The position of the thione carbon signal in 1 (188.4 ppm), although at relatively high field for a C=S functionality, is very similar to the values of 186.7 and 187.3 pprn which we reported for two 4-isothiazoline-3-thione, 4, derivatives (6). In part, this must be attributed to the effect of the adjacent N-atom with its electron-releasing capability (sulfur having a much smaller effect).…”

A Comment on the Paper “Benzo-lλ4, 2-thiazol, a New Bicyclic 10π-System”

“…The iH and 13 C NMR data reported in the paper [1] are identical with those reported earlier for 2,1-benzisothiazoles [3,4], showing clearly that the compound is 5,7-dimethyl-2,l-benzisothiazole.…”

Carbon-13 nuclear magnetic resonance spectra of organic sulfur compounds. Comparison of chemical shifts for carbonyl and thiocarbonyl compounds in the pyrone, thiopyrone, and pyridone series

“…The extensive collection of chemical shifts for the carbonyl and thiocar bony1 derivatives in these series of compounds has been used to Can (9) and later discussed in our previous paper on this subject (10).…”