Reissert compounds. The reaction of some thiocarbonyl chlorides with quinoline, isoquinoline, and pyridine

Abstract

Certain alkyl- and aryl-oxythiocarbonyl chlorides with potassium cyanide and quinoline or isoquinoline yield Reissert compounds (1 and 2; R CS·OEt and CS·OPh). The marked deshielding influence of the thiocarbonyl over the corresponding carbonyl derivatives is noted in the n.m.r. spectra. Attempts to extend the reaction with thiophosgene were unsuccessful. Instead, o-isothiocyanato-trans-cinnamaldehyde (5) and 3-oxoimidazo[1,5,-a]quinoline (6) were obtained from quinoline, thiophosgene, and potassium cyanide. Higher yields of the aldehyde resulted on replacement of cyanide by hydroxide ion. The cis-isomer of o-isothiocyanatocinnamaldehyde (12) was obtained when barium carbonate was used as base. Similar isothiocyanato-formyl ring-fission products (13), (20), and (21) have been obtained from isoquinoline and pyridine. A di-isoquinolino-1,3,5-oxadiazine (16) was also obtained in the isoquinoline reaction.