¹³C N.M.R spectra of quinoline and methylquinolines. The magnitude of the vicinal (peri) ³J_CCCH coupling constants

Abstract

The ¹³C chemical shifts and the ¹³C-¹H coupling constants of quinoline, isoquinoline and five methylquinolines are reported. A vicinal (peri) ³J_CCCH coupling constant of approximately 5 Hz is observed between both C5-H4 and C4-H5. The α-, meta- and para-methyl substituent shifts are similar in magnitude to those observed for methylbenzenes and methylpyridines but the ortho-shifts vary in both sign and magnitude.