AbstractThe15NMR chemical shifts were measured of a number ofN‐substituted formamides and acetamides at the natural abundance level. The ratios of thecisandtransisomers for severalN‐alkylformamides were also determined. Substituent effects on the15N chemical shifts of formamides are compared with those of some other nitrogen‐containing compounds. There is a consistent pattern of behavior of the one bond spin–spin coupling constants [1J(15NH)] wherein thetransisomers ofN‐alkylformamides are larger than those of thec