Nitrogen-15 Nuclear Magnetic Resonance Spectroscopy. Natural Abundance Nitrogen-15 Spectra of the cis and trans Isomers of Secondary Alkylformamides

Abstract

The ^(15)NMR chemical shifts were measured of a number of N-substituted formamides and acetamides at the natural abundance level. The ratios of the cis and trans isomers for several N-alkylformamides were also determined. Substituent effects on the ^(15)N 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(^(15)NH)] wherein the trans isomers of N-alkylformamides are larger than those of the cis isomers.

Additional details