The nuclear magnetic resonance spectra of pyrrole and [N-D]pyrrole

Abstract

The proton magnetic resonance spectrum at 60 MHz of pyrrole, spin- decoupled from ¹⁴N, has been studied under high resolution. Similar studies have been made on [N-D]pyrrole in which the proton spectrum was obtained simultaneously spin-decoupled from both the ¹⁴K and ²H nuclei. Analysis of the ¹³C-H spectra of pyrrole and [N-D]pyrrole, observed in natural abundance, gave values for all six proton-proton spin-spin couplings. Values for some of the couplings have been obtained directly and unambiguously from the spectra of samples of [S-H]pyrrole and [N- D]pyrrole in which the C-H protons have been predominantly exchanged for deuterium. The values for the couplings derived are J_1,2 2.60, J_1,3 2.45, J_2,3 2.69, J_2,4 1.44, J_2,5 1.87, and J_3,4 3.34 Hz.