The incorporation of ornithine-[2,3-13C2] into nicotine and nornicotine established by NMR

Abstract

Abstract dl -Ornithine-[2,3- 13 C 2 ] was synthesized from acetate-[1- 13 C] and ethyl acetamidocyanoacetate-[2- 13 C]. This labelled material was mixed with dl -ornithine-[5- 14 C] and fed to Nicotiana glutinosa plants by the wick method. After 10 days the plants were harvested affording radioactive nicotine and nornicotine (0.14% and 0.051% specific incorporations, respectively). Even at these low specific incorporations an examination of their 13 C NMR spectra established the incorporation of ornithine symmetrically into the pyrrolidine rings of these alkaloids. Satellites were observable at the signals due to C-2′, 3′, 4′ and 5′ positions, arising by the presence of contiguous carbons at C-2′, 3′ and C-4′, 5′.