N-hydroxymethylnorcotinine, a new primary in vitro metabolite of cotinine.

1. N-Hydroxymethylnorcotinine; 5-(3'-pyridyl)-1-hydroxymethyl-pyrrolidone-2, was found as a new primary metabolite of cotinine in vitro. 2. N-Hydroxymethylnorcotinine was synthesized and characterized by gas chromatography-mass spectrometry, mass spectra, nuclear magnetic resonance and ultraviolet spectroscopy. 3. This new metabolite is formed by incubation of cotinine with hamster hepatic microsomes in the presence of NADPH and oxygen.