<jats:title>Abstract</jats:title> <jats:p> From the culture medium of Pseudomonas putida after treatment with CH<jats:sub>2</jats:sub>N<jats:sub>2</jats:sub> besides the expected Pyridine-2,6-di(monothiocarboxylic acid)-di-S-methyl ester a series of pyridine derivatives could be isolated which could be shown to be artefacts formed from pyridine-2,6-di(monothiocarboxylic acid).