Protiumdeuterium exchange of substituted pyridines in neutral D2O at elevated temperatures

H–D exchange of a series of pyridines 1–15, 10H-pyridino[3,2-b][1,4]benzothiazine (16), phenothiazine (17), and aniline has been carried out in neutral D 2 O at elevated temperatures. The substrates undergo selective exchange and are generally isolated in good yield. Cyanopyridines 4,5, and 6 hydrolyze readily in D 2 O at elevated temperatures, and the resultant carboxylic acids decarboxylate. This reaction provides a convenient one-step route …