Protiumdeuterium exchange of benzo-substituted heterocycles in neutral D2O at elevated temperatures

H–D exchange of 2-methylbenzofuran (1), 2-methylindole (2), 2-methylbenzimidazole (3), 2-methylbenzothiazole (4), and 2-methylbenzoxazole (5) has been studied in neutral D 2 O at elevated temperatures. While 1, 2, 3, and 4 can be specifically labelled and 4 can be perlabelled at 255 °C, 5 undergoes facile hydrolysis in D 2 O at 115 °C to 2-acetamidophenol (8) with the incorporation of deuterium into the methyl group. Keywords: H–D exchange, …