Rapid Protium–Deuterium Exchange of 4-Aminopyridines in Neutral D2O under Microwave Irradiation

4-Aminopyridines undergo surprisingly rapid and highly-selective H/D exchange at C-2 and C-6 in neutral D2O upon microwave irradiation at only 190 °C for 2 h in a sealed vessel. This method contrasts and complements acid-mediated H/D exchange, requires no catalyst and is appropriate for the synthesis of deuterium isotop-ologues of N- and C-substituted 4-aminopyridines and a ben-zofused (quinoline) analogue.