A new one-step synthesis of pyridines under microwave-assisted conditions

Tri- or tetrasubstituted pyridines are prepared by microwave irradiation of ethyl β-aminocrotonate and various alkynones in a single synthetic step and with total control of regiochemistry. This new one-pot Bohlmann–Rahtz procedure conducted at 170°C in a self-tunable microwave synthesiser gives superior yields to similar experiments conducted using conductive-heating techniques in a sealed tube and can be carried out in the presence of a Brønsted or Lewis acid catalyst.