Ultrasound assisted multicomponent reactions: a green method for the synthesis of highly functionalized selenopyridines using reusable polyethylene glycol as reaction medium

A simple and benign one-pot protocol for the synthesis of 2-amino selenopyridine derivatives 4 has been developed using ultrasound assisted multicomponent reactions of aldehydes, malononitrile and benzeneselenol in polyethylene glycol (PEG-400). Under similar reaction conditions, sterically hindered o,o'-disubstituted aromatic aldehydes provide the corresponding functionalized seleno dihydropyridines 5. In this process in total four new bonds (two C-C, one C-N and one C-Se) forms in one pot.