Three-Component Site-Selective Synthesis of Highly Substituted 5H‑Chromeno-[4,3‑b]pyridines

An efficient and concise one-pot procedure was developed based on a cascade reaction of 3-formylchromones 1 and different types of 1,1-enediamines (EDAMs) 2 with different alcohols or amines 3 by a site-selective synthesis of 5H-chromeno­[4,3-b]­pyridines in an environmentally friendly solvent. This protocol is especially suitable for the efficient and rapid parallel synthesis of 5H-chromeno­[4,3-b]­pyridine compounds. It also has some advantages, such as convenience of operation, short reaction times, use of a green solvent, and ease of purification by washing the crude products with ethanol.