An Efficient One‐Pot Synthesis of Substituted 1 H ‐Naphtho[2,1‐ b ]pyrans and 4 H ‐1‐Benzopyrans (=Chromenes) under Solvent‐Free Microwave‐Irradiation Conditions

A facile heterogeneous synthesis of 3‐amino‐1‐aryl‐1 H ‐naphtho[2,1‐ b ]pyran and 2‐amino‐4‐aryl‐4 H ‐1‐benzopyran derivatives 3 and 5 , respectively, was carried out efficiently by one‐pot three‐component coupling of an aromatic aldehyde 1 , an active methylene compound 2 , and naphthalen‐2‐ol or a phenol 4 in the presence of 5‐Å molecular sieves under solvent‐free microwave‐irradiation conditions ( Scheme 1 and 2, Tables 1 and 2 ). The catalyst was recovered and recycled ( Table 3 ).