Simple and ecofriendly synthesis of dihydropyrimidinones (thiones), dihydropyridines,and pyridines using 3‐formylchromones as substrates assisted by a recyclable Preyssler heteropolyacid

Several dihydropyrimidinones/thiones, 1,4‐dihydropyridines, and pyridine derivatives were prepared in very good yields and purity values. The corresponding reactions were carried out by employing a bulk Preyssler heteropolyacid H₁₄[NaP₅W₂₉MoO₁₁₀] as an efficient and recyclable catalyst. The preparation of pyridine derivatives was carried out not through a usual procedure, i.e., the opening of the γ‐pyrone ring of 3‐formylchromone. In general, reactions took place in solvent‐free conditions at 80°C during short reaction times.