Efficient Domino Strategy for the Synthesis of Polyfunctionalized Benzofuran-4(5<i>H</i>)‑ones and Cinnoline-4-carboxamides

An efficient, three-component strategy for the improved synthesis of multifunctionalized 6,7-dihydrobenzofuran-4­(5H)-ones under microwave irradiation in ethyl alcohol within short periods has been established. The synthesized benzofuran-4­(5H)-ones have been readily converted into polyfunctionalized cinnoline-4-carboxamides by treating with hydrazine hydratein in the same solvent through a regioselective ring-opening of the furan. Tedious workup procedures can be avoided because of the direct precipitation of products from the reaction solution by water addition, thus rendering the two-steps process ecofriendly.