Diversity-Oriented Synthesis of Spiro[chromeno[2,3-b]pyridine-3,4′-pyrazole] Derivatives via Pseudo-Three-Component Reactions

Abstract

A novel one-pot pseudo-three-component reaction of 2-amino-4H-chromen-4-ones with 4-benzylidene-5-alkyl-2-aryl-2,4-dihydro-3H-pyrazol-3-ones was investigated for the synthesis of the spiro[chromeno[2,3-b]pyridine-3,4′-pyrazole] derivatives. This procedure involved Michael addition, elimination, and hetero-Diels–Alder sequences, affording a series of spiropyrazolone-chromeno[2,3-b]pyridines in good yields that possessed cis relationships between two aryl groups and the carbonyl of the pyrazolone unit.