Substituent-Oriented Synthesis of Substituted Pyrazoles/Chromeno[3,2- c]pyrazoles via Sequential Reactions of Chromones/3-Chlorochromones and Tosylhydrazones.

A facile and efficient synthetic strategy for the chemoselective synthesis of monocyclic/tricyclic-fused pyrazoles was developed, and it was oriented by different 3-position substituents (H or Cl) on the chromones. The reaction proceeded in a one-pot sequential way with a broad substrate scope and moderate to excellent yields.