Room-temperature synthesis of pyrazoles, diazepines, β-enaminones, and β-enamino esters using silica-supported sulfuric acid as a reusable catalyst under solvent- …
Abstract Silica-supported sulfuric acid (H2SO4· SiO2) has been utilized as a heterogeneous recyclable catalyst for a highly efficient regio-and chemoselective condensation of hydrazines/hydrazides, diamines, and primary amines with various β-dicarbonyl compounds at room temperature to afford pyrazoles, diazepines, and β-enaminones/β-enamino esters under solvent-free conditions within 5–15 min.