Four-component catalyst-free reaction in water: Combinatorial library synthesis of novel 2-amino-4-(5-hydroxy-3-methyl-1H-pyrazol-4-yl)-4H-chromene-3-carbonitrile derivatives

A catalyst-free combinatorial library of novel 2-amino-4-(5-hydroxy-3-methyl-1H-pyrazol-4-yl)-4H-chromene-3-carbonitrile derivatives has been developed by a four-component reaction between hydrazine hydrate (1), ethyl acetoacetate (2), 2-hydroxybenzaldehydes (3) and malononitrile (4) in water at ambient temperature.