An eco-friendly synthesis of 2-pyrazoline derivatives catalysed by $$\hbox {CeCl}_{3} \cdot 7\hbox {H}_{2}\hbox {O}$$ CeCl 3 · 7 H 2 O

Abstract

1,3,5-triaryl-2-pyrazoline derivatives were synthesised by a condensation reaction between chalcones and phenyl hydrazine using cerium chloride heptahydrate as a catalyst. All these reactions were carried out in ethyl lactate (70%) as a green solvent. Easy and efficient work up, recyclability of solvent and catalyst are the key merits of this protocol. SYNOPSIS A facile protocol for the synthesis of 1,3,5-triaryl-2-pyrazolines is described. The solvent ethyl lactate, obtained from renewable sources, is biodegradable. The catalyst $$\hbox {CeCl}_{3} \cdot 7\hbox {H}_{2}\hbox {O}$$ is a water-tolerant Lewis acid with low toxicity. Easy and clean work up, recyclable solvent and catalyst are merits of the protocol. The reaction works well for all systems giving good yields of the desired products.