In water, Green and Efficient Multicomponent Synthesis of 4H-Pyran Derivatives catalyzed by LiOH·H 2 O under Ultrasound Irradiation

Abstract This research work introduce a straightforward and efficient method for synthesizing 4H-pyrans via a multi-component cyclocondensation reaction involving aromatic aldehydes, malononitrile, and ethyl acetoacetate. This environmentally friendly approach utilizes ultrasound and water as the reaction medium, enabling the production of 4H-pyrans with good yields at room temperature. Notably, commercially available LiOH·H₂O serves as a dual-activated catalyst, facilitating the formation of benzylidene intermediates and serving as a mild base for 4H-pyran production. The simplicity of the operational procedure, short reaction times, cleanliness, low cost and ready availability of LiOH·H₂O, high efficiency, and excellent yields collectively render this novel approach highly appealing for 4H-pyran synthesis.