Ultrasound promoted one-pot synthesis of 2-amino-4,8-dihydropyrano[3,2-b]pyran-3-carbonitrile scaffolds in aqueous media: A complementary ‘green chemistry’ tool to organic synthesis

A green and simple approach to assembling of 2-amino-4,8-dihydropyrano[3,2-b]pyran-3-carbonitrile scaffolds via three-component reaction of kojic acid, malononitrile, and aromatic aldehydes in aqueous media under ultrasound irradiation is described. The combinatorial synthesis was achieved for this methodology with applying ultrasound irradiation while making use of water as green solvent. In comparison to conventional methods, experimental simplicity, good functional group tolerance, excellent yields, short routine, and selectivity without the need for a transition metal or base catalyst are prominent features of this green procedure.

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► Ultrasonic-assisted catalyst-free synthesis of 2-amino-dihydropyrano[3,2-b]pyran-3-carbonitriles.
► The effect of frequency and temperature of ultrasound irradiation on the reaction was studied.
► Unique combination of ultrasound activation and water.
► Better reaction times and yields than conventional methods.
► Using ultrasound irradiation, we had no need to use transition metal or base catalyst.