Ultrasound-assisted rapid and efficient one-pot synthesis of furanyl spirooxindolo and spiroquinoxalinopyrrolizidines by 1,3-dipolar cycloaddition: a green protocol

Efficient synthesis of novel spirooxindolo and spiroquinoxalinopyrrolizidine derivatives was expediently accomplished with regioselectivity via one-pot, three-component 1,3-dipolar cycloaddition using ultrasonication. Chalcones derived from both heteroaryl methyl ketones and furfural were used as dipolarophiles in these reactions. The synthesized compounds were analyzed by 1H and 13C nuclear magnetic resonance (NMR), mass spectrometry, and elemental (CHN) analysis. Single-crystal X-ray diffraction studies of one of the compounds (11d) proved the structure and regiochemistry of the cycloaddition. The ultrasound methodology is clearly advantageous, and the desired products were obtained in moderate to good yield in shorter reaction time compared with conventional heating and fusion methods.