Per-6-NH2-β-CD as Supramolecular Host and Reusable Aminocyclodextrin Promoted Solvent-Free Synthesis of 2-Amino-4H-Chromene Scaffolds at Room Temperature

Abstract

Aminocyclodextrins are homogeneous CD derivatives modified by per substitution at the primary face with amino pendant groups, and this manifests combined hydrophobic and electrostatic binding of guest molecules relative to native CDs. A green multi-component tandem strategy for solvent-free synthesizing 2-amino-4H-chromene scaffolds by Knoevenagel-Michael cyclocondensation of aryl aldehydes, malononitrile and resorcinol is reported via supramolecular host and reusable per-6-amino-β-cyclodextrin at room temperature. The isolated products were checked for its purity by TLC. The final product was characterized by 1HNMR spectrometry. This study paves the use of supramolecular host and reusable aminocyclodextrin for producing of 2-amino-4H-chromene scaffolds with use of the commercially accessible inexpensive preliminary substances, energy-effectiveness, reusable catalyst, excellent yields, operational simplicity, time-saving aspects of the reaction, easy work-up, solvent-free conditions, high atom economy, green reaction conditions thus meeting some features of sustainability and green chemistry. Also, per-6-amino-β-cyclodextrin was so stable that they were capable of being used for six consecutive times with no significant change in structure and any activity loss. These characteristics have caused this procedure to be highly beneficial in facing the environmental worries and industrial needs.