β-Cyclodextrin Monosulphonic Acid Promoted Multicomponent Synthesis of 1,8-Dioxodecahydroacridines in Water

Sulfonated β-cyclodextrins: efficient supramolecular organocatalysts for diverse organic transformations

The present review summarizes various organic transformations carried out by using sulfonated β-cyclodextrins such as β-cyclodextrin sulfonic acid, β-cyclodextrin propyl sulfonic acid, and β-cyclodextrin butyl sulfonic acid as an efficient, supramolecular reusable catalyst under diverse reaction conditions.

Urease: a highly efficient biocatalyst for synthesis of polyhydroquinolines and polyhydroacridines from the ammonia formed in situ

Urease, a nickel-dependent enzyme, has a powerful catalytic activity to decompose urea into ammonia via hydrolysis reaction under mild condition. In the present work, urease was employed for the synthesis of two series of polyhydroquinoline and polyhydroacridine derivatives via one-pot condensation of the ammonia generated in situ from urea, aryl aldehydes, and dimedone or ethyl acetoacetate (i.e., Hantzsch-type reaction) in water under mild green condition. The valuable features of this enzymatic method are mild reaction conditions, short reaction times, wide substrate toleration, and high yield of products. The present work provides a novel enzymatic catalysis to synthesize polyhydroquinolines and polyhydroacridines and expands the application of urease in organic synthesis.

New Hydrogen-Bond-Enriched 1,3,5-Tris(2-hydroxyethyl) Isocyanurate Covalently Functionalized MCM-41: An Efficient and Recoverable Hybrid Catalyst for Convenient Synthesis of Acridinedione Derivatives

A new nano-ordered 1,3,5-tris(2-hydroxyethyl) isocyanurate-1,3-propylene covalently functionalized MCM-41 (MCM-41-Pr-THEIC) was designed and prepared at room temperature through a simple procedure. According to various microscopic, spectroscopic, or thermal methods and techniques, the correlation of the catalytic performance of the hybrid mesoporous MCM-41-Pr-THEIC to its structural characteristics was fully confirmed. The new MCM-41-Pr-THEIC organosilica nanomaterials were successfully investigated as a solid mild nanocatalyst through hydrogen-bonding activation provided by its organic moiety, for the pseudo-four-component condensation of dimedone, aldehydes, and ammonium acetate or p-toluidine to afford the corresponding acridinedione derivatives under green conditions. Furthermore, the introduced nanocatalyst could be reused at least four times with negligible loss of its activity, indicating the good stability and high activity of the new hybrid organosilica.