β-Cyclodextrin: A Biomimetic Catalyst used for the Synthesis of 4H-chromene-3-carbonitrile and Tetrahydro-1H-xanthen-1-one Derivatives

β-Cyclodextrin as an Efficient and Recyclable Supramolecular Catalyst for the Synthesis of Heterocyclic Compounds

“…They are found in many natural products, pharmaceutical agents, and functionalized materials . Rai and associates discussed a simple, metal‐free, and green method for the synthesis of xanthen‐1‐one 73 and 4 H ‐chromene‐3‐carbonitrile derivatives 74 via a three‐component, one‐pot reaction of salicyladehyde 70 , malononitrile 49 or dimedone 57, and indole 20 using β‐CD as an efficient and biomimetic catalyst in aqueous medium (Scheme ) . To optimize the reaction conditions, the authors studied the effect of various bases and solvents on this reaction; however, the best results were obtained using DABCO as base and water as a solvent at 60°C temperature within 40–60 min for this reaction.…”

ZnO nanoparticle–β-cyclodextrin: a recyclable heterogeneous catalyst for the synthesis of 3-aryl-4H-benzo[1,4]thiazin-2-amine in water

“…It is the best option because under aqueous conditions organic reagents which are not soluble in water are inserted into the cavity of b-cyclodextrin and form a water-soluble inclusion complex. Although surfactants were also efficient phase transfer catalysts and could be a good choice for this purpose, we discarded them because they are toxic to marine organisms and very difficult to remove from the reaction mixture 31 (Table 2, entries 4 and 5). Fortunately, the result substantiates our hypothesis and the reaction carried out in the presence of b-cyclodextrin (1 mol%) along with ZnO-NP in water would not only be faster but would also result in higher yields as compared to the previous results (Table 2, entry 1).…”

An atomistic view on the uptake of aromatic compounds by cyclodextrin immobilized on mesoporous silica

“…Their hydrophilic outer surface renders them soluble in water, while the hydrophobic interior can accommodate hydrophobic compounds. Therefore, they are employed in the removal of pollutants from aqueous media [1,2], as chiral selectors [3] or in (asymmetric) supramolecular catalysis [4][5][6][7][8][9][10] among many other fields of applications including the use of cyclodextrins as drug delivery agents or as building blocks in the design of dynamic and adaptive materials [11,12]. By tuning the size and shape of the hydrophobic cavity through derivatization of the native cyclodextrins the selectivity towards the target compounds can be increased [13].…”