Lipase-mediated multicomponent synthesis of 1H-Pyrazolo[1,2-b]phthalazine-5,10-dione derivatives in a binary solvent medium.

A new method for the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives via lipase from the Aspergillus niger-catalyzed multicomponent reaction of aldehydes, malononitrile, and phthalhydrazide is reported herein for the first time. This novel method holds several advantages, including its efficiency, environmental friendliness, simple workup procedure, and good yield (70-86%). The effects of temperature, organic solvents, and water content were investigated.

β-Cyclodextrin: A Green and Efficient Supramolecular Catalyst for Organic Transformations.

β-Cyclodextrin is cyclic oligosaccharide possessing hydrophobic cavity, which binds the substrates selectively and catalyze number of organic transformations with high selectivity. It catalyzes the reaction by non-covalent supramolecular bonding with reversible formation of host-guest complexes as seen in enzymes. This account summarizes our efforts in designing a good number of important organic transformations using β-cyclodextrin and its derivatives.

An efficient synthesis of 3-indolyl-3-hydroxy oxindoles and 3,3-di(indolyl)indolin-2-ones catalyzed by sulfonated β-CD as a supramolecular catalyst in water.

Sulfonated-β-cyclodextrin (β-CD-SOH) promoted efficient and fast electrophilic substitution reaction of indoles with various isatins reflux in water is reported affording various 3-indolyl-3-hydroxy oxindoles and 3,3-di(indolyl)indolin-2-ones in good to excellent yields in short reaction time.