Anuj K. Jain

Step-economic, efficient, ZnS nanoparticle-catalyzed synthesis of spirooxindole derivatives in aqueous medium viaKnoevenagel condensation followed by Michael addition

An environmentally friendly, one-pot, three-component ZnS nanoparticle-mediated synthesis of biologically important spirooxindole derivatives in water under ultrasonic irradiation is described herein. ZnS nanoparticles were synthesized by aqueous chemical method. The advantages of this method lies in its simplicity, cost effectiveness, environment friendliness, easier scaling up for large scale synthesis without using high pressure, temperature and toxic chemicals. Greenness of the process was well instituted as water was exploited both as reaction media as well as medium for synthesis of catalyst (ZnS nanoparticles). The particle size was determined by transmission electron microscopy (TEM) and XRD. Compared with other methods for synthesis of spirooxindole derivatives, satisfactory results were obtained with high yields, short reaction time, with simple experimental procedure. After reaction course, the ZnS NPs can be recycled and reused without any apparent loss of activity.

CuFe2O4 nanoparticles as a highly efficient and magnetically recoverable catalyst for the synthesis of medicinally privileged spiropyrimidine scaffolds

A highly efficient and green protocol for the synthesis of medicinally important fluorinated spiropyrimidine derivatives involving creation of six new covalent bonds has been developed using a magnetically separable and reusable heterogeneous copper ferrite nanocatalyst under mild reaction conditions. The synthesis of inverse spinel copper ferrite magnetic nanoparticles with average size of 38 nm has been achieved using combined sonochemical and co-precipitation techniques in aqueous medium from readily available inexpensive starting materials without any surfactant or capping agent. The particle size was determined by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The magnetic nature of catalyst facilitates its easy removal from the reaction medium and can be reused five times without any significant loss of its catalytic activity. Negligible leaching of Cu and Fe in consecutive cycles makes the catalyst economical and environmentally benign. The structure of final products was established by single crystal X-ray analysis and spectroscopic techniques.

NaCl as a Novel and Green Catalyst for the Synthesis of Biodynamic Spiro Heterocycles in Water Under Sonication

Abstract An efficient and novel green catalytic protocol for the synthesis of biologically important spirooxindole derivatives is developed in a one-pot, three-component approach involving substituted isatin, activated methylene reagent, and 3-methyl-1-phenyl-2-pyrazolin-5-one in water under sonication. This report describes the use of sodium chloride as a nonacidic and green catalyst for a variety of substrates. The advantageous features of this methodology are the environmentally benign character, operational simplicity, high yield processing, easy handling, and the fact that the products do not need to be purified.

Ultrasound promoted clay catalyzed efficient and one pot synthesis of substituted oxindoles

A simple facile, one-pot synthesis of oxindoles in reasonable purity is reported via intramolecular Friedal-Craft cyclization. Clay KSF is an inexpensive, efficient and mild catalyst for the synthesis of substituted oxindoles by the reaction of chloroacetyl chloride and various anilines under the influence of ultrasonic irradiation under solvent-free conditions. The remarkable advantages of this method are the simple experimental procedures, short reaction times, high yields of products, suitability for a wide variety of substituents, and the green aspects through the avoidance of toxic catalyst and solvents.

Versatility of Alternative Reaction Media: Water-Mediated Domino and Green Chemical Synthesis of Pyrimido[1,2-a]benzimidazole Under Nonconventional Conditions

Abstract A convenient and clean water-mediated synthesis of a series of 4-amino-2-aryl-1,2-dihydro pyrimido[1,2-a]benzimidazoles (4) is reported using alternative nonconventional energy sources. The products are obtained in shorter times with excellent yields (78–89%) from the multicomponent reaction of 2-aminobenzimidazole (1), malononitrile/ethylcyanoacetate (2a/b), and carbonyl compounds (3). The reaction is found to be general with respect to the cyclic and acyclic carbonyl compounds. The procedure does not involve the use of any additional reagent/catalyst, produces no waste, and represents a green synthetic protocol with high atom economy.

Synthesis and biological evaluation of highly functionalized dispiro heterocycles

A series of highly functionalized dispiro[3H-indole-3,2′-pyrrolidine-3′,3′′-piperidine]-2(1H),4′′-dione derivatives have been synthesized in good to excellent yields by one pot three-component 1,3-dipolar cycloaddition reaction of substituted isatin, sarcosine and 1-methyl-3,5-bis[(E)-arylidene]piperidin-4-one with high degree of chemo-, regio- and stereoselectivity. The structure and relative stereochemistry of cycloadducts were confirmed by single crystal X-ray diffraction as well as with the help of 1H, and 13C NMR spectroscopic techniques. All the synthesized compounds were subjected to in vitro antimicrobial activity against various bacteria and fungi using broth microdilution method and antitubercular activity was carried out against Mycobacterium tuberculosis H37Rv strain using Lowenstein–Jensen medium. Some of the compounds emerged as good antimicrobials and reasonable antituberculars compared to standard drugs.