Asish R Das

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An ecofriendly, one-pot, three component ZnO nanoparticles-mediated synthesis of 4H-chromene in water under thermal condition has been described. The highly product-selective three component electrophilic reaction of 2-hydroxybenzaldehyde with an active methylene compound and another carbon-based varied nature of nucleophile has been developed by a(More)
Nineteen new conjugated compounds were successfully synthesized by a one-flask method from benzimidazole and coumarin derivatives. A methylenethio linker was used to connect these two kinds of derivatives. In addition, substituted benzimidazol-2-thiones were also coupled with beta-D-glucose peracetate; the resultant glucosides were further converted to the(More)
A catalyst-free green methodology for the synthesis of pharmacologically important spirooxindole derivatives has been developed by a three-component domino reaction between isatin, various amino compounds, and 1,3-dicarbonyl or 3-phenylisoxazolone compounds in ethyl l-lactate medium at room temperature. This new efficient synthetic method facilitated the(More)
A one-flask thioetherification of pyrazolones has been demonstrated by transforming several pyrazolones to their corresponding 4-mercaptopyrazolone derivatives and employing them towards cross-coupling with various aromatic and heteroaromatic iodides by applying Pd(OAc)2/xantphos as the catalytic system. The coupling ability of these thiol intermediates(More)
An advanced protocol for the diastereoselective intramolecular aziridination reaction has been developed to synthesize 2-oxa-7-azabicyclo[4.1.0]hept-3-en-1-yl carboxylates from their corresponding 4-H-pyrans and spiropyrans analogues employing iodosylbenznene as the exclusive oxidant in the presence of carboxylic acid and triethylamine. High structural and(More)
A robust intramolecular cyclopropanation reaction was first performed on pyranopyrazole and pyranopyrimidine-dione derivatives to obtain spirocyclopropylpyrazolones and barbiturates, using iodosylbenzene (PhIO) or the combination of iodobenzene diacetate (PIDA)/molecular iodine (I2), under mild reaction conditions. Syntheses of functionally and(More)
For establishment of the structure-activity relationship, 19 heterobicycle-coumarin conjugated compounds with the -SCH(2)- linker were synthesized and found to possess significant antiviral activities. Prominent examples included imidazopyridine-coumarin 12c, purine-coumarin 12d, and benzoxazole-coumarin 14c, which inhibited HCV replication at an EC(50) of(More)
Reaction of alkyl, acetoxy, and silyl enol ethers of 3-(organosilyl)cyclohexanone with molecular dioxygen in toluene at 110 degrees C produced the corresponding conjugated enones in yields up to 88% yield. The reaction of the same type failed on replacement of the silyl group at the C-3 position with an isopropyl group. These results indicate the existence(More)
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