Harshita Sachdeva

Microwave assisted one pot synthesis of a series of trifluoromethyl substituted spiro [indole–triazoles]

Abstract A series of trifluoromethyl substituted spiro [3H-indole-3,3′-[3H-1,2,4]triazoles]-2(1H)-ones have been synthesized in 85–90% yield by one pot environmentally benign microwave induced techniques involving the condensation of 3-arylimino-2H-indol-2-ones (III) with thiosemicarbazide (IV) using montmorillonite as solid support. This 3-arylimino-2H-indol-2-ones (III) was synthesized in situ by the reaction of fluorinated indole-2,3-diones (I) and fluorinated anilines (II). The advantages obtained by the use of microwave irradiation were demonstrated.

IMPROVED SYNTHESIS OF 3-SPIRO INDOLINES IN DRY MEDIA UNDER MICROWAVE IRRADIATION

An efficient, one-pot synthesis of novel spiro [indole-dipyrrolopyridines] (8) was achieved under microwave irradiation by the interaction of spiro [indole-dipyrrolopyrans] (3) with ammonium acetate (7) in the presence of acetic acid. Spiro [indole-dipyrrolopyrans] (3) were synthesized “in situ” by the reaction of indole-2,3-diones (1) and 2-pyrrolidone (2) in 1:2 molar ratio by microwave induced techniques for the first time. Comparative studies have been made between (a) microwave irradiation of (i) neat reaction of reactants in the absence of any solvent or catalyst (ii) reaction in presence of o-dichlorobenzene and (b) classical heating.

Montmorillonite catalysed synthesis of novel spiro[3H-indole-3,3'- [3H-1,2,4] triazol]-2(1 H ) ones in dry media under microwave irradiation

A new route for the one pot synthesis of novel spiro[3H-indole-3,3′-[3H-1,2,4] triazol]-2 (1H) ones utilizing 3-arylimino-2H-indol-2-ones (3) and thiosemicarbazide (4) as starting material under microwave irradiation is reported. Complete conversion was observed by TLC which also showed the formation of a single product.

NiO Nanoparticles: An Efficient Catalyst for the Multicomponent One-Pot Synthesis of Novel Spiro and Condensed Indole Derivatives

An efficient catalytic protocol for the synthesis of novel spiro[indoline-3,4′-pyrano[2,3-c]thiazole]carbonitriles and condensed thiazolo[5′′,4′′:5′,6′]pyrano[4′,3′:3,4]furo[2,3-b]indole derivatives is developed in a one-pot three-component approach involving substituted 1H-indole-2,3-diones, activated methylene reagent, and 2-thioxo-4-thiazolidinone under conventional heating and microwave irradiation. This paper describes the use of NiO nanoparticles as catalyst for the synthesis of novel spiro and condensed indole derivatives by Knoevenagel condensation followed by Michael addition. The advantageous features of this methodology are operational simplicity, high yield processing, and easy handling. The particle size of NiO nanoparticle was determined by XRD. After reaction course, NiO nanoparticles can be recycled and reused without any apparent loss of activity.

ZnO Nanoparticles as an Efficient, Heterogeneous, Reusable, and Ecofriendly Catalyst for Four-Component One-Pot Green Synthesis of Pyranopyrazole Derivatives in Water

An extremely efficient catalytic protocol for the synthesis of a series of pyranopyrazole derivatives developed in a one-pot four-component approach in the presence of ZnO nanoparticles as heterogeneous catalyst using water as a green solvent is reported. Greenness of the process is well instituted as water is exploited both as reaction media and medium for synthesis of catalyst. The ZnO nanoparticles exhibited excellent catalytic activity, and the proposed methodology is capable of providing the desired products in good yield (85–90%) and short reaction time. After reaction course, ZnO nanoparticles can be recycled and reused without any apparent loss of activity which makes this process cost effective and hence ecofriendly. All the synthesized compounds have been characterized on the basis of elemental analysis, IR, 1H NMR, and 13C NMR spectral studies.

Environ-Economic Synthesis and Characterization of Some New 1,2,4-Triazole Derivatives as Organic Fluorescent Materials and Potent Fungicidal Agents

A multicomponent one-pot clean cyclocondensation reaction of 4-chloro-2-nitro aniline/amino acids and aromatic aldehydes/indole-2,3-diones with thiosemicarbazide in water yielding triazole/spiro indole-triazole derivatives in high yields and shorter reaction time and displaying excellent florescent property is reported. The developed MCR may provide a valuable practical tool for the synthesis of new drugs containing the title core fragment. All the newly synthesized compounds have been characterized by IR, 1HNMR, 13CNMR, and fluorescence study and also been screened for antimicrobial activity.

Synthesis, anti-inflammatory activity, and QSAR study of some Schiff bases derived from 5-mercapto-3-(4′-pyridyl)-4H-1,2,4-triazol-4-yl-thiosemicarbazide

The purpose of this research is to synthesize better anti-inflammatory compounds derived from 5-mercapto-3-(4′-pyridyl)-4H-1,2,4-triazol-4-yl-thiosemicarbazide (5). 2-Substituted-N-[3-(pyridin-4-yl)-5-sulfanyl-4H-1,2,4-triazol-4-yl]hydrazine carbothioamide derivatives (6a–j)/(7a–e) are synthesized by the condensation of 5 with variously substituted aromatic aldehydes/1H-indole-2,3-diones, respectively, under conventional and microwave irradiation methods. The microwave method is found to be superior with higher chemical yields, tremendous reduction in time, and is environmentally benign as compared to conventional heating method. The chemical structures of the newly synthesized compounds (6/7) have been confirmed by IR, 1H NMR, and 13C NMR spectra and have been evaluated for anti-inflammatory activity by carrageenan-induced acute paw edema method in rats.

Nano-ZnO Catalyzed Multicomponent One-Pot Synthesis of Novel Spiro(indoline-pyranodioxine) Derivatives

A simple catalytic protocol for the synthesis of novel spiro[indoline-pyranodioxine] derivatives has been developed using ZnO nanoparticle as an efficient, green, and reusable catalyst. The derivatives are obtained in moderate to excellent yield by one-pot three-component reaction of an isatin, malononitrile/ethylcyanoacetate, and 2,2-dimethyl-1,3-dioxane-4,6-dione in absolute ethanol under conventional heating and microwave irradiation. The catalyst was recovered by filtration from the reaction mixture and reused during five consecutive runs without any apparent loss of activity for the same reaction. The mild reaction conditions and recyclability of the catalyst make it environmentally benign synthetic procedure.

Alum Catalyzed Simple, Efficient, and Green Synthesis of 2-(3-Amino-5-methyl-5-(pyridin-3-yl)-1,5-dihydro-4H-1,2,4- triazol-4-yl)propanoic Acid Derivatives in Aqueous Media

Alum (KAl(SO4)2 ·12H2O) is an inexpensive, efficient, and nontoxic catalyst used for the synthesis of 2-[3-amino-5-methyl-5-(pyridin-3-yl)-1,5-dihydro-4H-1,2,4-triazol-4-yl]propanoic acid derivatives in aqueous media by the reaction of 3-acetyl pyridine (1), amino acids (2)/(6), and thiosemicarbazide (4) at 80°C. This methodology offers significant improvements for the synthesis of products with regards to the yield of products, simplicity in operation, and green aspects by avoiding toxic catalysts which uphold the motto of green chemistry. Synthesized compounds have been characterized by FT-IR, 13C NMR, and 1HNMR spectroscopy.

Facile One Pot Microwave Induced Synthesis of Spiro [Indole-pyrazoles] and Spiro [indol-isoxazoles]

The potential of domestic microwave oven has been utilized in an elegant one step synthesis of a series of new fluorine containing spiro [indole-pyrazoles] and spiro [indol-isoxazoles] in 85-95% yields. Results were compared with those obtained following the classical method which involves synthesis in three steps. The advantages obtained by the use of microwave irradiation were demonstrated.