Sunita Bhagat

A Facile Synthesis of Novel Spiro- [Indole-pyrazolinyl-thiazolidine]-2,4′-dione

Abstract A reaction of appropriate indol-2,3-diones with 4-aminoantipyrine has resulted in the formation of hitherto unknown 3-(2,3-dimethyl-5-oxo-1-phenyl-3-pyrazolin-4-yl-imino)-indol-2-ones in quantitative yields which upon cyclocondensation with mercaptoacetic acid afforded a series of new spiro heterocycles 3′-(2,3-dimethyl-5-oxo-1-phenyl-3-pyrazolin-4-yl) spiro[3H-indol-3,2′-thiazolidine]-2,4′-diones.

Synthesis of Some Novel bis‐Spiro[indole‐pyrazolinyl‐thiazolidine]‐2,4′‐diones

Abstract The reaction of 1H‐indol‐2,3‐diones with 1,6‐dibromohexane has resulted in the formation of new 1H‐indol‐2,3‐diones‐1,1′‐(1,6‐hexanediyl)bis in quantitative yields. These compounds have been used for the synthesis of novel [3′‐(2,3‐dimethyl‐5‐oxo‐1‐phenyl‐3‐pyrazolin‐4‐yl)spiro[3H‐indol‐3,2′‐thiazolidine]‐2,4′‐dione]‐1,1′‐(1,6‐hexanediyl)bis via bis Schiffs bases, [3‐(2,3‐dimethyl‐5‐oxo‐1‐phenyl‐3‐pyrazolin‐4‐yl) imino‐1H‐indol‐2‐one]‐1,1′‐(1,6‐hexanediyl)bis.

Novel Fluorinated Spiro [Indole-indazolyl-thiazolidine]-2,4′-diones: Design and Synthesis

The reaction of indol-2,3-diones ( 1a–i ) with 5-aminoindazole ( 2 ) has resulted in the formation of hitherto unknown 3-(indazol-5-yl)iminoindol-2-ones ( 3a–i ) in quantitative yields which, on 1,3-dipolar cyclocondensation with mercaptoacetic acid ( 4 ), has afforded a series of new spiro heterocycles, 3′-(indazol-5-yl) spiro[3H, indol-3, 2′ -thiazolidine]-2,4′-diones* ( 5a–i ).

Synthesis and in vitro antimicrobial evaluation of novel fluorine-containing 3-benzofuran-2-yl-5-phenyl-4,5-dihydro-1H-pyrazoles and 3-benzofuran-2-yl-5-phenyl-4,5-dihydro-isoxazoles

In the present study, some novel fluorine-containing heterocycles incorporating benzofuran with dihydropyrazoles and dihydroisoxazoles have been synthesized and evaluated for their in vitro antibacterial and antifungal activities. 2-Acetylbenzofuran on treatment with fluorinated aldehydes afforded corresponding fluorine-containing 1-benzofuran-2-yl-3-phenyl-prop-2-en-1-ones (chalcones 5a–g). The cyclocondensation of chalcones (5a–g) with hydrazine hydrate under basic conditions resulted in formation of corresponding novel fluorine-containing 3-benzofuran-2yl-5-phenyl-4,5-dihydro-1H-pyrazoles (6a–g). Similar reaction with hydroxylamine hydrochloride yielded 3-benzofuran-2yl-5-phenyl-4,5-dihydro-isoxazoles (7a–g). All the synthesized compounds have been characterized on the basis of analytical and spectral data, and were screened for their antibacterial and antifungal activities. Some of the synthesized compounds showed good antibacterial and antifungal activities.

Novel reaction products from simple organic reactions: Delineation of reaction pathways

In continuation of our interest in the synthesis of biologically active, natu- ral and synthetic compounds, we have come across some surprises even with simple reac- tions like alkylation, condensation and rearrangement, which have resulted in the forma- tion of some unusual novel products. Structures of these were assigned on the basis of their detailed spectral analysis and also confirmed in a few cases by X-ray crystal studies. Mechanistic aspects of the plausible routes of their formation have also been presented. NOVEL PRODUCTS OF FRIES REARRANGEMENT The Fries rearrangement is an exceedingly convenient and general method for the preparation of hydroxyketones from phenol esters and the formation of product(s) depends upon the reaction conditions used (ref. 1). It finds wide application in synthetic organic chemistry since both the acid and the phenol from which the phenol esters are derived can be varied. Metal promoted (ref. 2), anionic (ref. 3) and Photo Fries rearrangements (ref. 4), because of their specific advantages are gaining more importance these days for the regiospecific prepara- tion of varieties of new compounds. Beside these, Fries reaction has been also used for the preparation of various synthons, required for the synthesis of number of polycyclic compounds like benzofurans, steroids, coumarins and isocoumarins. We, in continuation of our interest in the field of natural product synthesis, envisaged the preparation of synthon 1, required for the synthesis of Candirone (5-hydroxy-2-(4-hydroxyphenyl)-3,6,8-trimethoxy-4H-1- benzopyran-Cone) (Z), isolated by Parmar et a1 (ref. 5), from the seeds of Tephrosiu cundidu. Interest in the synthesis of 2 was due to the rare oxygenation pattern (structure revised recently; ref. 6) and also because it was isolated from the extract that has been earlier found to possess strong insecticidal activity (ref. 7)Sarin et a1 (ref. 8) have also observed the activity against human epidermoid carcinoma of the nasopharynx in tissue culture (9KJ3) in 50% ethanolic extract of the plant. s

Synthesis of Some Salicylaldehyde-Based Schiff Bases in Aqueous Media

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Strategic synthesis and in vitro antimicrobial evaluation of novel difluoromethylated 1-(1, 3-diphenyl-1H-pyrazol-4-yl)-3, 3-difluoro-1, 3-dihydro-indol-2-ones

A new efficient and environmental friendly procedure for the synthesis of a series of salicylaldehyde-based schiff bases under microwave irradiation is described. The method is compared with the conventional method also. The present work involves condensation of salicylaldehyde with various aromatic amines in water under microwave irradiation. A judicious choice of the solvent and reaction conditions allowed the final products to be generated in excellent yields in a one-step procedure, whereas experiments under thermal conditions led to lower yields with tedious work-up. Microwave irradiation method gives advantages like reduction in reaction time, increase in conversion, reduced wastes, and good yields. The structures of synthesized compounds were confirmed by IR, 1HNMR, and Mass Spectra data.

Microwave Assisted Synthesis and in vitro Antimicrobial Activities of Fluorine Containing 4-Benzofuran-2-yl-6-phenyl-pyrimidin-2-ylamines

A strategic synthesis of 1-(1,3-diphenyl-1H-pyrazol-4-yl)-3,3-difluoro-1,3-dihydro-indol-2-ones has been achieved by the reaction of indole-2,3-dione (isatin) and substituted bromoacetyl benzene followed by cyclization reaction and evaluated for in vitro antibacterial and antifungal activities. Direct fluorination using diethylaminosulfur trifluoride as a nucleophilic fluorinating reagent was carried out in the present paper. Undoubtedly this methodology gives a facile and straightforward pathway to construct 1-(1,3-diphenyl-1H-pyrazol-4-yl)-3,3-difluoro-1,3-dihydro-indol-2-ones in good yields. The structure of new fluorinated 1-(1,3-diphenyl-1H-pyrazol-4-yl)-3,3-difluoro-1,3-dihydro-indol-2-ones was characterized based on 1H, 13C, and 19F nuclear magnetic resonance spectroscopy and mass spectrometry data. Structure of target compound was confirmed by Nuclear Overhauser Effect Spectroscopy spectra. Some of the synthesized compounds showed good antimicrobial activities against bacteria and fungi.

Solid support mediated chemo and regioselective synthesis of 3H-1,5- benzodiazepines from diversely substituted α-oxo ketene dithioacetals

A series of new analogs fluorine containing heterocyclic system viz. 4-benzofuran-2-yl-6-phenyl-pyrimidin-2- ylamine has been synthesized and evaluated for in vitro antibacterial and antifungal activities. Microwave assisted Claisen-Schmidt condensation of 2-acetylbenzofuran (3) with fluorinated benzaldehydes (4) afforded corresponding fluorinated chalcones (5a-g). The cyclocondensation of chalcones with guanidine hydrochloride in alkaline media under microwave resulted in the formation of corresponding fluorine containing 4-benzofuran-2-yl-6-phenyl-pyrimidin-2- ylamines (6a-g). All the synthesized compounds have been characterized on the basis of analytical and spectral data and were screened for their antibacterial and antifungal activities. Some of the synthesized compounds showed good antimicrobial activities against bacteria and fungi.

Recent Advances in Development of GPR40 Modulators (FFA1/FFAR1): An Emerging Target for Type 2 Diabetes.

Solvent free, dry media supported synthesis of a series of 4-aryl/heteroaryl-2-methylthio-3H-1,5-benzodiazepines by chemo- and regioselective cyclization of substituted α-oxoketene dithioacetals with o-phenylenediamines is described. The X-ray crystallographic studies confirmed the formation of the cyclized product.