Vijai N. Pathak

Mild and Ecofriendly Tandem Synthesis, and Spectral and Antimicrobial Studies of N1-Acetyl-5-aryl-3-(substituted styryl)pyrazolines

N1-acetyl-5-aryl-3-(substituted styryl)pyrazolines were synthesized by the cyclocondensation of 1,5-substituted diphenyl-1,4-pentadien-3-ones with hydrazine hydrate and a cyclizing agent such as acetic acid in ethanol. The title compounds were synthesized using conventional and solvent-free approaches, which involves mechano-chemical mixing, microwave-irradiation, and ultrasound-irradiation methods in the presence of a solid support. The synthesized compounds have been characterized by elemental analyses and spectral data (IR, PMR, and FAB-mass). All the synthesized compounds have been evaluated for their antibacterial and antifungal activities. Some compounds have shown promising biological activity.

Studies in fluorinated 1,3-diketones and related compounds Part XII. Synthesis and spectroscopic studies of some new polyfluorinated 1,3-diketones, and their copper 1,3-diketonates

Abstract New polyfluorinated 1,3-diketones have been prepared from polyfluorinated acetophenones and appropriate esters in the presence of sodamide. The corresponding copper 1,3-diketonates have been obtained by treating a methanolic solution of polyfluorinated 1,3-diketone with methanolic solution of copper acetate. The polyfluorinated 1,3-diketones have been characterized by elemental as well as by spectral studies, viz: I.R., 1 H N.M.R. and 19 F N.M.R. In I.R., characteristic absorptions observed are: CF stretching bands (1300 − 1000) cm −1 , CF deformation modes (900 − 700 cm −1 ) and intramolecular hydrogen bonding (3000 − 2500 cm −1 ). In 1 H N.M.R. methine ( = C H ) signal is observed at δ 6.2 − 6.8 ppm and enolic proton resonance signal at δ 13 − 15 ppm indicating the presence of strong hydrogen bonding in such polyfluorinated 1,3-diketones.

Synthesis of Some Novel 2,3,4,8,9‐Pentahydro‐7‐(4‐haloaryl)‐pyrazolo[5,1‐e]benzo[1,5]oxazocines and 2,3(erythro), 7,8‐Tetrahydro‐2‐aryl‐3‐(4‐fluoro‐3‐methylbenzoyl)‐6‐(4‐haloaryl)pyrazolo[5,1‐d] Benzo[1,4]oxazepines via Solid–Liquid PTC

Abstract In this communication, a simple and straightforward procedure for the heterocyclization of 1H‐4,5‐dihydro‐3‐(4‐haloaryl)‐5‐substituted phenylpyrazoles (4) with 1‐bromo‐3‐chloropropane and 2,3‐dibromo‐1‐(4‐fluoro‐3‐methylphenyl)‐3‐phe‐ nylpropanone affording 2,3,4,8,9‐pentahydro‐7‐(4‐haloaryl)pyrazolo[5,1‐e]benzo[1,5] oxazocines 5 and regioselective synthesis of 2,3(erythro),7,8‐tetrahydro‐2‐ aryl‐3‐(4‐fluoro‐3‐methylbenzoyl)‐6‐(4‐halophenyl)pyrazolo[5,1‐d]benzo[1,4]oxa‐ zepines 6, respectively, via solid–liquid PTC is reported. All the synthesized compounds have been characterized on the basis of their spectral studies (IR, PMR, and MS) and analytical data.

Studies in fluorinated 1,3-diketones and related compounds Part X. Synthesis of some new polyfluorinated 1,3-diketones, their copper 1,3-diketonates and spectral studies

Uber die Friedel-Crafts-Acylierung der Fluorbenzole (I) mit Acetylchlorid (II) sind die fluorierten Acetophenone (III) zuganglich, die mit Trifluoressigsaureethylester (IV) zu den 1,3-Diketonen (V) kondensiert werden.

Facile synthesis of fluorine containing imidazo [1,2-b] [1,2,4] triazines through α-oxo-n-aryl-α arylethanehydrazonoyl bromides

Abstract Treatment of fluorine containing arylglyoxals with aminoguanidine bicarbonate in aqueous ethanol formed fluorinated 3-amino-5-aryltriazines which in turn ontreatment with α-oxo-N-aryl-α-arylethanehydrazonoyl bromides afforded 3,6-diaryl-7-arylazoimidazo[1,2-b][1,2,4] triazines in 75–80% yield. All the compounds were characterized by their analytical and spectral (IR, PMR and Mass) data. Mass fragmentation patterns of these compounds have also been discussed. The screening of biological activities are in progress.

Studies of fluorinated β-diketones and related compounds. Part II. Synthetic and infrared spectral studies of 1,3-diketonatochromium derivatives, and their substitution reactions

Seventeen 1,3-diketonatochromium derivatives have been prepared from fluorinated β-diketones, and their electrophilic substitution reactions have been studied. Chloro-, bromo-, and nitro-substituents have been introduced at the central carbon atom of the ligand under controlled conditions. The effect of these groups on CO and CC stretching frequencies is discussed.

Studies of fluorinated β-diketones and related compounds. Part 6. Synthesis and spectroscopic studies of some new fluorinated β-thioxo-ketones and their copper chelates

Twelve new fluorinated β-thioxo-ketones have been prepared from the corresponding fluorinated acetophenones and appropriate O-alkyl thioesters in the presence of sodamide, and have been characterized as copper chelates. These β-thioxo-ketones exist entirely in the hydrogen-bonded enol form ArC(OH)CH·CSR, as evidenced by i.r. and n.m.r. spectra.

Synthesis and Spectral Studies of Some New bis(1,3‐Diketonato)palladium(II) Complexes

Bis(1,3‐diketonato)palladium(II) complexes were synthesized by three routes. In route one, sodium hexachlorodipalladate in methanol was treated with the appropriately substituted diaryl‐1,3‐diketones using sodium carbonate, while in route two substituted diaryl‐1,3‐diketones were treated with palladium chloride in acetone to afford the desired bis(1,3‐diketonato)palladium(II). In route three 1,3‐bis(substituted aryl)prop‐2‐enones were treated with palladium chloride and sodium hydrogen carbonate in THF to provide the oxygen insertion product, bis(1,3‐diketonato)palladium(II) complexes. All synthesized compounds were characterized on the basis of spectral and analytical data.

Synthesis and Spectral Studies of Some Novel 2,5,9,10-Tetrahydro [7,8-g]benzo-8-arylpyrazolo[4,5-e][1,5-b]benzoxazonine via Phase Transfer Catalysis

Abstract Treatment of 1H-4,5-dihydro-3-aryl-5-(2-hydroxyaryl)pyrazole with o-dibromoxylene under liquid-liquid phase transfer catalytic conditions using tetra-n-butylammonium hydrogen sulphate or [18]-crown-6 as PT catalyst, benzene/chloroform as organic phase and 50% aqueous potassium hydroxide as second phase, afforded novel 2,5,9,10-tetrahydro [7,8-g] benzo-8-arylpyrazolo[4,5-e] [1,5-b] benzoxazonines.

Studies in fluorinated 1,3-diketones and related compounds Part XV. Synthesis and spectroscopic studies of some new fluorinated monothio-1,3-diketones

Abstract Six new polyfluorinated monothio-l,3-diketones have been synthesized from the corresponding fluorinated aceto- phenones and appropriate 0-alkyl thioesters in the presence of sodamide. All these monothio-1,3-diketones are characterized by I.R. and 1 H N.M.R. spectral studies.