Shivapura Viveka

Preparation and Properties of Biodegradable Film Composites Using Modified Cellulose Fibre-Reinforced with PVA

Cellulose has a potential to become a key resource in the development of biodegradable film composites. In this work, cellulose was modified by using 2-(Trifluromethyl)benzoylchloride by base-catalyzed reaction. Modification of cellulose was confirmed by IR studies. The biodegradable composite films were developed by film casting method using modified cellulose with Poly(vinyl alcohol) in different compositions. The film composites were characterized by mechanical, moisture absorption, gas barrier, and biodegradable properties. Obtained films have shown transparency and flexibility and displayed good mechanical properties. Film composites also showed good biodegradability. Better barrier properties showed by film composites as the percentage of modified cellulose increased. This indicates the importance of modified cellulose as a reinforcing agent. After evaluating these properties of film composites, we came to conclusion that these biocomposites can be used to membrane and packaging applications.

Design, synthesis, anticonvulsant and analgesic studies of new pyrazole analogues: a Knoevenagel reaction approach

The present work involves the design and synthesis of a number of new compounds starting from 3-(3,4-dihalophenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde. The compounds were synthesized by adopting the Knoevenagel condensation reaction to meet the structural prerequisite required for anticonvulsant and analgesic activities. The reaction of 3-(3,4-dihalophenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde with substituted thiazolidine, pyrazolone, thiazolo[3,2-a]pyrimidine, Meldrums acid and barbituric acid yielded a variety of heterocycles bearing the pyrazole moiety. The newly synthesized compounds were characterized by elemental and spectroscopic analysis; in addition, the structure of compound 1a has been elucidated by single crystal X-ray diffraction technique. The synthesized molecules were evaluated for their in vivo anticonvulsant activity using maximal electroshock seizure (MES) test, while their analgesic activity was investigated by tail flick method. Further, rotarod toxicity method was used to study the toxicity profile of the selected compounds. Among the synthesized compounds, 1a, 4a and 7a possessed potent anticonvulsant activity and 1b, 5a, 5b, 7a and 7b showed the highest analgesic activity without displaying any toxicity. Efforts were also made to establish structure–activity relationships among the tested compounds.

Synthesis, characterization of new imidazoquinonyl chalcones and pyrazolines as potential anticancer and antioxidant agents

In the present work, we report the facile synthesis, characterization and anticancer, antioxidant study of new imidazoquinoline carrying biologically active chalcone (2a–d) and pyrazoline (3a–d, 4a–d) moieties. Pyrazoline derivatives (3a–d, 4a–d) have been synthesized from the intermediate chalcones (2a–d) by cyclizing with hydrazine hydrate and phenyl hydrazine. The structures of these compounds were confirmed by IR, 1H NMR, 13C NMR and LC–MS. Biological studies of the synthesized compounds showed promising anticancer and antioxidant activities. The compounds were tested for their in vitro anticancer activity against human cell culture HeLa (cervical cancer) cell line. Compounds 2d and 3d showed the highest cytotoxicity. Compounds 2a, 2d and 3d are found to be the most effective antioxidant agents. Thus, the results show that synthesized compounds possess anticancer and antioxidant activity.

Preparation and Characterization of Modified Cellulose Fiber-Reinforced Polyvinyl Alcohol/Polypyrrolidone Hybrid Film Composites

In this work, cellulose was modified by using 2-(trifluromethyl)benzoylchloride by base catalyzed reaction. Modification of cellulose was confirmed by IR studies. The biodegradable composite films were developed by a film casting method using modified cellulose with poly(vinyl alcohol) and polypyrrolidone in different compositions. Film composites showed good biodegradability. Better barrier and mechanical properties showed by film composites as the percentage of modified cellulose increased. This indicates the importance of modified cellulose as a reinforcing agent. After analyzing these properties of film composites we came to the conclusion that, these biocomposites can be used for membrane and packaging applications.

Ethyl 7-Methyl-5-(4-methylphenyl)-3-oxo-2-{(3-(3,4- dichlorophenyl)-1-phenyl-1H-pyrazol-4-yl)methylidene}-2,3- dihydro-5H-(1,3)thiazolo(3,2-a)pyrimidine-6-carboxylate

A simple route for synthesis of compound 3 via three component reaction involving ethyl 6-methyl-4-(4-methylphenyl)-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (1), 3-(3,4-dichlorophenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde (2) and monochloroacetic acid is described. The newly synthesized compound is well characterized by elemental analysis, IR, 1H-NMR and mass spectral studies.

Synthesis, Crystal Structure, and Characterization of New 2,4,5-Triphenyl Imidazole: 4,5-Diphenyl-2-(3,4,5-trimethoxyphenyl)-1H-imidazole

The substituted triarylimidazole, C24H22N2O3, was prepared from the three-component one-pot condensation reaction and the product was crystallized by using dimethylformamide. The structure of the compound was confirmed by elemental analysis, FT-IR, thermogravimetric analysis (TGA), UV-Visible and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic crystal system in the space group P21/c with unit cell parameters a = 10.509(3) Å, b = 18.748(5) Å, c = 22.016(6) Å, β = 90.844(5)°, and Z = 8. The crystal structure of the compound was stabilized by the inter-molecular interactions of types N–H⋅⋅⋅N, C–H⋅⋅⋅O, and C–H⋅⋅⋅N, and intra-molecular interactions of the type C–H⋅⋅⋅O. The structure also involves C–H⋅⋅⋅π interactions.

Synthesis Characterization and Crystal Structure of 2-(3,4,5-trimethoxyphenyl)-1-(4-fluorophenyl)-4,5-diphenyl-1H-imidazole

The title compound, C30H25FN2O3, was prepared from the four-component one-pot condensation reaction and the product crystallized using dimethylformamide. The structure of the compound was established by elemental analysis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), UV-Visible, and single-crystal X-ray diffraction. The compound crystallizes in the triclinic crystal system with the space group Pī, with unit cell parameters a = 10.286(2) Å, b = 11.795(2) Å, c = 21.331(4) Å, α = 100.270(3)°, β = 90.093(3)°, γ = 90.062(3)°, and Z = 4. The crystal and molecular structure of the title molecule is stabilized by intra-molecular interactions of types C–H···N and C–H···O.

Structural, spectral, and theoretical investigations of 5-methyl-1-phenyl-1H-pyrazole-4-carboxylic acid

The present research work has focused on combined experimental and theoretical studies of one of the biologically important pyrazole-4-carboxylic acid derivatives, viz. 5-methyl-1-phenyl-1H-pyrazole-4-carboxylic acid (C11H10N2O2). The starting material 5-methyl-1-phenyl-1H-4-pyrazolecarboxylate (1) was obtained by the cyclocondensation of ethyl acetoacetate, N,N-dimethylformamide dimethyl acetal (DMF-DMA), and phenylhydrazine, which upon basic hydrolysis yielded the corresponding acid (2). The target compound (2) was characterized by 1H and 13C NMR (solution in DMSO), Fourier transform infrared (FT-IR) spectroscopy, thermo gravimetric analysis, and by single-crystal X-ray diffraction technique. The single crystals of compound (2) were obtained at room temperature by slow evaporation of ethanol as solvent and crystallized in the space group P21/n of monoclinic system. The experimental FT-IR and 1H and 13C NMR chemical shifts have been compared to those calculated by means of density functional theory (DFT) at the B3LYP/TZ2P level of theory. The continuum-like screening model was used for geometry optimization of a single molecule and for subsequent calculations of NMR shielding constants in solution (DMSO). Finally, the HOMO–LUMO energy levels were also constructed to study the electronic transition within the molecule by time-dependent TD-DFT method.

Synthesis, characterization, and pharmacological screening of new 1,3,4-oxadiazole derivatives possessing 3-fluoro-4-methoxyphenyl moiety

Within the past years, many researches on the synthesis, structure–activity relationships (SAR), antimicrobial and antioxidant activities of the 1,3,4-oxadiazole derivatives have been reported. Several 1,3,4-oxadiazole derivatives possess important pharmacological activities and they have been proved useful materials in drug research. New series of 1,3,4-oxadiazole derivatives incorporating a 3-fluoro-4-methoxyphenyl moiety of pharmacological significance has been synthesized through multistep reaction. Structures of newly synthesized compounds were characterized by spectroscopic methods. New compounds were screened for their in vitro antimicrobial and antioxidant activities. Three compounds were found to be active antimicrobial agents and three compounds having potent antioxidant activity in comparison with the standard drug.Graphical Abstract

1-{4-((1-Isobutyl-1H-imidazo(4,5-c)quinolin- 4yl)amino)phenyl}ethanone

The title compound (3) is synthesized by the nucleophilic substitution of 4-chloro-1-isobutyl-1H-imidazo[4,5-c]quinoline 2 with 4-amino acetophenone in n-butanol. Newly prepared imiquimod derivative (3) is characterized by IR, NMR and mass spectral data.