S. Sarveswari

Flavonoid from Carica papaya inhibits NS2B-NS3 protease and prevents Dengue 2 viral assembly

Dengue virus belongs to the virus family Flaviviridae. Dengue hemorrhagic disease caused by dengue virus is a public health problem worldwide. The viral non structural 2B and 3 (NS2B-NS3) protease complex is crucial for virus replication and hence, it is considered to be a good anti-viral target. Leaf extracts from Carica papaya is generally prescribed for patients with dengue fever, but there are no scientific evidences for its anti-dengue activity; hence we intended to investigate the anti-viral activity of compounds present in the leaves of Carica papaya against dengue 2 virus (DENV-2). We analysed the anti-dengue activities of the extracts from Carica papaya by using bioinformatics tools. Interestingly, we find the flavonoid quercetin with highest binding energy against NS2B-NS3 protease which is evident by the formation of six hydrogen bonds with the amino acid residues at the binding site of the receptor. Our results suggest that the flavonoids from Carica papaya have significant anti-dengue activities. Abbreviations ADME - Absorption, distribution, metabolism and excretion, BBB - Blood brain barrier, CYP - Cytochrome P450, DENV - – Dengue virus, DHF - Dengue hemorrhagic fever, DSS - Dengue shock syndrome, GCMS - – Gas chromatography- Mass spectrometry, MOLCAD - Molecular Computer Aided Design, NS - Non structural, PDB - Protein data bank, PMF - Potential Mean Force.

Ultrasound-promoted synthesis of bi-, tri- and tetrapodal polyhydroquinolines, 1,4-dihydropyridines and the corresponding pyridines

Bi-, tri- and tetrapodal polyhydroquinolines and 1,4-dihydropyridines were synthesised by the reaction of various alkylating agents with polyhydroquinolines and 1,4-dihydropyridines under sonication conditions. These were in turn converted to the corresponding pyridines also using sonication. Sonication produced higher yields in a faster reaction time. All the synthesized compounds were characterized using spectral data.

Tert-butyl 3-oxo-2,3,4,5,6,7-hexa­hydro-1H-pyrazolo[4,3-c]pyridine-5-carboxyl­ate

In the title compound, C11H17N3O3, the pyrazole ring is approximately planar, with a maximum deviation of 0.005 (2) Å, and forms a dihedral angle of 5.69 (13)° with the plane through the six atoms of the piperidine ring. In the crystal, pairs of intermolecular N—H⋯O hydrogen bonds form dimers with neighbouring molecules, generating R 2 2(8) ring motifs. These dimers are further linked into two-dimensional arrays parallel to the bc plane by intermolecular N—H⋯O and C—H⋯O hydrogen bonds.

5-Methoxy-methyl-4-phen-oxy-1H-pyrazol-3-ol.

In the title compound, C11H12N2O3, the pyrazole ring system is essentially planar [maximum deviation = 0.002 (2) Å] and forms a dihedral angle of 66.93 (9)° with the benzene ring. In the crystal packing, pairs of intermolecular N—H⋯O and O—H⋯N hydrogen bonds connect neighbouring molecules into dimers, generating R 2 2(10) and R 2 2(8) ring motifs, respectively. The crystal structure is further stabilized by C—H⋯π interactions.

Microwave-assisted clean synthesis of xanthenes and chromenes in [bmim][PF6] and their antioxidant studies

Abstract An efficient one-pot synthesis of xanthene and chromene derivatives by three-component reactions of aryl aldehydes, cyclic 1,3-diketones, and 2-naphthol/4-hydroxy coumarin catalyzed by ionic liquid (IL) [bmim][PF6] under microwave irradiation is described. The present scheme provides several advantages such as short reaction time, mild reaction conditions, good yields, convenient operation, and reuse of IL. In vitro antioxidant activity was evaluated for the synthesized compounds by DPPH method. Compounds 6a, 6h, 6c, 6b, 4k, and 4a showed the highest antioxidant potency.

1-(6-Chloro-2-methyl-4-phenyl­quinolin-3-yl)-3-(3-methoxy­phen­yl)prop-2-en-1-one

In the title compound, C26H20ClNO2, the quinoline ring system is approximately planar with a maximum deviation of 0.028 (2) Å and forms a dihedral angle of 73.84 (5)° with the phenyl ring. Two neighbouring molecules are arranged into a centrosymmetric dimer through a pair of intermolecular C—H⋯Cl interactions. A pair of intermolecular C—H⋯O hydrogen bonds link two methoxyphenyl groups into another centrosymmetric dimer, generating an R 2 2(8) ring motif. The structure is further stabilized by C—H⋯π interactions.

(E)-1-(6-Chloro-2-methyl-4-phenyl-3-quinol­yl)-3-(2-methoxy­phen­yl)prop-2-en-1-one

In the title compound, C26H20ClNO2, the quinoline ring system and the methoxyphenyl ring form dihedral angles of 69.97 (6) and 22.10 (10)°, respectively, with the propenone linkage. The 4-phenyl ring substituent on the quinoline ring system is oriented at a dihedral angle of 66.47 (3)°. In the crystal, molecules exist as C—H⋯O hydrogen-bonded dimers. The structure is further stabilized by C—H⋯π interactions.

Growth, spectral, optical, thermal, surface analysis and third order nonlinear optical properties of an organic single crystal: 1-(2-Methyl-6-nitro-4-phenyl-3-quinolyl) ethanone.

Single crystal of 1-(2-Methyl-6-nitro-4-phenyl-3-quinolyl) ethanone was grown using slow evaporation solution growth technique. Single crystal X-ray diffraction study reveals the lattice parameters of the grown crystal. The modes of vibration of different molecular groups present in 2M6NQE were identified by FTIR spectral analysis. Its optical behavior was examined through UV-vis-NIR absorption and PL emission spectrum. They signify that the crystal has transparency in the region between 383 and 1100 nm. The PL spectrum of the title compound shows green emission in the crystal. From the thermal analysis, 2M6NQE has found to be thermally stable up to 263°C, and the melting point of the material is 170°C. The estimations of third order non-linear optical properties like non-linear absorption coefficient (β), non-linear refractive index (n2) and susceptibility [χ(3)] were calculated using Z-scan technique. It has observed that, crystal exhibits reverse saturation absorption and self-defocusing performance. Etching study was carried out for the grown crystal using different solvents.

β-Keto esters from ketones and ethyl chloroformate: a rapid, general, efficient synthesis of pyrazolones and their antimicrobial, in silico and in vitro cytotoxicity studies.

Background Pyrazolones are traditionally synthesized by the reaction of β-keto esters with hydrazine and its derivatives. There are methods to synthesize β-keto esters from esters and aldehydes, but these methods have main limitation in varying the substituents. Often, there are a number of methods such as acylation of enolates in which a chelating effect has been employed to lock the enolate anion using lithium and magnesium salts; however, these methods suffer from inconsistent yields in the case of aliphatic acylation. There are methods to synthesize β-keto esters from ketones like caboxylation of ketone enolates using carbon dioxide and carbon monoxide sources in the presence of palladium or transition metal catalysts. Currently, the most general and simple method to synthesize β-keto ester is the reaction of dimethyl or ethyl carbonate with ketone in the presence of strong bases which also requires long reaction time, use of excessive amount of reagent and inconsistent yield. These factors lead us to develop a simple method to synthesize β-keto esters by changing the base and reagent. Results A series of β-keto esters were synthesized from ketones and ethyl chloroformate in the presence of base which in turn are converted to pyrazolones and then subjected to cytotoxicity studies towards various cancer cell lines and antimicrobial activity studies towards various bacterial and fungal strains. Conclusion The β-keto esters from ethyl chloroformate was successfully attempted, and the developed method is simple, fast and applicable to the ketones having the alkyl halogens, protecting groups like Boc and Cbz that were tolerated and proved to be useful in the synthesis of fused bicyclic and tricyclic pyrazolones efficiently using cyclic ketones. Since this method is successful for different ketones, it can be useful for the synthesis of pharmaceutically important pyrazolones also. The synthesized pyrazolones were subjected to antimicrobial, docking and cytotoxicity assay against ACHN (human renal cell carcinoma), Panc-1 (human pancreatic adenocarcinoma) and HCT-116 (human colon cancer) cell line, and lead molecules have been identified. Some of the compounds are found to have promising activity against different bacterial and fungal strains tested.

(2E)-3-(4-Bromo-phen-yl)-1-(2-methyl-4-phenyl-3-quinol-yl)prop-2-en-1-one.

The conformation about the ethene bond [1.316 (3) Å] in the title compound, C25H18BrNO, is E. The quinoline ring forms dihedral angles of 67.21 (10) and 71.68 (10)° with the benzene and bromo-substituted benzene rings, respectively. Highlighting the non-planar arrangement of aromatic rings, the dihedral angle formed between the benzene rings is 58.57 (12)°.