Publications by authors named "Yuvaraj Arun"

Polyanhydrides have been synthesized for decades by melt-polycondensation of diacid monomers and 5 to >10 times mole excess acetic anhydride to diacid monomers to form polymers with a polydispersity ranging from 2.5 to 6 and low reproducibility. Hydrophobic segments in polyanhydrides are beneficial to hinder the characteristic hydrolytic cleavage of an anhydride bond that provides stable polyanhydrides at room temperature.

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The alternating architecture and hydrophobic side chains hinder hydrolytic cleavage and anhydride interchange in poly(sebacic acid-ricinoleic acid) (P(SA-RA)), which provides stable polyanhydrides at room temperature. In this report, a series of polyanhydrides were designed to investigate the effect of ester bonds, hydrophobic side chains, phenyl moieties, and their distance from anhydride bonds on their stability and properties. Polyanhydrides with alternating architecture are constructed by the polymerization of ester-diacids prepared from ricinoleic or other hydroxy acids with anhydrides such as succinic, maleic, and phthalic anhydrides.

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Two novel pyrazole based thiourea palladium(II) complexes, [PdCl(PPh)(CHNOS-pz)] (1) and [PdCl(PPh)(CHNOS-pz)] (2) [pz = pyrazole (CHN)] have been obtained unexpectedly from chromone thiosemicarbazones (L1 and L2) and [PdCl(PPh)]. The compounds have been fully characterized by physicochemical studies. The single crystal X-ray diffraction and spectral studies revealed square planar geometry for the complexes.

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New 1,4-disubstituted β-pyrrolidino-1,2,3-triazoles were synthesized using a reusable copper-iodide-doped neutral alumina catalyst. Synthesis of diversely substituted triazoles and recyclability of CuI catalyst explains the broad scope of this protocol. The synthesized compounds were screened for their antimicrobial and anticancer properties.

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Rhodium-catalysed decarbonylative annulation of isatoic anhydrides with alkynes through C-H activation for the synthesis of aminoisocoumarins was developed. This enables the gram-scale transformation to iodoisocoumarin which is a vital building block in transition-metal-catalysed cross couplings. These compounds exhibit blue-emitting luminescence properties.

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Background: Callistemon citrinus has been traditionally known for its medicinal property. Recently, our research group identified 1,8-Cineole, as one of the predominant compound present in the hexane extract (HE-C), whose leaves have potent anticancer activity.

Hypothesis/purpose: The present study was designed to isolate 1,8-Cineole from Callistemon citrinus plant and to determine their role in anticancer effects in in vitro using skin carcinoma cells.

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A facile ruthenium(II)-catalyzed regiospecific C-H/O-H oxidative annulation methodology was developed to construct isochromeno[8,1-]phenazines. This methodology delivers various advantages, such as scope for diverse substrates, tolerance to a range of functional groups, stability under air, and yields regioselective products. This methodology was successfully applied to synthesize far red (FR) fluorescent probes for live cancer cell imaging.

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A series of new Ni(II) complexes containing indole-based thiosemicarbazone ligands was synthesized and characterized by elemental analyses, and UV-visible, FT-IR, H & C NMR and mass spectroscopic techniques. The Ni(II) complexes (1-4) bear the general formula [Ni{CHNNHCSNH(R)}] where R = hydrogen (1), 4-methyl (2), 4-phenyl (3) and 4-cyclohexyl (4). Molecular structure of ligands (L3 and L4) and complexes (2, 3 and 4) was confirmed by single crystal X-ray crystallography.

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Rhodium catalysed dehydrogenative C-H/N-H functionalization was developed to construct phthalazino[2,3-a]-/indazolo[1,2-a]cinnolines by reacting N-phenyl phthalazine/indazole with alkynes. The synthesized compounds exhibit prominent fluorescence properties in solid and aggregation states. Their application in cell imaging was investigated using various cancer cell lines.

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In the title compound, C25H20N6O2·0.15H2O, the dihedral angles between the least-squares planes of the indole and pyrrolidine rings and between the oxindole and imidazole rings are 77.66 (7) and 45.

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In the title compound, C31H25N5O3·C2H6OS, the three indole/indoline units are all essentially planar with maximum deviations of 0.0172 (3), 0.053 (2) and 0.

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In the title compound, C26H20N4O2S, the central pyrrolidine ring adopts a twist conformation on the C-C bond involving the spiro C atom. Its mean plane makes dihedral angles of 78.83 (14), 65.

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The title compound, C(24)H(29)NO(7), is asymmetric with a chiral centre located in the pyran ring and crystallizes as a racemate. The coumarin ring system and the fused pyran ring make a dihedral angle of 10.46 (8)°.

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A series of novel spirooxindoles have been synthesized through 1,3-dipolar cycloaddition of an azomethine ylide generated from isatin and sarcosine or l-proline with the dipolarophile 1,4-naphthoquinone followed by spontaneous dehydrogenation. Synthesised compounds were evaluated for their antimicrobial activities against eight bacteria and three fungi. All the spirooxindole derivatives exhibited significant antibacterial activity against Staphylococcus aureus, S.

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The title compound, C(26)H(33)NO(7), comprises a racemic mixture of asymmetric mol-ecules containing one stereogenic centre. The dihedral angle between the mean planes of the fused pyran ring and the coumarin ring system is 8.12 (14)°.

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The title compound, C(20)H(21)NO(7), is asymmetric with a chiral centre located in the pyran ring and crystallizes as a racemate. The mol-ecular framework is somewhat bent; the coumarin moiety and the pyran ring are inclined by 7.85 (5)°.

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