Synthesis of novel 1,2,3-triazole substituted-N-alkyl/aryl nitrone derivatives, their anti-inflammatory and anticancer activity.

A series of novel 1,2,3-triazole substituted N-phenyl nitrone derivatives 5a-e were prepared in three steps starting from 1-substituted-1,2,3-triazole-4-carbaldehydes 2 via Schiff's base formation, reduction followed by oxidation. Similarly, 1,2,3-triazole substituted N-alkyl nitrone derivatives 6a-p were prepared in single step starting from compound 2 on reaction with N-alkyl hydroxylamine hydrochlorides. All the final compounds were screened for anti-inflammatory and anticancer activity against various cancer cell lines. Among the compounds tested, the compounds 5a, 5d, 6a, 6b, 6m and 6o exhibited significant inhibition of IL-1ß secretion as a measure of anti-inflammatory activity. Compound 5b, 5c, 6h, 6i and 6o exhibited significant activity against all the cell lines (A549, COLO 205, MDA-MB 231 and PC-3) at IC50 values of <15 µM.

Synthesis of novel 1,2,3-triazole/isoxazole functionalized 2H-Chromene derivatives and their cytotoxic activity.

A series of novel 2-(1,2,3-triazolylmethoxy) 5a-q and isoxazole tagged 6a-g 2H-Chromene derivatives were prepared starting from salicylaldehyde and ethyl-4,4,4-trifluoroacetoacetate via cyclization to form ethyl 2-hydroxy-2-(trifluoromethyl)-2H-Chromene-3-carboxylate 3. Compound 3 on reaction with propargyl bromide resulted compound 4 and was independently reacted with aryl/alkyl azides and aryl aldoximes obtained 2-(1,2,3-triazolylmethoxy) and isoxazole tagged 2H-Chromene derivatives 5a-q, 6a-i, respectively. Compounds 6 were further hydrolysed to acid derivatives 7a-g. All the products 5a-q, 6a-i, 7a-g were screened for cytotoxic activity against four human cancer cell lines and among all the compounds, 5f, 5g, 5l, 5q showed promising activity at <20 µM concentration.

Synthesis of novel 5-(3-alkylquinolin-2-yl)-3-aryl isoxazole derivatives and their cytotoxic activity.

The propargyl alcohol on reaction with aldoxime and NaOCl in DCM gave exclusively (3-arylisoxazol-5-yl) methanol 1. The compound 1 was oxidized to an aldehyde 2 followed by reaction with aniline resulted in Schiff's base 3. The compounds 3 were further reacted with various aldehydes having α-hydrogen using molecular iodine as catalyst and which yielded 5-(3-alkylquinolin-2-yl)-3-aryl isoxazole derivatives 4. All the final compounds 4 were screened against four human cancer cell lines (A549, COLO 205, MDA-MB 231 and PC-3) and among these compounds 4n showed potent cytotoxicity against all the cell lines at IC50 values of <12 µM.

Synthesis of novel 2-alkyl triazole-3-alkyl substituted quinoline derivatives and their cytotoxic activity.

The propargyl alcohol on reaction with alkylazides under Sharpless conditions through click chemistry concept gave exclusively 1,4-disubstituted triazoles 2. The compounds 2 were oxidized to aldehydes 3 followed by reaction with aniline resulted Schiff's bases 4. The compounds 4 was further reacted with various aldehydes having α-hydrogen using molecular iodine as a catalyst and obtained 2-alkyl triazole-3-alkyl substituted quinoline derivatives 5. All the final compounds were screened against four human cancer cell lines (THP-1, Colo205, U937 & HeLa) and promising compounds have been identified.

Aqua-(2,2'-bipyridine-κ²N,N')(2-methyl-malonato-κ²O¹,O³)copper(II) dihydrate.

In the title compound, [Cu(C4H4O4)(C10H8N2)(H2O)]·2H2O, the Cu(II) ion displays a slightly distorted square-pyramidal coordination. The water mol-ecule at the apical position shows a long bond [Cu-O = 2.276 (2) Å]. The basal plane is formed by two N atoms of the 2,2'-bipyridine ligand and two carboxyl-ate O atoms from a malonate group. The five-membered chelate ring is almost planar [maximum deviation = -0.006 (2) Å], while the six-membered chelate ring defined by the malonate ligand adopts a distorted boat conformation. In the crystal, Cu(II) complex mol-ecules and lattice water mol-ecules are connected by O-H⋯O and C-H⋯O hydrogen bonds. The crystal packing is further stabilized by π-π inter-actions [centroid-centroid distances = 3.563 (2)-3.828 (2) Å].

Synthesis and spectroscopic characterization of Cu(II) containing chlorocadmiumphosphate Cd(HPO4)Cl·[H3N(CH2)6NH3]0.5 crystals.

Chlorocadmiumphosphate Cd(HPO(4))Cl·[H(3)N(CH(2))(6)NH(3)](0.5) crystals containing Cu(II) ions have been successfully synthesized at room temperature by using organic amine 1,6-diamino hexane as a template. The samples are characterized by X-ray powder diffraction, Thermal and spectroscopic studies. These are crystallizes in the monoclinic crystal system with cell dimensions: a=1.7697, b=0.6576, c=1.9026nm and ß=106.5°. FT-IR spectrum showed the absorption bands related to PO(4), NH(3)(+) ions and other organic molecule vibrations originated from the templated molecule. The prepared crystals are stable at room temperature and as well as up to around 300°C which were confirmed by thermal analysis. Optical absorption and EPR studies suggest that Cu(II) ion enters in to the lattice as tetragonally distorted octahedral symmetry, for which crystal field and spin-Hamiltonian parameters are calculated. Bonding parameters are suggesting that there exists partial covalent nature between Cu(II) ions and ligands.

Chlorido(4-methylpyridin-2-amine-κN (1))(2-{[(4-methylpyridin-2-yl)imino-κN]methyl}phenolato-κO)copper(II).

In the title complex, [Cu(C13H11N2O)Cl(C6H8N2)], the Cu(II) atom adopts a distorted tetra-hedral geometry being coordinated by the phenolic O atom and the azomethine N atom of the Schiff base ligand N-salicyl-idene 2-amino-pyridine, and by the 2-amino-pyridine N atom and a Cl atom. The pyridyl N atom of the Schiff base and the imino N atom of the 4-methyl-pyridine-2-yl-imino ligand are not involved in the coordination. There is an intra-molecular N-H⋯N hydrogen bond involving the pyridine N atom and the amino group of the 2-amino-pyridine ligand. In the crystal, mol-ecules are linked via N-H⋯Cl hydrogen bonds, forming chains propagating along [001].

Synthesis of novel alkyltriazole tagged pyrido[2,3-d]pyrimidine derivatives and their anticancer activity.

A series of novel alkyltriazole tagged pyrido[2,3-d]pyrimidine derivatives 5 and 6 was prepared starting from 2,3-active functional pyridine 1via cyclization, propargylation followed by reaction with alkyl or perfluoroalkyl azides under Sharpless conditions. All the compounds 5 and 6 were screened for anticancer activity against three cancer cell lines such as U(937), THP-1 and Colo205. The promising compounds 5b and 5e have been identified.

Spectroscopic and electrochemical studies of hetero-bimetallic copper complexes with Schiff's base ligand.

Using Schiff's base ligand, several Cu(II) based bimetallic complexes such as Cu-Cu, Cu-Co, Cu-Ni, Cu-Zn, Cu-Mn have been prepared in a stepwise procedure. The structures of these complexes and the ligand have been proposed on the basis of FAB mass, elemental analysis, UV-vis, IR, electron paramagnetic resonance (EPR) and CV studies. EPR parameters, obtained through complete simulation, suggest that the formation of bimetallic complexes forces the Cu(II) centre to increase the flexibility in comparison with the monometallic Cu(II) complex. However, the nature of the second metal ion in the bimetallic complex effects the distortion around the first metal ion. The reduction of the complexes from Cu(II) to Cu(I) involves a large geometrical change and is found to be irreversible. A large positive shift is seen in the cathodic process, which can be ascribed to increased distortion due to bimetallic coordination. These complexes have potential usage in DNA studies.

EPR of vanadyl impurity in zinc ammonium trihydrogen bis(orthophosphate) monohydrate single crystal.

The electron paramagnetic resonance spectroscopic investigation of VO(II)-doped zinc ammonium trihydrogen bis(orthophosphate) monohydrate single crystal has been carried out at 300K. The single crystal, rotated along the three orthogonally crystallographic axes, have yielded spin Hamiltonian parameters g and A as: g(xx)=1.978, g(yy)=1.974, g(zz)=1.925 and A(xx)=7.4, A(yy)=7.8, A(zz)=19.4 mT. These spin Hamiltonian parameters reflect a slight deviation from axially symmetry to rhombic, which is elucidated by the interstitial occupation of the vanadyl ion. The isofrequency plots and EPR spectra at few orientations have been simulated using the calculated spin Hamiltonian parameters. The Fermi contact parameter (kappa) and dipolar interaction parameter (P) have been calculated as 0.857 and -128 x 10(-4)cm(-1), respectively. The percentage of metaloxygen bond has been identified as 20%.