Synthesis and biological evaluation of benzimidazole-oxindole conjugates as microtubule-targeting agents.

A series of benzimidazole-oxindole conjugates were synthesized and evaluated for their cytotoxic activity. The cytotoxicity assay results suggest that conjugates 5c and 5p exhibit promising cytotoxicity against human breast cancer cell line (MCF-7). The Cell cycle analysis revealed that these conjugates induced cell cycle arrest at G2/M phase in MCF-7 cells. The tubulin polymerization assay results suggested that these conjugates inhibit tubulin polymerization with IC50 values 1.12 and 1.59µM respectively. Immunofluorescence analysis also suggested that these conjugates effectively inhibited the microtubule assembly in MCF-7 cells. Further, molecular docking studies indicated that these conjugates 5c and 5p interact and binds efficiently with the tubulin protein. By and large, the results demonstrated that these benzimidazole-oxindole conjugates possess cytotoxic property by inhibiting the tubulin polymerization.

Synthesis, spectral characterization, electron microscopic study and thermogravimetric analysis of a phosphorus containing dendrimer with diphenylsilanediol as core unit.

A phosphorus containing dendrimer with a diphenylsilanediol core was synthesized using a divergent method. Several types of reactions were performed on dendrons of several sizes, either at the level of the core or the surface. The giant Schiff's base macro molecule possesses 12 imine bonds and 8 hydroxy groups on the terminal phenyl groups. The structures of the intermediate compounds were confirmed by IR, GCMS and ³¹P NMR. The final compound was characterized by ¹H, ¹³C, ³¹P NMR, MALDI-TOF MS and CHN analysis. Scanning electron microscopic and thermogravimetric analysis/differential scanning calorimetric studies were also performed on the final dendritic molecule.

Synthesis, spectral characterization and bioassay of 3,3'-(1,4-phenylene)-bis[2-alkoxycarbonyl-alkyl)-2-thio-benzoxa-phosphinines].

Synthesis of 3,3'-(1,4-phenylene)-bis[2-alkoxycarbonyl-alkyl)-2-thio-benzoxaphos-phinines] (3a-j) were accomplished via two step process. It involves the prior preparation of monochloride intermediate (2) and its subsequent reaction with the amino acid esters in dry tetrahydrofuran-toluene in the presence of triethylamine at reflux temperature. These compounds were characterized by IR, 1H, 13C, 31P NMR and were found to exhibit potent in vitro antioxidant activity.

Diethyl [(5-chloro-2-hydroxy-anilino)(4-chloro-phen-yl)meth-yl]phospho-nate.

In the title compound, C(17)H(20)Cl(2)NO(4)P, the P atom is bonded in a distorted tetra-hedral environment. The dihedral angle between the two benzene rings is 80.5 (1)°. In the crystal structure, inter-molecular O-H⋯O and N-H⋯O hydrogen bonds link pairs of mol-ecules into centrosymmetric dimers. These dimers, are in turn, linked by weak inter-molecular C-H⋯O hydrogen bonds into one-dimensional chains along [010]. Additional stabilization is provided by very weak C-H⋯Cl inter-actions.

3-(6-Methyl-2-pyrid-yl)-2-phenyl-3,4-dihydro-1,3,2-benzoxaza-phosphinine 2-oxide.

In the title compound, C(19)H(17)N(2)O(2)P, the six-membered 1,3,2-oxaza-phosphinine ring adopts a boat conformation with the phosphoryl O atom in an equatorial position. The dihedral angle between the 6-methyl-2-pyridyl and phenyl groups is 75.5 (1)°. These substituents are trans to each other, and are oriented at angles of 57.2 (1) and 74.8 (1)°, respectively, to the benzene ring. The crystal structure is stabilized by intra- and inter-molecular hydrogen bonds. The phosphoryl O atom participates in inter-molecular C-H⋯O inter-actions with the neighbouring mol-ecules, forming centrosymmetric R(2) (2)(14) dimers.

Synthesis and anticancer activity of new class of bisphosphonates/phosphanamidates.

Novel bis-heterocyclic bisphosphonates/phosphonamidates were synthesized utilizing the Pudovick reaction. The employment of Nb(2)O(5) as catalyst was found to increase the yields and purity of the bisbenzoxazaphosphine derivatives (13a-h). Their anticancer activity studies in vitro, on three human tumor cell lines NCI-H460 (lung large cell), MCF-7 (breast adenocarcinoma), and SF-268 (central nervous system glioblastoma), showed that bis-[3-(3-chloro-4-fluorophenyl)-2-oxo-3,4-dihydro-2H-2lambda(5)-benzo[e][1,3,2]oxazaphosphinin-2-yl]arylmethanes (13a-h) and [(4-chlorophenyl)-(hydroxyamidophosphinoyl)-methyl]phosphonic acid (14) exhibited significant anticancer activity.

Synthesis and bioactivity of some new N-aryl/alkyl/cyclohexyl-N'-(2,3-dihydro-2-oxo-4H-benz[e][1,3,2]oxazaphosphorin-2-yl) ureas.

Several new substituted oxazaphosphorinyl urea derivatives of the type RR'P(O)NHC(O)NHR'' were synthesized from alpha-(3-chloro-4-fluoroanilino)-o-cresol by reaction with chlorides of aryl/alkyl/cyclohexyl carbamidophosphoric acids in the presence of triethylamine at 0-50 degrees C. Their significant insecticidal and antimicrobial activity and promotion of Rhizobium bacteria growth in the soil without effect on the host tissue suggests their possible commercial application as ecofriendly pesticides and antimicrobial agents.