Heterogeneous catalyst SiO2-LaCl3·7H2O: characterization and microwave-assisted green synthesis of α-aminophosphonates and their antimicrobial activity.

Silica-supported lanthanum (III) chloride (SiO2-LaCl3·7H2O) was prepared and characterized by infrared spectroscopy, X-ray diffraction analysis, scanning electron microscope, energy-dispersive X-ray spectroscopy, thermogravimetric analysis and differential thermal analysis techniques. The catalytic activity of this silica-supported lanthanum (III) chloride was investigated in a one-pot three-component Kabachnik-Fields reaction. A library of new α-aminophosphonates was prepared employing various benzothiazole and thiadiazole amines, different substituted aldehydes and diethylphosphite under solvent-free conditions using conventional/microwave methods with good to excellent yields (85-97%). The advantages of this catalyst are that it is environmentally benign, economically inexpensive, and easy to prepare, gives high yields and high purity is less time-consuming, offers easy purification is reusable and enables products to be obtained by simple recrystallization without column chromatography.

Isolation and characterization of plumbagin (5- hydroxyl- 2- methylnaptalene-1,4-dione) producing endophytic fungi Cladosporium delicatulum from endemic medicinal plants: Isolation and characterization of plumbagin producing endophytic fungi from endemic medicinal plants.

The rationale of the present study was to isolate and identify endophytic fungi from endemic medicinal plants in Eastern Ghats and screened for antimicrobial potential of isolated fungal crude extracts. A total of 329 endophytic strains were isolated from 600 infected leaves and stem cuttings of endemic plants. The diversity and species richness was analyzed statistically and found to be higher in leaf segments than in stem segments. From isolated fungal strains, Cladosporium delicatulum was identified using molecular identification methods and selected as the most potent plumbagin-producing endophytic strain. Further the isolation and structural characterization of endophytic fungal plumbagin (5-hydroxyl-2-methylnaptalene-1,4-dione) was purified and confirmed through spectroscopy analysis. The molecular weight was determined as m/z 188 in positive mode by ESI-MS, which confirmed to be plumbagin which potentially inhibited all tested pathogens, therefore the endophytic fungal plumbagin from the current study possesses important biological activities against pathogens.