One-pot three-component synthesis of twelve different chromeno[2,3-b]indole derivatives were achieved by the condensation of β-naphthol, oxindole and various substituted aldehydes. Two more chromeno[2,3-b]indole derivatives were also synthesized through one-pot two-component condensation of salicylaldehyde with oxindole/chlorooxindole. Both the condensations were achieved by using Keggin-type heteropoly-11-molybdo-1-vanadophosphoric acid, H4[PVMo11O40] supported on montmorillonite K-10 clay for about 10% as catalyst under environmentally benign solvent-free reaction condition. Shorter reaction time, excellent yield of product, sustainability of catalytic material and simple workup procedure under green experimental conditions are the advantages of this protocol.
Mosquitoes have developed resistance to various synthetic insecticides, making their control increasingly difficult. Insecticides of botanical origin may serve as suitable natural control. This study evaluates the toxic potential of Ocimum canum (Sims) leaf extract and powder against Anopheles stephensi (Liston), Aedes aegypti (Lin) and Culex quinquefasciatus (Say) larval and adult mosquitoes. Larval mortality was observed after 24 h recovery period and adult smoke toxicity observed for 40 min duration at 10 min interval. Methanol extract of O. canum showed highest larval mortality against the larvae of C. quinquefasciatus LC50 = 28.3225, LC90 = 44.1150; Ae. aegypti LC50 = 43.327, LC90 = 61.249; and An. stephensi LC50 = 30.2001, LC90 = 48.2866 ppm. The smoke toxicities were 93% mortality in C. quinquefasciatus, 74% in Ae. aegypti and 79% in An. stephensi adults, respectively, whereas 100% mortality was recorded in the commercial mosquito control. Our results suggest that O. canum leaf extract and powder are natural insecticide, and ideal eco friendly approach for mosquito control. 相似文献
Isothermal-isobaric ensemble Monte Carlo simulation of adamantane has been carried out with a variable shape simulation cell. The low-temperature crystalline phase and the room-temperature plastic crystalline phases have been studied employing the modified Williams potential. We show that at room temperature, the plastic crystalline phase transforms to the crystalline phase on increase in pressure. Further, we show that this is the same phase as the low-temperature ordered tetragonal phase of adamantane. The high-pressure ordered phase appears to be characterized by a slightly larger shift of the first peak toward a lower value of r in C-C, C-H, and H-H radial distribution functions as compared to the low-temperature tetragonal phase. The coexistence curve between the crystalline and plastic crystalline phase has been obtained approximately up to a pressure of 4 GPa. 相似文献
In this report, we present a simple wet chemical route to synthesize nano-sized silver particles, and their surface properties are discussed in detail. Silver nano particles of the size 40–80 nm are formed in the process of oxidation of glucose to gluconic acid by amine in the presence of silver nitrate, and the gluconic acid caps the nano silver particle. The presence of gluconic acid on the surface of nano silver particles was confirmed by XPS and FTIR studies. As the nano silver particle is encapsulated by gluconic acid, there was no surface oxidation, as confirmed by XPS studies. The nano silver particles have also been studied for their formation, structure, morphology and size using UV–Visible spectroscopy, XRD and SEM. Further, the antibacterial properties of these nano particles show promising results for E. Coli. The influence of the alkaline medium towards the particle size and yield was also studied by measuring the pH of the reaction for DEA, NaOH and Na2CO3. 相似文献
One-pot multi-component synthesis of N,N′-alkylidene bisamides, 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted imidazoles in the presence of catalytic material heteropoly-11-tungsto-1-vanadophosphoric acid (HPV) supported on activated natural clay for about 20% (HPVAC-20) under solvent-free reaction condition have been achieved. Green heterogeneous reaction condition, simple workup procedure, short reaction time, high yield of products, and reusability of the catalyst are the advantages of this protocol. 相似文献
The volatile oil of the leaves of Pogostemon heyneanus Benth. (Lamiaceae) was analyzed by GC and GC-MS. Twenty-six components representing 96.0% of the oil were identified. The major components of the oil were acetophenone (51.0%), beta-pinene (5.3%), (E)-nerolidol (5.4%), and patchouli alcohol (14.0%). Comparison of the compositions of the oils of P. heyneanus and P. cablin (Blanco) Benth. (Patchouli oil) showed wide variation between them. Though 13 sesquiterpenes and oxygenated sesquiterpenes were detected in both oils, their concentrations in the oils differed widely. Acetophenone, benzoyl acetone and (E)-nerolidol present in the oil of P. heyneanus were not detected in patchouli oil. 相似文献
Design of experiment (DOE) based on central composite design (CCD) has been employed for the development of a mathematical
model correlating the important process parameters like thiourea concentration (U), annealing temperature (A), rotational speed (S), and annealing time (T) of the spin coating process for the preparation of CdS thin films. The experiments were conducted as per the design matrix.
Nanocrystalline CdS thin films have been prepared using cadmium nitrate and thiourea as precursors by sol gel spin coating
method using the results of the mathematical model. The prepared CdS films have been characterized and the crystal structure
and grain size of the samples were analyzed using X-ray diffraction technique. The adequacy of the developed models was checked
by analysis of variance (ANOVA) technique. The accuracy of prediction has been carried out by conducting confirmation test.
Using this model, the main effect of process parameters on grain size of CdS films have been studied. These parameters were
optimized to obtain minimum grain size using the Microsoft excel solver. The results have been verified by depositing CdS
films using the optimized conditions. These films have been characterized using X-ray diffraction technique and the grain
size is found to be 8.8 nm. The high resolution transmission electron microscopy (HRTEM) analysis showed the grain size of
the prepared CdS film to be ∼7 nm. UV–vis spectroscopy analysis revealed that CdS films exhibited quantum confinement effect. 相似文献
Present work deals with the preparation of TiO2 thin films of different thicknesses by PVD technique using an electron beam and to characterize the films for oxygen gas
detection. The films were characterized using optical transmission measurements, XRD and atomic force microscopy. From the
spectral data, the extinction, absorption coefficient and refractive index of the films are evaluated and reported. The optical
band gap energy varies between 3 and 3.68 eV. The XRD pattern confirms the formation of polycrystalline anatase structure
of Titanium with preferred orientation of (110) plane. The AFM images indicate the presence of coarse and fine grains with
uniform as well as smooth surfaces over the entire range of the analyzed surface. Response characteristics of TiO2 thin films for oxygen gas detection are studied, which indicate a low response time of 120 seconds and high sensitivity of
16 at the operating temperature 450 °C.
Paper presented at the 2nd International Conference on Ionic Devices, Anna University, Chennai, India, Nov. 28–30, 2003. 相似文献