Various isoindolo[2,1‐a]quinazoline‐5,11‐dione derivatives 3 were synthesized in good yields by means of the reductive reaction of N‐substituted 2‐nitrobenzamides 1 and 2‐formylbenzoic acids 2 in the presence of SnCl2?2 H2O under reflux in EtOH (Scheme, Table). The procedure needed two steps, the reduction of the nitro group of the 2‐nitrobenzamide and ring closure by nucleophilic addition of the NH2 group to both the formyl and carboxylic acid C?O groups. 相似文献
The implantation of nitrogen into silicon to produce Si3N4 layers was investigated to find an alternative to CVD-Si3N4 layers used in ISOPLANAR-and LOCOS-technology. The technological properties of the implanted Si3N4 layers in respect to oxidation inhibition and etching are comparable or superior to CVD-Si3N4 layers. The implanted layers are more resistent against oxidation for nitrogen doses of 2.4×1017 cm−2 at 30keV. The etching behavior is comparable for both types of Si3N4-layers. In the implanted layers no pinholes are found and threre is no formation of a bird's beak, as is well known in the
case of CVD-nitride. 相似文献
The annealing behavior of arsenic-implanted silicon under scanned cw CO2-laser irradiation from front and back surfaces is investigated. Ellipsometry, Hall effect, Rutherford backscattering measurements
and neutron activation analysis indicate an enhancement of annealing efficiency by laser irradiation from the back surface,
which provides complete recovery of crystal damage, high substitutionality and electrical activation of implanted arsenic
atoms without redistribution of concentration profile. The enhancement of annealing efficiency under back-surface irradiation
is explained by the difference in laser reflection from the front and back surface of silicon wafers. No differences in the
results are found for scanned and static annealing. 相似文献
The green reaction of isatoic anhydrides with α-amino acids in presence of the ionic liquid 1-butyl-3-methylimidazolium bromide
afforded 1,4-benzodiazepine-2,5-diones in excellent yields in absence of a catalyst. The reaction workup is simple and the
ionic liquid was easily recovered from the reaction and reused. The methodology was quite general and a range of cyclic and
acyclic α-amino acids were examined to produce 1,4-benzodiazepine-2,5-diones. 相似文献
The green reaction of isatoic anhydrides with α-amino acids in presence of the ionic liquid 1-butyl-3-methylimidazolium bromide
afforded 1,4-benzodiazepine-2,5-diones in excellent yields in absence of a catalyst. The reaction workup is simple and the
ionic liquid was easily recovered from the reaction and reused. The methodology was quite general and a range of cyclic and
acyclic α-amino acids were examined to produce 1,4-benzodiazepine-2,5-diones.
Correspondence: Khosrow Jadidi, Department of Chemistry, Shahid Beheshti University, PO Box 1983963113, Tehran, Iran. 相似文献
Three generations of water-soluble flavin dendrons have been synthesized and the role dendrimer generation has on the physical and catalytic properties of these assemblies has been investigated. 相似文献
Solubilization and interaction of azo-dye light yellow (X6G) at/with cationic surfactants cetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPC) was investigated spectrophotometricaly. The effect of cationic micelles on solubilization of anionic azo dye in aqueous micellar solutions of cationic surfactants was studied at pH 7 and 25 degrees C. The binding of dye to micelles implied a bathochromic shift in dye absorption spectra that indicates dye-surfactant interaction. The results showed that the solubility of dye increased with increasing surfactant concentration, as a consequence of the association between the dye and the micelles. The binding constants, K(b), were obtained from experimental absorption spectra. By using pseudo-phase model, the partition coefficients between the bulk water and surfactant micelles, K(x), were calculated. Gibbs energies of binding and distribution of dye between the bulk water and surfactant micelles were estimated. The results show favorable solubilization of dye in CTAB micelles. 相似文献
An in-situ formed polymer–based dispersive solid phase extraction in combination with solidification of floating organic droplet-based dispersive liquid–liquid microextraction was developed for the extraction of neonicotinoid pesticides from milk samples. The extracted analytes were determined using high-performance liquid chromatography–diode array detector. In this approach, after precipitating the proteins of milk using a zinc sulfate solution, the supernatant phase (containing sodium chloride) was transferred into another glass test tube, and a homogenous solution of polyvinylpyrrolidone and a suitable water-miscible organic solvent was rapidly injected into it. By this step, the polymer particles were re-produced and the analytes were extracted onto the sorbent surface. In the following step, the analytes were eluted with an appropriate organic solvent to use in the following solidification of floating organic droplet-based dispersive liquid–liquid microextraction step that was done to acquire the low limits of detection. Under the optimized conditions, satisfactory results consisting of low limits of detection (0.13–0.21 ng/ml) and quantification (0.43–0.70 ng/ml), high extraction recoveries (73%–85%), and enrichment factors (365–425), and good repeatability (relative standard deviations equal or less than 5.1% and 5.9% for intra- and inter-day precisions, respectively) were obtained. 相似文献
In this study the researcher reports a novel, one step synthesized rod-like nanoparticles of cerium (III)—tetraphenylporphyrin sandwich complex as a spectrofluorometric sensor to measure trace amount of Hg (II) and Cu (II) metal ions. Moreover, the synthesized fluorescent probe was able to detect higher amounts (>10?4 M) of Hg (II) in aqueous media by changing the color which can also be used as a selective mercury naked-eye sensor. The selectivity and sensitivity of the sensor based on its fluorescence quenching in the presence of Hg (II) and Cu (II) were studied according to the Stern-Volmer equation. The detection limit of the sensor was 16 nM for Hg (II) and about 2.34 μM for Cu (II) ions.