Synthesis and spectral characterization of some new N-substituted 2-aminobenzothiazoles, 2-aminothiazolopyridines and 2-aminothiazoloquinolines

A series of N-substituted 2-aminobenzothiazoles, 2-aminothiazolopyridines, and 2-aminothiazoloquinolines were prepared by the cyclization of N,N'-disubstituted thiourea derivatives by bromine in acetic acid. The uv, ir and nmr data for these compounds are presented and discussed.     

Chemical sensing of Benzo[a]pyrene using Corchorus depressus fluorescent flavonoids

Plant phytochemicals, such as flavonoids are in use for the development of optical biosensor. Benzo[a]pyrene (B[a]P), is a pervasive environmental and dietary carcinogen. A fluorescent assay is developed using plant isolated flavonoid for the detection of B[a]P. High content saponins are excluded from the flavonoid-containing methanolic extract of Corchorus depressus by implying reduction of silver ions by saponins resulting in formation of silver nanoparticles. Isolated plant flavonoids are used to develop a spectrofluorometric assay for the detection of B[a]P. Decrease in the flavonoid fluorescence intensity by B[a]P is found to be based on both static and dynamic quenching. Specificity of the assay for B[a]P was tested for other carcinogens belonging to different classes of compounds. Flavonoids-mediated sensing can be implied for the development of new generation of nanoparticle-based biosensors that can be more sensitive and less susceptible to external factors, such as temperature and humidity.     

DFT study of the infrared and Raman spectra of photochromic Fulgide; 3-Dicyclopropylmethylene-4-E-[1-(2,5-dimethyl-3-furyl)ethylidene]-5-(4-nitrophenylcyanomethylenetetrahydrofuran-2-one

The present work reports a theoretical study of vibrational signatures of the photochromic molecular transformation between two photochromic heterocyclic isomers. Raman and infrared (IR) spectra of the E (ring-opened form) and C (ring-closed form) photoisomers of 3-Dicyclopropylmethylene-4-E-[1-(2,5-dimethyl-3-furyl)ethylidene]-5-(4-nitrophenylcyanomethylenetetrahydrofuran-2-one have been calculated in gas phase in the region of 3500–500 cm^?1 for both molecules in their ground state. Calculations of the structure parameters and frontier molecular orbitals were carried out using ab initio electronic structure theory at the Hartree-Fock, density functional theory, and Moller-Plesset perturbation theory levels, while calculations of the IR and Raman spectra were carried out using density functional theory with B3LYP functional and 6-31+g(d,p) basis set. After comparing the predicted spectra of both E-form and C-form, we were able to probe the changes that arise upon the ring-closure/ring-opening transformation. The computational results showed that the C-form is ≈?10.7 kcal/mol lower in energy than the E-form. In addition, two different derivatives were adopted for both E-form and C-form to demonstrate the effect of substituents on the stability of the photoisomers. The theoretical predictions agree well with the reported experimental data, accounting for the molecular structure transformation of the photochromic isomers.     

DABCO–PEG ionic liquid-based synthesis of acridine analogous and its inhibitory activity on alkaline phosphatase

In world, many people struggle with viral, parasitic, bacterial, cancer, and other diseases. Therefore, numerous chemists seek to develop less toxic, more selective, and effective medicines. Most therapeutic medicines are based on inhibition of specific enzymes. Acridines are interesting heterocyclic structures that are much sought after targets attributed to their wide biological activities and feature to display potent enzymes inhibitory effects. Their approach of action is owing to DNA interaction and subsequent effects on the biological functions linked to DNA and associated enzymes. In this regards, we synthesized acridine analogous through 1,4-diazabicyclo[2.2.2]octane (DABCO)–polyethylene glycol-400 (PEG-400) mediated ionic liquid approach. DABCO–PEG-400-mediated IL was prepared through the DABCO alkylation using 1-bromopentane followed by mixing with PEG-400. The synthesized analogous were investigated as inhibitors of alkaline phosphatase, which is a nonspecific phosphomonoester hydrolase that catalyzes the hydrolysis of broad spectrum of organic monophosphates. Analogue viz. 3,3,6,6-tetramethyl-9-(4-nitrophenyl)-2,3,4,5,6,7,9,10-octahydroacridine-1,8-dione was found to be potent alkaline phosphatase inhibitor.     

Photoluminescence emission behavior on the reduced band gap of Fe doping in CeO2-SiO2 nanocomposite and photophysical properties

Fe/CeO₂-SiO₂ nanocomposite was synthesized via hydrothermal method. Bond length of nanocomposite was determined through FTIR analysis, while Raman analysis showed lattice relaxation of CeO₂ phase in Fe/CeO₂-SiO₂. TEM, XRD and DLS-PSA revealed an increase in size of Fe/CeO₂-SiO₂ as compared to CeO₂-SiO₂ which was attributed to have more oxygen vacancies in CeO₂ after doping of iron. Lattice contraction was also observed in some phases of CeO₂ in Fe/CeO₂-SiO₂ nanocomposite as compared to CeO₂-SiO₂ nanocomposite. This contraction was used for determination of Fe content incorporated in CeO₂ [1 1 1] phase. The band gap values of Fe/CeO₂-SiO₂ nanocomposite were found reduced after doping of Fe by factors of 0.62 and 0.55 eV, respectively. Photoluminescence study of the materials was carried out to study the different type of transitions occurring after absorption of electromagnetic radiation. Photoluminescence intensity at 2.12 eV was found enhanced after doping of Fe due to increased oxygen vacancy. Photocatalytic activity of the nanocomposites was studied with the degradation of chlorpyrifos pesticide.     

Merging image databases as an example for information integration

Central European Journal of Operations Research - By integrating information we mean pulling information pieces from various sources together with as little loss of information and as little...     

Influence of nozzle area ratio on the gas-particle flow for single-hose dry ice blasting nozzle

Journal of Thermal Analysis and Calorimetry - In this paper, a numerical study was performed to examine the effect of divergent nozzle length of single-hose dry ice blasting on the development of...