Measurement of K β K /α values using proton beamvalues using proton beam

The Measurement of K _β K _/α intensity ratios are measured in some 3d shell elements by using a 2 MeV proton beam along with a high resolution Si(Li) detector. The present Measurement of K _β K _/α intensity ratios are in good agreement with Scofield modified theoretical values, thus supporting the basic assumptions in that theory. From the present Measurement of K _β K _/α intensity ratios, it is evident that due to chemical effects, the experimental Measurement of K _β K _/α intensity ratios will be increased while they will be decreased due to the presence of simultaneous M-shell vacancies which are produced due to proton excitation.     

The facile and efficient organocatalytic platform for accessing 1,2,4-selenadiazoles and thiadiazoles under aerobic conditions

The first organocatalytic approach towards synthesis of rarely explored 1,2,4-selenadiazole and thiadiazole scaffolds have been devised using corresponding carboxamides as substrates. The transformations were realized using two distinct conditions in the presence of catalytic vitamin B₃ or thiourea under aerobic conditions. Developed methods overcome the associated limitations of previous reported approaches and the desired products were obtained in high yields and selectivity without the formation of toxic side-products.     

An Improved Process for the Enantioselective Synthesis of HCV NS5A Inhibitor Elbasvir (MK-8742) Chiral Amine Intermediate

Russian Journal of General Chemistry - Large-scale enantioselective synthesis of the chiral amine unit of HCV NS5A inhibitor Elbasvir has been accomplished in six steps, with 55% overall yield. The...     

Facile combustion synthesis of Ag2O nanoparticles using cantaloupe seeds and their multidisciplinary applications

Silver oxide nanoparticles (Ag₂O NPs) were prepared using cantaloupe (Cucumis melo) seeds as a fuel by employing a green synthesis method. The prepared Ag₂O NPs were investigated using powder X-ray diffraction (PXRD), UV–visible spectrum, Fourier transform infrared analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy-dispersive spectroscopy, and photoluminescence studies. PXRD data reveal the establishment of cubic crystal structure of Ag₂O NPs. According to SEM and TEM results, the morphology of the prepared NPs was agglomerated and spherical. The photodegradation activity of the prepared Ag₂O NPs over methylene blue dye was promising under visible light irradiation. Furthermore, the antimicrobial assay of the synthesized Ag₂O NPs was carried out by the disc diffusion method against Gram-positive and Gram-negative microbial strains.     

Synthesis of isoamyl acetate usin NaX and NaY zeolites as catalysts

A liquid phase esterification reaction between glacial acetic acid and isoamyl alcohol has been studied using NaX and NaY zeolites as catalysts. The influence of calcination temperature, the amount of catalysts, reaction temperature, time of esterification and the molar ratio of the reactants has been investigated. Water insoluble products have been isolated from the reaction mixture and analyzed for the ester. Both NaX and NaY are found to be active as catalysts in the reaction. However, their catalytic activity varies with the reaction conditions and their calcination temperature. The reaction has been found to be 100% selective to ester formation. Catalytic activity of the zeolites has been correlated with their surface acidity.     

Regioselective synthesis of 2-carbonyl furans in a one pot three component reaction

Regioselective synthesis of 2-benzoyl-6,6-dimethyl-6,7-dihydrobenzofuran-4(5H)-ones have been accomplished through a novel protocol involving β-amino enone, N-chlorosuccinimide and dimedone in a one pot catalyst-free reaction at an ambient temperature. On the other hand, the same reaction when conducted with two equivalents of N-chlorosuccinimide under similar reaction conditions, exclusive formation of 2-benzoyl-3-(dimethylamino)-6,6-dimethyl-6,7-dihydrobenzofuran-4(5H)-ones were observed. Simple and metal-free reaction conditions, selective product formation and excellent yields are the advantages of this protocol.     

Friedlander synthesis of highly functionalized isoxazolyl quinoline libraries via addition of C(sp3)–H bond to aldehydes

A novel protocol for ionic liquid (IL)-mediated C(sp³)–H bond functionalization of 3,5-dimethyl-4-nitroisoxazoles 4 to substituted o-amino benzaldehydes 5 was developed in excellent yields. Isoxazolyl aryl ethanones 7 have been synthesized from isoxazolyl aryl ethanol synthon 6. Furthermore, utilizing the later as synthons for IL promoted Friedlander synthesis of highly functionalized isoxazole substituted quinoline libraries 9. The merit of this synthesis is easily available and economical starting materials, effective utilization of all the reactants, and simple workup procedure. It is noteworthy that ionic liquid used in C(sp³)–H bond functionalization and Friedlander synthesis reactions can be recycled and reused five times without significant decrease in activity.     

Development and substantiation of a liquid chromatographic method for monitoring organic reactions involved in synthesis of 4-methoxyphenylacetic acid

A simple and rapid reversed-phase high-performance liquid chromatographic method for monitoring the reactions involved in two different processes for the production of 4-methoxyphenylacetic acid (PMPA) was developed. Impurity profiles of PMPA were used for fingerprinting of the two different synthetic processes by HPLC. Impurities were separated and determined on a Hypersil C18 column with acetonitrile-0.1 M potassium dihydrogen orthophosphate-triethylamine (40:59.95:0.05, v/v) (pH 3.0) as the mobile phase and detection at 280 nm at ambient temperature. The method was substantiated with respect to accuracy, precision, linearity, robustness, limit of detection and quantification. The method was found to be suitable not only for monitoring the reactions but also for quality assurance of PMPA as it could detect impurities at the level of 4 x 10(-9) g.     

CeCl3·7H2O: a highly efficient catalyst for the synthesis of 1-substituted-octahydro-[1,3,2]diazaphospholo[1,5-a]pyridine-1-oxide

An efficient and simple protocol is reported for the synthesis of a new class of 1-substituted-octahydro-[1,3,2]diazaphospholo[1,5-a]pyridine-1-oxides in good to excellent yield (88–95%) via Michaelis–Arbuzov rearrangement. Condensation of diamido phosphite with various halides at 60 °C using CeCl₃·7H₂O as a highly efficient catalyst afforded the products within a short period of reaction time. This procedure is mild, efficient, and non-toxic and stability of the catalyst is the merit of this process. Therefore, this protocol being environmentally benign and efficient, serves as an alternative procedure for the preparation of the title compounds.     

Copper catalyzed access to functionalized oxazoles from oximes via carbenoids

An operationally simple, economical and straightforward synthesis of diverse oxazoles from oximes possessing a vicinal carbonyl group has been achieved by treatment of the latter with terminal diazo compounds like ethyl/benzyl diazoacetate and diazoacetophenone (which act as carbenoids) in one pot. At least two reducible functional groups (two ester groups or cyano?+?ester) are simultaneously introduced in one step. This reaction involves expulsion of a molecule each of N₂ and water only as byproducts under copper catalysis. The structure of one of these oxazoles is confirmed by X-ray crystallography. Both the ester groups in the oxazole product could be reduced to alcohol moieties by using NaBH₄/EtOH.