Use of allylzinc halide as a source of halide: Differential addition of nucleophiles to Ts-aziridines and aldehydes under similar reaction conditions

We have observed that the allylic zinc halide under identical reaction conditions acts in different modes for different electrophiles. For Ts-aziridines the halide part of the allylic halide has been introduced as a nucleophile and for the carbonyl compounds the simple allylation reaction occurs. To the best of our knowledge this is the first report where the allylic zinc halide is the source of halide acting as nucleophile. The main advantages of the present procedure are easy to handle, no need of inert atmosphere, mild reaction conditions, and applicability to a wide variety of substrates for aziridines and carbonyl compounds.     

Recent advances on heterocyclic compounds with antiviral properties

Chemistry of Heterocyclic Compounds - In recent years several important viral infections have emerged and antiviral chemotherapeutic agents are not sufficiently effective in clinic, leading to...     

Formylation without catalyst and solvent at 80 °C

A simple and efficient protocol for N-formylation of aliphatic and heterocyclic amines has been described with formic acid in the absence of catalyst and solvent.     

Pumice-based sulfonic acid: a sustainable and recyclable acidic catalyst for one-pot synthesis of pyrazole anchored 1,4-dihydropyridine derivatives at room temperature

Research on Chemical Intermediates - In the present investigation, we have developed an efficient and eco-friendly protocol for the synthesis of pyrazole anchored 1,4-dihydropyridine analogs using...     

Comparative Analysis of the Properties of Tween‐20, Tween‐60, Tween‐80, Arlacel‐60, and Arlacel‐80

Foamability and foam stability, emulsifying power, surface tension, and interfacial tension were investigated for Tween‐20 (polyoxyethylene sorbitan monolaurate), Tween‐60 (polyoxyethylene sorbitan monostearate), Tween‐80 (polyoxyethylene sorbitan monooleate), Arlacel‐60 (Sorbitan stearate), and Arlacel‐80 (Sorbitan oleate). Among all the surfactants tested for their foaming power and foamabilty, Arlacel‐60 and Arlacel‐80 showed the best results; the foaming power and foamability was found to be 100%. The surfactants having foam stability more than 50% can be considered as metastable and those less than 50% are considered as low‐stability foams. In case of surface tension and interfacial tension property measurements, Arlacel‐80 showed the best results. At 1% surfactant concentration, the surface tension and interfacial tension of Arlacel‐80 was found to be 29.9 dynes/cm and 1.1 dynes/cm at 30°C ambient temperature. Also, Arlacel‐60 was found to exhibit the best emulsifying power among all the surfactants tested. At 30°C, the emulsifying property of Arlacel‐60 was 6 hours.     

Indium triflate‐catalyzed one‐pot synthesis of 14‐alkyl or aryl‐14H‐dibenzo[a,j]xanthenes in water

A mild, efficient, and environment friendly method has been developed for the synthesis of 14‐alkyl or aryl‐14H‐dibenzo[a, j]xanthenes by condensation of 2‐naphthol and aldehydes in the presence of a catalytic amount of indium(III) triflate (2 mol%) in water at 100°C. Different types of aromatic and aliphatic aldehydes are used in the reaction, and in all cases the products synthesized in moderate to excellent yields. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:232–234, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20539     

Fluorescent Detection of 2,4‐DNT and 2,4,6‐TNT in Aqueous Media by Using Simple Water‐Soluble Pyrene Derivatives

Pyrene‐containing water‐soluble probes for the fluorescent detection of nitroaromatic compounds (NACs), such as explosive components (2,4‐DNT and 2,4,6‐TNT) and herbicides (2,4‐dinitrocresol, 2,4‐DNOC), in aqueous media are reported. In the probes, the introduction of surface‐active hydrophilic “heads” at the periphery of lipophilic (i.e., hydrophobic) pyrene “tails” resulted in the formation of highly fluorescent micelle‐like aggregates/pre‐associates in aqueous solutions at concentrations of ≤10^?5 m . The enhanced fluorescence quenching of the herein reported architectures is achieved in the presence of ultra‐trace amounts of TNT or 2,4‐DNT with values of Stern–Volmer quenching constant close to 1×10⁵ m ^?1 and a detection limit as low as 182 ppb. The most hydrophilic probes demonstrated higher response to 2,4‐DNT over TNT. Filter paper test strips impregnated with 1×10^?5 m solutions of the probes were able to detect TNT, 2,4‐DNT, and other NACs at levels as low as 50 ppb in water.     

An efficient synthetic approach towards new 5, 5'-diaryl-2, 2'-bipyridine-based fluorophores

An efficient approach has been developed for the synthesis of 5,5'-diaryl-2,2'-bipyridines via their 1,2,4-triazine analogues. The notable advantages of the present method are:The possibility of varying the aromatic substituents in the positions 5 and 5' of bipyridine core and the possibility for obtaining 2,2'-bipyridines bearing a fused cyclopentene core to increase the solubility in organic solvents. These 5,5'-diaryl-2,2'-bipyridines exhibited an intense emission in a range of ca. 422-521 nm in acetonitrile solution; depending on the nature of the aromatic substituents and the presence of annulated cyclopentene fragments. Apart from that, the significant bathochromic shifts of the both absorption and emission maxima were observed in comparison with a number of previously described similar structures. In some cases the significant increasing of the fluorescence quantum yields took place.