Ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br): a green and neutral reaction media for the efficient, catalyst-free synthesis of quinoxaline derivatives

Quinoxaline derivatives were produced in excellent yields and short reaction times via the condensation of 1,2-diamines with 1,2-diketones in the neutral ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) under catalyst-free and microwave irradiation conditions

Green Three-component One-pot Synthesis of Benzo[b]pyran and Pyrano[c]chromene Derivatives Using Nanosilica-supported Dendritic Polymer Encapsulated Phosphotungstic acid (Dendrimer-PWAn) Nanoparticles in Aqueous Media under Ultrasound Irradiation

An efficient and green approach was developed for the synthesis of various derivatives of tetrahydrobenzo[b]pyran and 3,4-dihydropyrano[c]chromene in the presence of Dendrimer-PWAn as nanocatalyst at ambient temperature through a one-pot three-component reaction between aromatic aldehydes, malononitrile, and dimedone or 4-hydroxycoumarin in an aqueous media under ultrasound irradiation. In order to prepare this catalyst, H3PW12O40 (PWAn) nanoparticles provided by a solvo-thermal method were encapsulated into dendritic polymer-supported on nanosilica. The catalyst is mesoporous and has a particle size of 40 nm. The mean pore diameter, BET surface area and pore volume are 6.1 nm, 479 m2/g and 0.6 cm3, respectively. The amounts of PWAn immobilized on the nanocatalyst was found to be 39.7 wt% (0.14 mmol/g). The developed method is not only suitable for aromatic aldehydes but also successfully used for acid sensitive heteroaromatic aldehydes, and the corresponding products were synthesized with high purity in high yield, and short reaction times. This new method has significant advantages such as operational simplicity, high efficiency, short reaction time and lack of elaborate workup or tedious purification procedures. In addition, excellent yields in a mild environment, thermal stability, and simple catalyst separation make it a suitable alternative to other heterogeneous catalysts. Also, this catalyst can be easily recycled through simple filtration or centrifugation and used for six consecutive periods without significant reduction in activity

A simple indicator displacement assay ensemble for rapid and selective determination and naked-eye detection of Cu²⁺ and citrate through a novel diazo-based colorimetric chemosensor

Citrate as a naturally occurring ion with important biological roles, especially in metabolic cycles, and as an important biomarker in the early diagnosis of many diseases, including prostate cancer, has received special attention. In the present study, a novel, sensitive, fast and simple colorimetric bisazo-based chemosensor was developed for sequential determination and naked-eye detection of Cu2+ and citrate. UV-Vis spectroscopic studies showed that Reactive Red 141 (RR141) exhibits high selectivity and sensitivity towards Cu2+ in the presence of many other cations in deionised water (10 mmol L−1 MES(2-(N-morpholino)ethanesulfonic acid)/NaOH buffer solution, pH 6.0) and complex real samples as well. The obvious colorimetric response while interaction with copper and citrate is due to complexation between RR141 and Cu2+, and then the citrate detection occurred through metal transfer from the RR141-Cu2+ towards the citrate anion releasing RR141 via an indicator displacement route. The mechanism of detection has been carefully investigated using the semi-empirical calculation method of MM2 molecular mechanics. The proposed detection method for citrate ion has a detection limit of 0.15 µmol L−1 and a satisfactory linear range of 1.92–45.96 µmol L−1, which is consistent with the desired average diagnostic concentration in prostate cancer (less than 2 mmol L−1). Our studies’ results indicate the high capability of the developed chemical sensor for quantitative and qualitative citrate detection in various complex media, including biological and clinical real samples.</p

ChemInform Abstract: One-Pot Synthesis of N-Alkyl Purine and Pyrimidine Derivatives from Alcohols Using TsIm: A Rapid Entry into Carboacyclic Nucleoside Synthesis.

A convenient and efficient one-pot N-alkylation of nucleobases from alcohols using N-( p-toluenesulfonyl)imidazole (TsIm) is described. In this method, treatment of alcohols with a mixture of purine or pyrimidine nucleobase, TsIm, K 2CO 3, and triethylamine in refluxing DMF regioselectively furnishes the corresponding N-alkyl nucleobases in good yields. This methodology is highly efficient for various structurally diverse primary alcohols. [Display omitted

JSCS–4054 Original scientific paper

Ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br): a green and neutral reaction media for the efficient, catalyst-free synthesis of quinoxaline derivative