A Solvent-free Synthesis of Polyhydroquinolines via Hantzsch Multicomponent Condensation Catalyzed by Nanomagnetic-supported Sulfonic Acid

A simple and efficient procedure for the synthesis of polyhydroquinolines was developed, involving a one-pot four-component Hantzsch condensation of aromatic aldehydes, 1,3-cyclohexanediones, alkyl acetoacetate and ammonium acetate in the presence of a catalytic amount of nanomagnetic-supported sulfonic acid under solvent-free conditions. The method offers several advantages including high yields, short reaction times, a simple work-up procedure and catalyst reusability for several runs. Furthermore, easy isolation of the catalyst from the reaction mixture was enabled by use of an external magnet.KEYWORDS Nanomagnetic-supported sulfonic acid, multicomponent reaction, solvent-free conditions, heterocyclic compound, Hantzsch reaction

Green SDS-assisted synthesis of quinoxaline derivatives in the water

A simple, practical and convenient procedure for the synthesis of quinoxaline derivatives has been developed by reaction of 1,2-phenylenediamines with 1,2-diketones in the presence of sodium dodecyl sulfate (SDS) in the aqueous medium at room temperature without any organic solvent

Nano perlite sulfuric acid: an inexpensive heterogeneous acid catalyst for the synthesis of 1,8-dioxo-octahydroxanthenes and tetrahydrobenzoxanthenes under solvent-free conditions

Nano perlite sulfuric acid (n-PeSA) as an inexpensive powerful solid acid nanocatalyst has been successfully applied for the efficient and green synthesis of 1,8-dioxo-octahydroxanthenes and tetrahydrobenzoxanthenes under solvent free condition in excellent yield. These new procedures offer many advantages including ease of preparation and handling, low cost and low toxicity of catalyst, environmental friendliness reaction conditions, short reaction time and absence of any tedious workup or purification .Furthermore, the catalyst could be recycled and reused at least five times without appreciable deterioration in catalytic activity, confirming the stability of the covalent bonding of acidic centers

Use of pyridinium ionic liquids as catalysts for the synthesis of 3,5-bis(dodecyloxycarbonyl)-1,4-dihydropyridine derivative

The synthesis of cationic amphiphilic 1,4-dihydropyridine derivative, potential gene delivery agent is achieved via an efficient multi-step sequence. The key step of this approach is a two-component Hantzsch type cyclisation of 3-oxo-2-[1-phenylmethylidene]-butyric acid dodecyl ester and 3-amino-but-2-enoic acid dodecyl ester utilising bis(2-hydroxyethyl)ether as a solvent and 1-butyl-4-methylpyridinium chloride as a catalyst. The 1,4-dihydropyridine derivative with long alkyl ester chains at positions 3 and 5 of the 1,4-DHP ring - 3,5-bis(dodecyloxycarbonyl)-2,6-dimethyl-4-phenyl-1,4-dihydropyridine was obtained in substantially higher yield with respect to classical Hantzsch synthesis. Bromination of this compound followed by nucleophilic substitution of bromine with pyridine gave the desired cationic amphiphilic 1,4-dihydropyridine.publishersversionPeer reviewe

Adsorptive removal of ciprofloxacin and isoniazid from aqueous solution

This paper describes study of ciprofloxacin and isoniazid removal from aqueous solutions using coal fly ash (FA), kaolinite, perlite, talc and vermiculite. The adsorptive features of the adsorbents were evaluated for ciprofloxacin and isoniazid with regards to the effects of contact time, pH, the solid/liquid ratio and antibiotic concentration. All adsorbents were sterilised by dry heat before use to avoid the proliferation of antimicrobial resistance by the bacteria present on the adsorbents during experiments. The regression correlation coefficients indicate that the Langmuir model gives the best fit for the sorption of both antibiotics onto FA and talc, ciprofloxacin onto kaolinite, and isoniazid onto perlite and vermiculite with R2 values ranging from 0.908 – 0.999. The Freundlich isotherm best describes the sorption of ciprofloxacin onto vermiculite and isoniazid onto kaolinite with R2 values of 0.999 for both. The Tempkin model best describes the sorption of ciprofloxacin onto perlite with an R2 = 0.997. The values of the Freundlich exponent, 1/n, range from 0.221 – 0.998, indicating a favourable adsorption of ciprofloxacin and isoniazid onto the adsorbents. The heat of sorption, B, calculated from the Temkin plots has values ranging from 0.018 – 10.460 J/mol, indicating a physical adsorption process (physisorption). Adsorption equilibrium was achieved after 30 min for both antibiotics and the kinetic data obtained conforms best to the pseudo-second order equation with R2 values ranging from 0.998 – 0.999. The removal of ciprofloxacin and isoniazid by all adsorbents except FA was strongly influenced by the pH suggesting that electrostatic interactions play a major role in the adsorption processes