RESUMEN
Chemically modified chitosan namely epichlorohydrin cross-linked xanthate chitosan (ECXCs) has been used for the removal of Cu(II) ions from aqueous medium. The influence of various operating parameters such as pH, temperature, sorbent dosage, initial concentration of Cu(II) ions and contact time on the adsorption capacity of ECXCs has been investigated. Thermodynamic parameters namely Delta G degrees, Delta H degrees and DeltaS degrees of the Cu(II) adsorption process have been calculated. Differential anodic stripping voltammetric technique was used to determine the concentration of Cu(II) in the test solution before and after adsorption. The nature of the possible adsorbent-metal ion interactions was studied by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The studies showed that the adsorption of Cu(II) on ECXCs strongly depends on pH and temperature. The maximum adsorption capacity was observed at pH 5.0 and the adsorption capacity of ECXCs increased with increasing temperature indicating the endothermic nature of adsorption process. Langmuir and Freundlich adsorption equations were used to fit the experimental data. The adsorption process is found to follow the pseudo-second-order kinetic model. The maximum adsorption capacity was found to be 43.47 mg g(-1) from the Langmuir isotherm model at 50 degrees C. During desorption studies 97-100% of adsorbed copper ion is released into solution in presence of 1N EDTA, HCl and H(2)SO(4).
Asunto(s)
Quitosano/química , Cobre/química , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , Agua/química , Adsorción , Epiclorhidrina/química , Concentración de Iones de Hidrógeno , Iones , Cinética , Espectroscopía de Resonancia Magnética , Espectroscopía de Fotoelectrones/métodos , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Termodinámica , Contaminantes Químicos del Agua/aislamiento & purificaciónRESUMEN
A new class of C8-linked pyrrolo[2,1-c][1,4]benzodiazepine-chalcone conjugates have been prepared by employing a solid-phase synthetic protocol. In this strategy an intramolecular aza-Wittig reductive cyclization approach has been utilized. Interestingly, some of these molecules have shown enhanced DNA-binding affinity and promising anticancer activity on a large number of human cancer cell lines.
Asunto(s)
Antineoplásicos/farmacología , Benzodiazepinas/farmacología , Línea Celular Tumoral/efectos de los fármacos , Chalcona/farmacología , ADN/metabolismo , Pirroles/farmacología , Antineoplásicos/síntesis química , Benzodiazepinas/síntesis química , Sitios de Unión , Chalcona/análogos & derivados , Chalcona/síntesis química , ADN/química , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Modelos Químicos , Pirroles/síntesis química , Relación Estructura-ActividadRESUMEN
A versatile method for the solid-phase synthesis of imidazo[1,2-a]pyridine-based derivatives, imidazo[1,2-a]pyridine-8-carboxamides, has been developed. They were obtained by treatment of the amino group of the polymer-bound 2-aminonicotinate with different alpha-haloketones, followed by halogenation at the 3-position of the polymer-bound imidazo[1,2-a]pyridine. The derived polymer-bound imidazo[1,2-a]pyridines 5, 6, and 7 were finally cleaved from the solid-support with an excess of primary or secondary amines. The final crude products were purified from excess amines by solid-supported liquid-liquid extraction (SLE).
Asunto(s)
Amidas/síntesis química , Piridinas/química , Amidas/química , Espectroscopía de Resonancia Magnética , Espectrometría de Masa por Ionización de Electrospray , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
A versatile combinatorial approach was developed and utilized for the rapid synthesis of pyrrolo[2,1-c]-[1,4]benzodiazepine-5,11-dione (PBD-5,11-dione) libraries 10, 15, and 19 containing 210 compounds with varied substitutions in A, B, and C rings. The key aspect of the synthetic strategy includes Staudinger, intermolecular aza-Wittig reaction followed by imine reduction and base-mediated cyclative cleavage results in the formation of final resin-free compounds. This strategy provides a highly efficient and practical protocol for the parallel synthesis of PBD-5,11-diones on solid support. The modifications in the C-ring of the PBD scaffold produced three types of sublibraries. Reactions were monitored by FT-IR spectroscopy on the resin beads. Further, from a generated library of 210 compounds, 142 compounds have been selected and evaluated for in vitro activity against Mycobacterium tuberculosis, and some of these compounds have exhibited promising activity.
Asunto(s)
Antituberculosos/síntesis química , Benzodiazepinonas/síntesis química , Benzodiazepinonas/farmacología , Pirroles/síntesis química , Pirroles/farmacología , Antituberculosos/farmacología , Técnicas Químicas Combinatorias/métodos , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/efectos de los fármacos , Prolina/química , Espectrometría de Masa por Ionización de Electrospray , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Benzodiazepine based heterocycles can be prepared efficiently on solid-support by employing different approaches. In this review, an effort has been made to highlight academic and industrial examples of combinatorial synthesis for this type of heterocycles published in the last decade. Therefore, it describes synthetic strategies for the generation of benzodiazepine privileged structures employing the corresponding resin-bound substrates. Further, the most relevant biological properties of these heterocycles have also been incorporated.
Asunto(s)
Benzodiazepinas/síntesis química , Técnicas Químicas Combinatorias/métodos , Alcaloides/síntesis química , Benzodiazepinas/química , Benzodiazepinonas/síntesis química , Benzodiazepinonas/química , Estructura Molecular , Pirroles/química , Triazoles/síntesis químicaRESUMEN
Quinoxaline, quinazoline and benzimidazole based templates have been synthesized on solid-support employing different methodologies. This review enlightens academic and industrial examples of combinatorial synthesis for this type of heterocycles that appeared in the literature in the last decade. Hence, some of the important synthetic strategies for the generation of quinoxaline, quinazoline and benzimidazole based privileged structures, and the important biological activities for these heterocycles have been highlighted. Further, benzothiadiazinone, thioxoquinazolinone, cinnoline and indazole are also examined in this review.
Asunto(s)
Bencimidazoles/síntesis química , Técnicas Químicas Combinatorias/métodos , Quinazolinas/síntesis química , Quinoxalinas/síntesis química , Bencimidazoles/química , Benzotiadiazinas/síntesis química , Compuestos Heterocíclicos con 2 Anillos/química , Indazoles/síntesis química , Estructura Molecular , Ftalazinas/síntesis química , Piranos/síntesis químicaRESUMEN
Fluoroquinolones have been synthesized and linked to DC-81 at C8 position through different alkyl chain spacers. These PBD conjugates have exhibited good DNA binding affinity, and a representative compound shows promising in vitro anticancer activity.