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حرية الوصول المقاله
1 - Tungstophosphoric acid embedded magnetic chitosan as a green catalyst for the synthesis of N-cyclohexyl-3-aryl quinoxaline-2-amines
Ali Ayati Mansoureh Daraie Majid Heravi Bahareh TanhaeiIn the present study, a novel catalyst was well designed by incorporating the tungstophosphoric acid into the magnetic chitosan, as highly stable composite, in which the iron oxides were used the strong super-magnetic core. The prepared composite was characterized by se أکثرIn the present study, a novel catalyst was well designed by incorporating the tungstophosphoric acid into the magnetic chitosan, as highly stable composite, in which the iron oxides were used the strong super-magnetic core. The prepared composite was characterized by several methods, including FTIR, XRD, SEM, TEM and EDS and its catalytic activity was examined in a facile, green and highly efficient one-pot reaction for the synthesis of N-cyclohexyl-3-aryl-quinoxaline-2-amines with o-phenylenediamine, benzaldehyde and cyclohexyl isocyanide in water, under reflux conditions. This heterogeneous catalytic system was separated easily by an external magnet and was reused at least in four runs without pre-activation and appreciable loss in its activity. تفاصيل المقالة -
حرية الوصول المقاله
2 - Synthesis of 1,3-diphenyl-2-propyn-1-ol derivatives in water catalyzed by silver ions immobilized on the magnetic cross-linked chitosan
Fatemeh Rafiee Sahar KermaniIn this work, chitosan biopolymer was cross-linked by starch oxide through the covalent bond formation between amine groups of chitosan and aldehyde functional of oxidized starch. A magnetic bio-support was obtained due to the treatment of the produced hybrid biopolymer أکثرIn this work, chitosan biopolymer was cross-linked by starch oxide through the covalent bond formation between amine groups of chitosan and aldehyde functional of oxidized starch. A magnetic bio-support was obtained due to the treatment of the produced hybrid biopolymer with iron oxide nanoparticles. As a result of exposing of silver nitrate salt to magnetic polymer, silver ions (Ag2O) and also Ag metal nanoparticles were deposited on this bio-support. The silver oxide was decorated on the magnetic chitosan biopolymer could catalyzed the cross-coupling reaction of substituted benzaldehydes with phenylacetylene in the presence of PPh3 (20 mol%) in water to achieve 1,3-diphenyl-2-propyn-1-ol derivatives in good yields at proper reaction times. تفاصيل المقالة