- Stability or flexibility: Metal nanoparticles supported over cross-linked functional polymers as catalytic active sites for hydrogenation and carbonylation
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A novel cross-linked functional polymer was prepared through copolymerization between 1, 3, 4, 6-tetraallylglycoluril and 4-vinyl pyridine. Pt and Pd nanoparticles supported over this polymeric framework (Pt/CFP and Pd/CFP) were detailedly characterized by TEM, EDS, and XPS. Pt nanoparticles were kept in the monodispersed state with the average size of 1.4 nm. Monodispersed Pd nanoparticles were about 4.5 nm. The hydrogenation of nitrobenzenes over Pt/CFP shows high activity and selectivity with the substrate to Pt ratio of 4000 under mild reactions. Pd/CFP was the catalyst for carbonylation of aryl iodides in the presence of secondary amines and acylhydrazines. Double carbonylation with secondary amines produced α-ketoamides with the selectivity of 80%. Diacylhydrazine molecules were synthesized by the direct carbonylation of aryl iodide with acylhydrazine over Pd/CFP. The recyclability and recoverability of Pt/CFP were investigated through a seven-run recycling test of nitrobenzene hydrogenation. The flexibility of Pd/CFP in the carbonylation process was thoroughly explored by a 12-run recycling test. Supported Pt or Pd nanoparticles showed the macroscopic robustness in their catalytic performance in the catalytic cycle. The flexibility of metal nanoparticles and the polymeric supports guaranteed macroscopic catalytic robustness.
- Chen, Bingfeng,Li, Fengbo,Huang, Zhijun,Lu, Tao,Yuan, Guoqing
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- Mild and convenient one-pot synthesis of 1,3,4-oxadiazoles
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A mild, general, convenient, and efficient one-pot synthesis of 2-phenyl-5-substituted-1,3,4-oxadiazoles is described. Both (hetero)aryl and alkyl carboxylic acids were efficiently condensed with benzohydrazide in the presence of TBTU to give diacylhydrazine intermediates. The latter underwent a smooth TsCl-mediated cyclodehydration reaction to afford 2-phenyl-5-substituted- 1,3,4-oxadiazoles in good to very good yields.
- Stabile, Paolo,Lamonica, Alessandro,Ribecai, Arianna,Castoldi, Damiano,Guercio, Giuseppe,Curcuruto, Ornella
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supporting information; experimental part
p. 4801 - 4805
(2010/10/02)
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- Facile synthesis and stracture of novel 2,5-disubstituted 1,3,4-selenadiazoles
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The reaction of hydrazide with carbony] chloride in the presence of sodium carbonates leads to the corresponding 1,2- diacylhydrazines [1a-t, R 1C(O)NHNHC(O)R2, R1 = aryl, R2 = aryl or alkyl] in moderate to excellent yield (57-90%). The latter reacts with 2,4-diphenyl-l,3-diselenadiphosphetane- 2,4-diselenide (Woollins' reagent, WR) in refluxing toluene to give a series of new 2,5-disubstituted 1,3,4-selenadiazoles (2a-t, 51-99% yield). All compounds were characterized spectroscopically and six compounds were characterized crystalloqraphically. Wiley-VCH Verlag GmbH & Co. KGaA.
- Hua, Guoxiong,Li, Yang,Fuller, Amy L.,Slawin, Alexandra M.Z.,Woollins, J. Derek
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experimental part
p. 1612 - 1618
(2009/08/09)
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- 1,3,4-Oxadiazole formation as traceless release in solid phase organic synthesis
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Oxadiazoles were generated upon a dehydrative cyclization reaction with 2-acyl hydrazides bound to the polymeric support via one of their N atoms using TFAA as a dehydration agent.
- Cesarini, Sara,Colombo, Nicoletta,Pulici, Maurizio,Felder, Eduard R.,Brill, Wolfgang K.-D.
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p. 10223 - 10236
(2007/10/03)
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- Piperazine compounds as inhibitors of MMP or TNF
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A compound of formula (I) wherein A is a sulfonyl or a carbonyl; R1is an optionally substituted aryl, an optionally substituted heterocyclic group, an optionally substituted lower alkyl or an optionally substituted lower alkenyl; R2is a hydrogen, an optionally substituted lower alkyl, an optionally substituted aryl or an optionally substituted heterocyclic group; R3is an optionally substituted lower alkyl, an optionally substituted lower alkoxy, an optionally substituted aryloxy, an optionally substitued lower alkenyl, an optionally substituted aryl, an optionally substituted heterocyclic group or an optionally substitued amino; R4is a hydrogen, an optionally substituted lower alkyl, an optionally substituted aryl or an optionally substituted heterocyclic group; R5is a hydrogen, an optionally substituted lower alkyl, an optionally substituted aryl or an optionally substituted heterocyclic group; and R10is a hydroxy or a protected hydroxy, and a pharmaceutically acceptable salt thereof. The compound of the present invention is useful as a medicament for prophylactic and therapeutic treatment of MMP- or TNFα-mediated diseases.
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