نتایج جستجو برای: dbu
تعداد نتایج: 315 فیلتر نتایج به سال:
A practical Pd(PPh(3))(4)/DBU catalytic system for the synthesis of pharmaceutically relevant aminopyridine nitrile intermediates, as well as a variety of other aryl nitriles using non-toxic K(4)[Fe(CN)(6)] has been developed. The key features of our new protocol for cyanation lie in that the reaction can be carried out with readily available Pd(PPh(3))(4) under mild and green conditions, even ...
The amidine organocatalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is an effective nucleophilic catalyst. Biocomposites with tuneable properties were successfully synthesized by ring-opening graft polymerization (ROGP) of propylene carbonate (PC) onto xylan using DBU as a catalyst in the ionic liquid (IL) 1-allyl-3-methylimidazolium chloride ([Amim]Cl). The effects of reaction temperature, rea...
The effects of endothelin-1 (ET-1) on the production of plasminogen activator inhibitor 1 (PAI-1) and tissue plasminogen activator (t-PA) by human brain-derived endothelial cells in culture were studied. At 100 nmol/L, ET-1 increased PAI-1 production by 88+/-6% within 72 hours, and increased PAI-1 mRNA expression within 1 hour of stimulation; there was no significant effect on t-PA production. ...
The Front Cover illustrates the ability of DBU – yellow tightrope walker to preserve fluoride nucleophilicity promoting fluorination a pentafluoroisobutenyl group five-flower bouquet carried by young lady in cascade reaction. In contrast, alkali metals blue acrobats precipitate with ions precluding subsequent hydrofluorination. created Ludion. More information can be found Research Article G. G...
Efficient conversion of glucose to 5-hydroxymethylfurfural (HMF), an important platform molecular for fuels and chemicals, is a promising topic in green chemistry. In this work, several new DBU-based (DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene) ionic liquids (ILs) with benzene sulfonate (BS) anion were synthesized and used as the solvents for the dehydration of glucose to HMF. It was found that a...
1-alkyl aryl-5-amino-4-(cyanoformimidoyl)imidazoles 4 were reacted with malononitrile and 2-amino-1,1,3-propenetricarbonitrile under mild experimental conditions, which led to 5-amino-3-(substituted benzyl)-6,7-dicyano-3H-imidazo[4,5-b]pyridines 5 and 6,8-diamino-3-(4-substituted benzyl)-3H-imidazo[4,5-b]-1,8-naphthyridine-7,9-dicarbonitrile 6, respectively, when the reaction was carried out in...
An efficient synthesis of the N-methylwelwistatin tetracyclic core in only two steps from Kornfeld's ketone is described, whose key transformation involves the generation of a fused bicyclo[4.3.1]decane ring system through a one-pot sequence comprising a Michael-intramolecular aldolization anionic domino process and a DBU-promoted hydrolysis of the N-pivaloyl protecting group. Besides providing...
A novel metal-free organobase-catalyzed regioselective benzoylation of diols and carbohydrates has been developed. Treatment of diol and carbohydrate substrates with 1.1 equiv. of 1-benzoylimidazole and 0.2 equiv. of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in MeCN under mild conditions resulted in highly regioselective benzoylation for the primary hydroxyl group. Importantly, compared to most ...
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