نتایج جستجو برای: 18 diazabicyclo540 undec 7 ene dbu hydrobromide perbromide
تعداد نتایج: 931924 فیلتر نتایج به سال:
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 ...
3,5-disubstituted-2,6-dicyanoaniline derivatives have been synthesized via the reaction of aryl methylene- and 1-arylethylidenemalonodinitriles using 1,8-diazabicyclo[5.4.0] undec-7-ene (dbu) as a novel and highly efficient catalyst under conventional as well as microwave conditions. use of non-hazardous, inexpensive and readily available base catalyst, convenient procedure, short reaction tim...
Depending on the catalyst used, N-methylation of indole with dimethylcarbonate (DMC)—an environmentally friendly alkylation agent—yields different products. With 1,4-diazabicyclo[2.2.2]octane (DABCO), reaction forms only N-methylated indole, but 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), both and N-methoxycarbonylated are formed. Using direct ESI(+)-MS monitoring to collect actual snapshots chan...
The ethoxycarbonylmethyl esters of 1,4-dihydropyridines were directly converted into carbamoylmethyl esters in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) in good to excellent yields under mild conditions. The use of TBD is crucial for the successful aminolysis of ethoxycarbonylmethyl ester of 1,4-dihydropyridines with secondary amines as without it the reaction does not proceed a...
The catalytic activity of 1,8-diazabicyclo [5,4,0]undec-7-ene-intercalated α-zirconium phosphates (α-ZrP·DBU) as thermal latent catalysts in the reaction hexamethylene diisocyanate (HDI) and phenol was investigated. α-ZrP intercalation compounds with varying amounts DBU (α-ZrP·xDBU, where x = 0.58, 0.44, 0.22, 0.10) were prepared. HDI α-ZrP·DBU carried out at temperatures for 30 min periods. sh...
3,5-disubstituted-2,6-dicyanoaniline derivatives have been synthesized via the reaction of aryl methylene- and 1-arylethylidenemalonodinitriles using 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) as ...
We report the direct incorporation of hexafluoroisobutyl group on a chiral glycine Schiff base complex mediated by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The fluoroalkylation involves 2-(bromomethyl)-1,1,1,3,3,3-hexafluoropropane reagent, which generates in situ hexafluoroisobutylene (HFIB), and reacts then with enolate through tandem allylic shift/hydrofluorination process. showed that use ...
a series of 2-amino-4-(nitroalkyl)-4h-chromene-3-carbonitriles were synthesized by an efficient multicomponent reaction in aqueous media using dbu (1,8-diazabicyclo[5.4.0]undec-7-ene) as a catalyst at room temperature. mild condition, environment friendly procedure and excellent yields are the main advantages of this procedure. the cytotoxic activity of target compounds were evaluated against t...
A single clean, good-yielding, environment-friendly microwave-assisted procedure for O-silylation of uridine with tert-butyldimethylsilyl chloride (TBDMSCl), 1,8-Diazabicyclo(5.4.0)undec-7-ene (DBU) and potassium nitrate as catalyst under solvent-free conditions is reported. Subsequent silyl ether deprotection accomplished a reusable acidic resin via microwave irradiation. Both the silylation d...
A series of 2-amino-4-(nitroalkyl)-4H-chromene-3-carbonitriles were synthesized by an efficient multicomponent reaction in aqueous media using DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) as a catalyst at room temperature. Mild condition, environment friendly procedure and excellent yields are the main advantages of this procedure. The cytotoxic activity of target compounds were evaluated against t...
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