نتایج جستجو برای: ketoester
تعداد نتایج: 79 فیلتر نتایج به سال:
A series of N-substituted 1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate esters has been prepared in two steps from ethyl 2-(2-chloronicotinoyl)acetate. Treatment of the b-ketoester with N,N-dimethylformamide dimethyl acetal in N,N-dimethylformamide (DMF) gave a 95% yield of the 2-dimethylaminomethylene derivative. Subsequent reaction of this b-enaminone with primary amines in DMF at 120C fo...
A convenient method is disclosed for the synthesis of both 3-hydroxyisoquinolines and 2-hydroxy-1,4-naphthoquinones from beta-ketoesters using a one-pot aryne acyl-alkylation/condensation procedure. When performed in conjunction with a one-step method for the synthesis of the beta-ketoester substrates, this method provides a new route to these polyaromatic structures in only two steps from comm...
two simple protocols for the synthesis of three-component condensation reaction of an aldehyde, β-ketoester and urea or thiourea to obtain the 3, 4-dihydropyrimidin-2(1h)-ones (thiones) using nano silica phosphoric acid are reported. short reaction times, high yields, reusability of catalyst and easy workup are some advantages of these protocols.
The title compound, C17H24O5, featuring a 2-carbeth-oxy-3-oxepanone unit in its intra-molecularly O-H⋯O hydrogen-bonded enol form, was obtained via [(CF3CO2)2Rh]2-catal-ysed intra-molecular O-H bond insertion in the α-diazo-ω-hy-droxy-β-ketoester, ethyl 4-[(1S,3aS,6R,6aS)-6-hy-droxy-2,2,3a-trimethyl-3-oxo-octa-hydro-penta-len-1-yl]-2-diazo-3-oxobutano-ate. The seven-membered oxacyclic ring, thu...
The development of (trimethylsilyl)ethyl ester protected enolates is reported. The application of this class of compounds in palladium-catalyzed asymmetric allylic alkylation is explored, yielding a variety of α-quaternary six- and seven-membered ketones and lactams. Independent coupling partner synthesis engenders enhanced allyl substrate scope relative to traditional β-ketoester substrates; h...
We present a general model for understanding the stereochemical course of intramolecular Michael reactions. We show that the addition of β-ketoester enolates to α,β-unsaturated esters and imides bearing adjacent stereocenters (X, Y = H, Me, OR) leads to high levels of asymmetric induction. Reinforcing and nonreinforcing stereochemical relationships are evaluated from the syn and anti reactant d...
decatungstodivanadogermanic acid (h6gew10v2o40.22h2o) was used as a green heterogeneous catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1h)-ones from one-pot three-component cyclocondensation reaction of a β-ketoester, an aldehyde and urea/thiourea under solvent-free conditions is reported. this method provides an efficient and much improved modification of the original biginelli reaction...
An efficient protocol for the synthesis of 3,4-dihydropyrimidin-2-(1H)-one/thione derivatives via multi-component coupling reaction of aromatic aldehydes, β-ketoester and urea or thiourea under solvent-free conditions using Silica Supported Barium Chloride as a catalyst is described. All prepared compounds with melting points, IR,1H NMR and 13C NMR were identified. High yields, mild conditi...
Decatungstodivanadogermanic acid (H6GeW10V2O40.22H2O) was used as a green heterogeneous catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones from one-pot three-component cyclocondensation reaction of a β-ketoester, an aldehyde and urea/thiourea under solvent-free conditions is reported. This method provides an efficient and much improved modification of the original Biginelli reaction...
Decatungstodivanadogermanic acid (H6GeW10V2O40.22H2O) was used as a green heterogeneous catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones from one-pot three-component cyclocondensation reaction of a β-ketoester, an aldehyde and urea/thiourea under solvent-free conditions is reported. This method provides an efficient and much improved modification of the original Biginelli reaction...
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