نتایج جستجو برای: diketone
تعداد نتایج: 518 فیلتر نتایج به سال:
The microelectronics industry is focused on increasing chip complexity, improving the density of electron carriers, and decreasing the dimensions of the interconnects into the sub-0.25 mum regime while maintaining high aspect ratios. Water-based chemical mechanical planarization or polishing (CMP) faces several technical and environmental challenges. Condensed CO2 has significant potential for ...
A convenient heterogeneous continuous-flow procedure for the polarity reversal of aromatic α-diketones is presented. Propaedeutic batch experiments have been initially performed to select the optimal supported base capable to initiate the two electron-transfer process from the carbamoyl anion of the N,N-dimethylformamide (DMF) solvent to the α-diketone and generate the corresponding enediolate ...
A low cost, safe, clean and environmentally benign base-catalyzed cyclodehydration of appropriate β-diketones affording (E)-2-styrylchromones and flavones in good yields is disclosed. Water was used as solvent and the reactions were heated using classical and microwave heating methods, under open and closed vessel conditions. β-Diketones having electron-donating and withdrawing substituents wer...
The CD and UV spectra of (2S)-2,2'-spirobi[2H-benz[e]indene]1,1'(3H,3'H)-dione (2) and (IR,I'S,2S)-I,I',3,3'-tetrahydro-2,2'-spirobi[2H -benz[e]indene]-I,I' -diyl diacetate (3) were theoretical1y calculated by the application of the Jt-electron SCF-CI-DV MO method. The shape of component CD and UV bands was approximated by method (A) of the Gaussian distribution, or by method (B) employing the ...
From quantum mechanics calculations we confirm that the naturally occurring enol lancifodilactone G is stable over the keto form (by 2.6 kcal/mol in water), the only known stable aliphatic enol (devoid of conjugated or bulky aromatics and lacking a 1,3-diketone structural motif known to stabilize enols). We determine architectural elements responsible for the enol stabilization and find a mecha...
We describe a new synthesis of the 3-chloro-(4'-methoxy)-2,2'-pyrrolylfuran segment (3) of (+)- roseophilin. The route exploits a isoxazoylpyrrole intermediate, wherein the isoxazole ring serves as a β-diketone equivalent and a directing group for palladium catalyzed chlorination of the attached pyrrole. Subsequent reduction of the N-O bond and acid promoted cyclization afords roseophilin segme...
SYNLETT 2010, No. 11, pp 1712–1716xx.xx.2010 Advanced online publication: 14.06.2010 DOI: 10.1055/s-0030-1258094; Art ID: Y00510ST © Georg Thieme Verlag Stuttgart · New York Abstract: The use of high-throughput screening allowed for the optimization of reaction conditions for the palladium-catalyzed asymmetric decarboxylative alkylation reaction of enolate-stabilized enol carbonates. Changing t...
A new strategy was developed to synthesize 1,2-disubstituted 4-quinolones in good yield starting from 1,3-bisaryl-monothio-1,3-diketone substrates. The synthesized compounds were evaluated for antimalarial activity using Plasmodium falciparum strains. All compounds, except for two, showed good activity. Of these, seven compounds exhibited an excellent antimalarial activity (IC50, <2 μM). More i...
An efficient method for the N-heterocyclic carbene (NHC)-catalyzed conjugate addition of acetyl anions to various α,β-unsaturated acceptors (Stetter reaction) has been optimized by using 2,3-butandione (biacetyl) as an alternative surrogate of acetaldehyde. The disclosed procedure proved to be compatible with microwave dielectric heating for reaction time reduction and with the use of different...
We describe complexes of ruthenium and europium with rigid, 5'-6-locked 1,10-phenanthroline-containing nucleosides. Both nucleosides were synthesized from condensation of 5-amino-2'-deoxycytidine with the corresponding diketone. The ruthenium nucleoside displayed fluorescence characteristic of polypyridine ruthenium complexes with a maximum at 616 nm and a quantum yield of 0.011. Binding of eur...
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