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Acetophenone Derivatives (acetophenone + derivative)
Selected AbstractsLithiation of 2-(Chloroaryl)-2-methyl-1,3-dioxolanes and Application in Synthesis of New ortho-Functionalized Acetophenone Derivatives.CHEMINFORM, Issue 29 2003Gyula Lukacs Abstract For Abstract see ChemInform Abstract in Full Text. [source] 13C and 1H nuclear magnetic resonance of methyl-substituted acetophenones and methyl benzoates: steric hindrance and inhibited conjugationMAGNETIC RESONANCE IN CHEMISTRY, Issue 10 2004ínský Abstract The 1H and 13C NMR spectra of 14 methyl-substituted acetophenones and 14 methyl-substituted methyl benzoates were assigned and interpreted with respect to the conformation of the Car,C(O) bond. The substituent effects are proportional in the two series and can be divided into polar and steric: each has different effects on the 13C SCS of the individual atoms. In the case of C atoms C(O), C(1) and CH3(CO), the steric effects were quantitatively separated by comparing SCS in the ortho and para positions. The steric effects are proportional for the individual C atoms and also to steric effects estimated from other physical quantities. However, they do not depend simply on the angle of torsion , of the functional group as anticipated hitherto. A better description distinguishes two classes of compounds: sterically not hindered or slightly hindered planar molecules and strongly sterically hindered, markedly non-planar. In order to confirm this reasoning without empirical correlations, the J(C,C) coupling constants were measured for three acetophenone derivatives labeled with 13C in the acetyl methyl group. The constants confirm unambiguously the conformation of 2-methylacetophenone; their zero values are in accord with the conformation of 2,6-dimethylacetophenone. The zero values in the unsubstituted acetophenone are at variance with previous erroneous report but all J(C,C) values are in accord with calculations at the B3LYP/6-311++G(2d,2p)//B3LYP/6,311+G(d,p) level. Copyright © 2004 John Wiley & Sons, Ltd. [source] New chiral phosphinite ligands with C2 -symmetric axis and their possible applications in Ru-catalyzed asymmetric transfer hydrogenationAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2010Murat Aydemir Abstract The new chiral ligands N,N,-bis-[(1R)-1-ethyl-2- O -(diphenylphosphinite)ethyl]ethanediamide, 1, and N,N,-bis-[(1S)-1-isobutyl-2- O -(diphenylphosphinite)ethyl]ethanediamide, 2, and the corresponding ruthenium complexes 3 and 4 were prepared and their structures were elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy and elemental analysis. Following activation by NaOH, these chiral ruthenium complexes serve as catalyst precursors for the asymmetric transfer hydrogenation of acetophenone derivatives in iPrOH. The complexes 3 and 4 showed high catalytic activity but low selectivity in asymmetric transfer hydrogenation reactions. Copyright © 2009 John Wiley & Sons, Ltd. [source] Synthesis of novel rhodium-xylyl linked N -heterocyclic carbene complexes as hydrosilylation catalystsAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 1 2008Ismail Özdemir Abstract Reaction of ortho -xylylbis(N -2,4,6-trimethylbenzylimidazolinium); xylylbis(N -butylimidazolinium) and para -xylylbis(N -2,4,6-trimethylbenzylimidazolinium); xylylbis(N -butylimidazolinium) salts with KOBut and [RhCl(COD)]2 yields ortho - and para -xylylbis{(N -alkylimidazolidin-2-ylidene)chloro(,4 -1,5-cyclooctadiene) rho dium(I)} complexes (2a,d). All compounds synthesized were characterized by elemental analysis and NMR spectroscopy, and the molecular structures of the 2a and 2d were determined by X-ray crystallography. Triethylsilane reacts with acetophenone derivatives in the presence of catalytic amount of the new rhodium(I),carbene complexes (2a,d), to give the corresponding silylethers in good yields (83,99%). Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||