Use of tris-(dipivalomethanato)europium as a shift reagent in the identification of 3-H-pyrano[3,2-f]quinolin-3-one

Synthesis Through Three‐Component Reactions Catalyzed by FeCl3 of Fused Pyridocoumarins as Inhibitors of Lipid Peroxidation

“…Construction of the pyridine moiety involves the iodocyclization of 6‐(but‐2‐ynyl)aminocoumarin in the presence of I 2 , developed by Majumdar et al . ; the Pd‐catalyzed Heck cyclization of (2′‐bromo)benzylaminocoumarins to dihydropyrido[3,2‐ g ]‐ or [2,3‐ c ]coumarins, the Skraup reaction on 6‐nitrocoumarin, the reactions of aminocoumarins with glycerol, malondialdehyde, ethyl benzoylacetate, alkyl vinyl ketones or under Vilsmeier conditions, the Diels–Alder reactions of the O ‐methyl imine of 2‐oxo‐2 H ‐chromene‐4‐carboxaldehyde with dienophiles, and reactions of 4‐oxo‐4 H ‐chromene‐3‐carbaldehyde with enamines. Very recently, the synthesis of pyridine skeleton was obtained in the presence of BF 3 .Et 2 O through aza‐Claisen rearrangement followed by in situ cyclization of propargylaminocoumarins under microwave irradiation or via three‐component domino reaction from aminocoumarin, benzaldehyde, and phenylacetylene.…”

“…The synthesis of pyridocoumarins has been achieved either by formation of the pyridine or the pyranone moieties. Construction of the pyridine moiety involves the iodocyclization of 6‐(but‐2‐ynyl)aminocoumarin in the presence of I 2 , developed by Majumdar et al .…”

Lanthanide shift reagents. Survey

“…Soc., 91, 5160 (1969). riety of functional organic molecules including alcohols,113-5'7-9•15'16•18 amines,3,1°•13,15,18 ketones, 3,11,14,18 aldehydes,318 sulfoxides,6•17 and esters; 12,13,16,18119 (2) the observation3 that Eu(dpm)8 is more efficient in effecting such shifts than is Eu(dpm)8(py)2, presumably owing to the lack of competition with pyridine for coordination sites; (3) the discovery4 that Pr(dpm)3 causes upfield shifts of larger magnitude than the downfield displacements induced by Eu(dpm)3 and the observa-tion13 of shifts for substrates in the presence of dpm complexes of Sm, Tb, Ho, and Yb as well; (4) the in-troduction10 of the chiral chelate, tris[(+)-3-pivaloylcamphorato]europium(III), a shift reagent for the determination of enantiomeric purity; (5) the observation that certain other lanthanide complexes4 as well as ß-diketonate chelates with less bulky substituents18,21 than Ln(dpm)3 are inefficient as shift reagents, very likely owing to the lack of a preferred orientation of the substrate molecule when the stereochemical rigidity and the bulky substituents of the chelate rings are absent; (6) the finding19 that partially fluorinated chelates of a similar variety are superior shift reagents because of propitious solubility and Lewis acidity characteristics.…”

Lanthanide shift reagents. X-ray structure of the eight-coordinate bis(4-picoline) adduct of 2,2,6,6-tetramethylheptane-3,5-dionatoholmium, Ho(dpm)3(4-pic)2

“…The Pennsylvania State University University Park, Pennsylvania 16802 Received June 14,1971 Use of Tetrakis(trifluorophosphine)nickel as a Source of Trifluorophosphine in the Synthesis of Metal-Trifíuorophosphlne Complexes Sir:…”