Showing papers by "Dong Wang published in 2006"
TL;DR: In this paper, a reversal of the standard regiochemistry of the Skraup-Doebner-Von Miller quinoline synthesis was observed when anilines were condensed with gamma-aryl-beta,gamma-unsaturated alpha-ketoesters in refluxing TFA.
Abstract: A reversal of the standard regiochemistry of the Skraup-Doebner-Von Miller quinoline synthesis was observed when anilines were condensed with gamma-aryl-beta,gamma-unsaturated alpha-ketoesters in refluxing TFA. The reaction is proposed to involve 1,2-addition of the anilines to gamma-aryl-beta,gamma-unsaturated alpha-ketoesters to form Schiff's base adducts, followed by cyclization and oxidation. The products were unambiguously shown to the 2-carboxy-4-arylquinolines by spectroscopy and X-ray crystallographic analysis.
123 citations
TL;DR: Tetrahydropyran compounds can be directly synthesized from allylbromide and carbonyl compounds by means of one-pot Babier-Prins cyclization promoted by BPyX/SnX′2 or BBIMBr/SnBr2 under solvent-free conditions as mentioned in this paper.
28 citations
TL;DR: In this paper, three dammarane monodesmosides, named notoginsenosides Ft(1) (1) Ft(2) (2), and Ft(3) (3) together with three known ginsenoside, were obtained from a mild acidic hydrolysis of the saponins from notoggineng (Panax) (BURK.) F. HEN) leaves.
Abstract: Three new dammarane monodesmosides, named notoginsenosides Ft(1) (1) Ft(2) (2), and Ft(3) (3) together with three known ginsenosides, were obtained from a mild acidic hydrolysis of the saponins from notoginseng (Panax notoginseng (BURK.) F. H. CHEN) leaves. Their structures were elucidated to be (3 beta,12 beta,20 beta)-12,20-dihydroxydammar-24-en-3-yl O-beta-D-xylopyranosyl-(1 -> 2)-O-beta-D-glucopyranosyl-(1 -> 2) 2)-O-beta-glucopyranoside (1), (3 beta,12 beta)-12,20,25-trihydroxydammaran-3-yl O-beta-D-Xylopyranosyl(1 -> 2 )-O-beta-D-glucopyranosyl-(1 -> 2)-beta-glucopyranoside (2), and (3 beta,12 beta,24 xi)-12,20,24-trihydroxydammar-25-en-3-yl O-beta-D-xylopyranosyl-(1 -> 2)-O-beta-D-glucopyranosyl-(1 -> 2)-beta-D-glueopyranoside (3), by means of spectroscopic evidences. The known ginsenosides Rh-2 and Rg(3) 4-6 were obtained as the major products from this acidic deglycosylation.
25 citations
TL;DR: In this paper, an exciplex can be formed due to the charge transfer between the lowest unoccupied molecular orbital of the acceptor and the highest occupied molecular orbital (HOMO) of the donor.
Abstract: An exciplex can be formed due to the charge transfer between the lowest unoccupied molecular orbital (LUMO) of the acceptor and the highest occupied molecular orbital (HOMO) of the donor. By introducing a mixing layer composed of [N,N′-diphenyl-N,N′bis (3-methylphenyl)-1,1′-diphenyl-4,4′-diamine] (TPD) and europium(dibenzoylmethanato)3(bathophenanthroline) [Eu(DBM)3bath] and a graded interface, elimination of light emission from the exciplex and significant luminescence enhancement of trivalent europium ions (Eu3+) in organic light emitting devices have been achieved. The elimination mechanism of exciplex emission based on the concept that an exciplex can be formed between LUMO of the acceptor (Eu complex) and HOMO of donor (TPD) was investigated. To comprehensively understand the mechanism, devices consisting of a Eu(DBM)3bath as the emitting material and the devices using other rare-earth (RE) complex [RE(DBM)3bath] as the emitting material were fabricated with the same device configuration. As a refere...
15 citations