Substituent effects on absorption and fluorescence spectra of carbostyrils
作者:Walter M.F. Fabian、Karlheinz S. Niederreiter、Georg Uray、Wolfgang Stadlbauer
DOI:10.1016/s0022-2860(98)00616-4
日期:1999.3
Abstract Absorption and fluorescence spectra as well as quantum yields of a series of differently substituted carbostyrils (quinolin-2(1H)-ones) are reported. Especially for compounds containing donor substituents in position 6, substantial bathochromic shifts (comparable to analogous coumarins) of both absorption as well as fluorescence transitions are obtained. High absorption intensities and quantum
3-Substituted 4-hydroxy-2(1 H)-quinolones 3, 5, 7 are halogenated with bromine or sulfuryl chloride to yield the quinolinediones 9 or 10. Reaction of 3, 5, 7 with chloroform gives the dichloromethyl quinolinediones 11. Halogen exchange leads from the chloro quinolinediones 10 to fluoro quinolinedones 12 and to azido quinolinediones 13. Similarly the dichloro quinolinedione 10 an reacts to the difluoro quinolinedione 14, which is reduced to the 3-fluoro-4-hydroxyquinolone 16 and reacts again with sulfuryl chloride to give the mixed 3-chloro-3-fluoroquinolinedione 15.
Oxidative Hydroxylierung von heterocyclischen ?-Dicarbonylberbindungen
作者:Wolfgang Stadlbauer、Thomas Kappe
DOI:10.1007/bf00809193
日期:——
Selective formation of glycosidic linkages of N-unsubstituted 4-hydroxyquinolin-2-(1H)-ones
作者:Roman Kimmel、Stanislav Kafka、Janez Košmrlj
DOI:10.1016/j.carres.2010.01.023
日期:2010.4
A comparative study for selective glucosylation of N-unsubstituted 4-hydroxyquinolin-2(1H)-ones into 4-(tetra-O-acetyl-beta-D-glucopyranosyloxy)quinolin-2(1H)-ones is reported. Four glycosyl donors including tetra-O-acetyl-alpha-D-glucopyranosyl bromide, beta-D-glucose pentaacetate, glucose tetraacetate and tetra-O-acetyl-alpha-D-glucopyranosyl trichloroacetimidate were tested, along with different promoters and reaction conditions. The best results were obtained with tetra-O-acetyl-alpha-D-glucopyranosyl bromide with Cs(2)CO(3) in CH(3)CN. In some cases the 4-O-glucosylation of the quinolinone ring was accompanied by 2-O-glucosylation yielding the corresponding 2,4-bis(tetra-O-acetyl-beta-D-glucopyranosyloxy)quinoline. Next, 4-(tetra-O-acetyl-beta-D-glucopyranosyloxy)quinolin-2(1H)-ones were deacetylated into 4-(beta-D-glucopyranosyloxy)quinolin-2(1H)-ones with Et(3)N in MeOH. In some instances the deacetylation was accompanied by the sugar-aglycone bond cleavage. Structure elucidation, complete assignment of proton and carbon resonances as well as assignment of anomeric configuration for all the products under investigation were performed by 1D and 2D NMR spectroscopy. (C) 2010 Elsevier Ltd. All rights reserved.
STADLBAUER, W.;KAPPE, TH., MONATSH. CHEM., 1985, 116, N 8-9, 1005-1015