Wolfgang Stadlbauer

Substituent effects on absorption and fluorescence spectra of carbostyrils

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 yields are found for 7-donor substituted isomers. Semiempirical molecular orbital calculations (AM1 for structures, ZINDO for electronic transition energies) prove to be a suitable tool for the prediction of absorption and fluorescence properties of these compounds. Ab initio and density functional calculations establish the lactam form as the dominant tautomer of the parent quinolin-2(1H)-one.

Halogenation reactions in position 3 of quinoline-2,4-dione systems by electrophilic substitution and halogen exchange

Summary3-Substituted 4-hydroxy-2(1H)-quinolones3,5,7 are halogenated with bromine or sulfuryl chloride to yield the quinolinediones9 or10. Reaction of3,5,7 with chloroform gives the dichloromethyl quinolinediones11. Halogen exchange leads from the chloro quinolinediones10 to fluoro quinolinedones12 and to azido quinolinediones13. Similarly the dichloro quinolinedione10 an reacts to the difluoro quinolinedione14, which is reduced to the 3-fluoro-4-hydroxyquinolone16 and reacts again with sulfuryl chloride to give the mixed 3-chloro-3-fluoroquinolinedione15.Zusammenfassung3-Substituierte 4-Hydroxy-2-chinolone3,5,7 reagieren mit elementarem Brom oder Sulfurylchlorid zu den 3-Halogen-chinolindionen9 oder10. Mit Chloroform reagieren die Hydroxychinolone3,5,7 zu den 3-Dichlormethylchinolondionen11. Halogenaustausch an10 führt zu den 3-Fluorchinolindionen12 und zu 3-Azidochinolindionen13. Ähnlich reagiert 3,3-Dichlorochinolindion10 an zu 3,3-Fluorchinolindion14, das zum 3-Fluor-4-hydroxychinolon16 reduziert werden kann und in weiterer Folge mit Sulfurylchlorid zum gemischten 3-Chlor-3-fluor-chinolindion15 reagiert.

Methoden zur Darstellung von 4-Azido-2(1H)-chinolonen

Abstract4-Hydroxy-2-quinolones1 are generally found to be converted to the 4-azidocompounds3via the 4-chloroquinolones2, the 4-tosyloxyquinolones6, or the 4-aminoquinolones4, respectively. Choice of the reaction conditions and yields depend on the substituent in position 3 of the quinoline nucleus. For comparison the O-analogous coumarin derivatives9 have been studied to give the 4-azidoderivatives11via the 4-chlorocoumarins10.

Malonates in Cyclocondensation Reactions

The use of malonates such as diethyl malonates 9, (chlorocarbonyl)ketenes 15 and bis(2,4,6-trichlorophenyl) malonates 18 as reagents for cyclocondensation with 1,3-dinucleophiles to give six-membered heterocycles is described. Further attempts to use malonates such as bis(trimethylsilyl) malonates 19 and bis(carbamimidoyl) malonates 29 as new cyclocondensation agents are described .

Synthese von Benzofuranen durch Cyclodehydrierung von Phenylmalonylheterocyclen

Phenylmalonyl heterocyclic compounds such as the quinolones1a–c or3, benzoquinolizinones6a, b and the phenalenones8a, b can be converted to benzofuranes (2a–c, 7a, b and9a, b) by cyclodehydrogenation with Pd/C in boiling diphenyl ether. 2-Phenylchinchonic acid (10) reacts under the same conditions to the dimeric benzofuroquinoline12: the decarboxylated quinoline11 however gives the monomer13.

Eine einfache Synthese von 11H-Indolo[3,2-c]chinolin-6-onen

Abstract11H-Indolo[3,2-c]quinolin-6-ones, which are containing the γ-carboline ring system, can be easily synthesized from 4-azido-3-phenyl-2(1H)-quinolones, which are obtained in a two step reaction from 4-hydroxy-3-phenyl-2(1H)-quinolones. Cyclization of the azides can be realized by irradiation or thermal reaction.

Isatoic Anhydrides and Their Uses in Heterocyclic Synthesis

Publisher Summary This chapter focuses the use of Isatoic Anhydrides (IA) as a starting material for heterocyclic compounds. Other fields of application are not included: for example, reactions leading to open-chain anthranilic acid derivatives, use in the manufacture of agricultural chemicals, dyes, pigments, cross-linking agents and chain stoppers in resins and other uses in polymer and rubber chemistry, use as a modifier in protein and carbohydrate substrates (wool, paper, textiles), use as a petroleum additive (fuel and lubricants), use as a blowing agent for polymer foams, a flameproofing agent, and a corrosion inhibitor, use in metal finishing, for foods and beverages, soaps and detergents, perfumes, cosmetics, and use in pharmaceuticals and medicines. The chapter discusses the synthesis of IA and related compounds that includes three types of reactions. IA enters into condensation and substitution reactions with ease. The hetero ring is highly susceptible to cleavage and can be N-substituted with or without ring opening. The chapter discusses the formation of anthranilic acid amides and hydrazides and reactions to heterocycles.

REACTIONS OF 3-ACYL-4-HYDROXY-2(1H)-QUINOLONES WITH NITROGEN BASES

3-Acyl-4-hydroxy-2-quinolones 1 react with amines to yield 3-aminomethylene quinolinediones 2. With hydroxylamine the corresponding oximes 3 are obtained, which cyclize on heating via a thermal Beckmann rearrangement to oxazolo[5,4-c]quinolones 4. The oxazoles can be ringopened in the presence of acids to give 3-acylamino-4-hydroxyquinolones 5. The hydrazones 6, obtained from 3-acyl-4-hydroxy-2-quinolones 1 and hydrazines, cyclize either to pyrazolo[4,3-c]quinolones 7 or give mixtures of 7 and the dimeric azino-diethylidenequinolones 8. INTRODUCTION 4-Hydroxy-2-quinolines, their oxygen derivatives and the monocyclic debenzo derivatives having aliphatic acyl groups in position 3 have found great interest in the last years because of their biological properties (4). Reaction of the keto group of this class of compounds with nitrogen bases such as amines, hydroxylamines and hydrazines offers an entry to nitrogen containing carbonyl derivatives. Some of them have caused great interest because of their biological (5) or technical properties (6). RESULTS AND DISCUSSION We have shown recently, that 3-acyl-4-hydroxyquinolones of type 1 could be aminated in an equilibrium process at the keto moiety of the 3-acyl substituent by reaction with aqueous ammonia or amines with acetic acid as catalyst (7). The isomeric 4-amino-3-acylquinolones could be excluded by synthesis of the corresponding compounds via an independent pathway. Aliphatic and aromatic amines could be shown to react with 1a-f in ethanol as solvent also by using dimethylaminopyridine as basic catalyst to obtain the 4-hydroxy-3-iminoethyl-2-quinolones 2a-l in good yields. H NMR spectroscopic studies have shown that compounds of this type deriving from 3-carbaldehydes (instead of 3-acyl groups in 2) exist mainly in the tautomeric enaminoketone form (8) by using the aldehydic/olefinic proton as probe. The lack of this proton in 2 does not allow a similar assignment, and the carbonyl frequencies of the 4-oxo group in infrared spectra, which are usually a good hint for discussion of tautomers (9), are not helpful because of hydrogen bondings between the 4-hydroxy/4-oxo group with the imino/amino group, resp. Investigations by deuterium isotope effects on C NMR chemical

Oxidative Hydroxylierung von heterocyclischen β-Dicarbonylberbindungen

Abstract3-Substituted 4-hydroxy-2-quinolones (1), 5-substituted barbituric acids (3) and 4-substituted pyrazolidine-2,4-diones were oxidized to yield the corresponding hydroxyderivatives2,4 or9, respectively.

Synthesis of new 2-, 3-, and 4-substituted azidoquinolines: inhibitors of human blood platelet aggregation in vitro

Abstract A series of 2-, 3- and 4-substituted azidoquinoline derivatives were synthesized and tested for their ability to inhibit human platelet aggregation in vitro triggered by adenosine diphosphate (15 μM), collagen (5 μg/ml), platelet activating factor (10 μM), or the stable prostaglandin H2 mimetic, U46619 (4 μM). The most active compounds (IC50 2.5–68.3 μM) were the germinal 3,3-diazides (4f and 4g) and the 4-azido-3-nitroquinolines (6f and 6g).