Quinolinones, 4-hydroxy

Hydroxy-1-methyl-2-quinolinone 4-Hydroxy-A/-metbyicarbostyrii CioHgNOj 1677-46-9 176.184 266 si DMSO... 

Hydroxy-1-methyl-2- quinolinone 4-Hydroxy-/ /-methylcarbostyril C10H9NO2 1677-46-9 175.184 265 si DMSO... 

Since polar solvents would be expected to stabilize polar forms, a retreat towards the hydroxy tautomer (71) would be predicted in solvents less polar than water, and in the vapour phase. This is borne out in practice at equilibrium both 2- and 4-hydroxypyridine (as well as the 3-hydroxy compound, which even in water exists as an approximate 1 1 mixture of OH and NH forms) exist as such, rather than as the pyridinones. However, the 2- and 4-quinolinones remain in the NH (keto) forms, even in the vapour phase. Hydrocarbon or other solvents of very low polarity would be expected to give results similar to those in the vapour phase, but intermolecular association by hydrogen bonding often leads to a considerably greater proportion of polar tautomers being present than would otherwise have been predicted (77ACR186, 78JOC177). 

CN (R, S )-8-hydroxy-5-[]-hydroxy-2-[(l-methylethyl)amino]butyl]-2(l//)-quinolinone... 

Methylquinoline (2) 3-methyl-2(lH)quinolinone (3) 5,6-dihydro-5,6-dihydroxy-3-me thy 1-2(1 H)quinolinone (4) 6-hydroxy-3 -methyl-2( 1 H)quinolinone (5) 5,6-dihydroxy-3-methyl-2(lH)quinolinone (6) 3-methyl-2,4,6-trihydroxypyridine (1) 4-Methylquinoline (2) 4-methyl-2(lH)quinolinone (3) 7,8-dihydro-7,8-dihydroxy-4-methy 1-2(1 H) quinolinone (4) 8-hydroxy-4-methyl-2(lH)quinolinone (5) 7,8-dihydroxy-4-methyl-2(1 H)quinolinone (6) 6-hydroxy-5-(2-carboxyethenyl)-4-methyl-2( 1 H)pyridone... 

Quinaldine (2-methyl-quinoline) (2) 2-methyl-4(lH)-quinolinone (3) 3 -hydroxy-2-methyl-4( 1 H)quinolinone (4) N-acetylanthranilic acid (5) Anthranilic acid (6) Catechol (1) Quinoline (2) 2(lH)quinolinone (3) 8-hydroxy-2(lH)quinolinone (4) 8-hydroxycoumarin (5) 2, 3-dihydroxyphenylpropionic acid... 

Chiral butyrolactones of type 27 and 28 have substantial value in asymmetric synthesis because they contain readily differentiable difunctional group relationships e.g. 1,5-di-carboxylic acid, 1,4-hydroxy carboxylic acid, 1,6-hydroxy-carboxylic acid, 1,6-diol etc.) that would be difficult to assemble by existing asymmetric condensation and pericyclic processes. Applications of these chiral derivatives of glutaric acid to syntheses of indole, indoline and quinolinone alkaloids are illustrated in Schemes 16-18. 

Thus, while the 3-hydroxyisoquinoline-3-isoquinolinone equilibrium (80 81) and that of the cinnoline derivatives (82 83) favour the keto forms (81, 83), the proportion of hydroxy tautomers is considerably greater than in the corresponding unfused systems. The benzo-fusion in 2- and 4-quinolinone and in 1-isoquinolinone has the effect of reducing the aromaticity of the heterocyclic ring, and consequently of lowering the proportion of the hydroxy tautomers. 

N1 - 2(1H)-QUINOLINONE 6-HYDROXY-5-(l-HYDR0XY-2-((l-HETHYLETHYL)AHINO)BUTYL)-> NONOHYDROCHLORIDE, HEHIHYDRATE (R, S )-t4-)-... 

In the 8-hydroxy-2(l//)quinolinone (277) the bridge between the oxygen and the nitrogen is formed from methylene bromide giving the angular fused oxazoline ring (73JA5003). 

Pyrazolo[3,4-Z)]pyridines, the 7-chloro-6-fluoro-2,4-dimethylquinoline and its mercapto-thiadiazolyl or oxadiazolyl quinolines 21 were prepared via Diels-Alder reaction conversion of methyl 2-(3-oxo-3-phenylpropenylamino)benzoate into 3-benzoyl-l.S -quinolin-4-one 22 . A mixture of aniline derivatives and malonic ester gave a variety of 3-aryl-4-hydroxyquinolin-2(l//)-ones 23. Condensation of isatins with ketones afforded quinoline-4-carboxylic acids. 2-Aryl-l,2,3,4-tetrahydro-4-quinolinones 22 and carbazolylquinolone were also prepared. The substitution of 2-chloroquinoline gave the 2-substituted quinolines. Basic alumina has catalyzed the C-C bond formation between 2-hydroxy-1,4-naphthoquinone and 2-chloroquinoline derivative to give 21. Reaction of organic halides with 8-hydroxyquinolines gave the respective ethers. The azodye derivatives of 21 were prepared in the absence of solvent. Silica gel catalyzed the formation of 2-ketomethylquinolines from reaction of 2-methylquinolines with acyl chlorides. 

Wang resin-esterified cyanoacetic acid 79 is an appropriate precursor for the synthesis of these scaffolds. C-Acylation with a number ofisatoic anhydrides provided a set of intermediates 80, which cychzed on heating in toluene to give hydroxy-quinolinones 81 in yields of 22-65% and purities of 72-97% (Scheme 22) [37]. 

N.27) 2(177)-quinolinone, 4-methyl-, 4-methyl-2-quinolone, 4-methyl-1 (H) -qulnolin-2-one [607-66-9] tautomeric form 2-quinolinol, 4-methyl-, 4-methylquinolin-2-ol, 2-hydroxy-4-methylquinoline [84909-43-3]... 

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