4- Hydroxy-quinoline carboxylates

A mixture of 26 parts of 3-carbethoxy-6,7-methylenedioxy-4-hydroxy-quinoline, 16 parts of sodium hydroxide and 50 parts of dimethylformamide is heated at 70° to 75°C for 2 hours, then 31 parts of ethyl iodide is added over 1 hour with continued heating and stirring. After an additional 3 to 4 hours of heating (at 70° to 75°C) and stirring, the mixture is diluted with 500 parts of water, refluxed for 3 to 4 hours, acidified with concentrated hydrochloric acid and filtered to yield 18 to 22 parts of 1-ethyl-1,4-dihydro-6,7-methylene-dioxy-4-oxo-3-quinoline-carboxylic acid, MP 309° to 314°C (decomposes). The analytical sample from dimethylformamide melts at 314° to 316°C (decomposes). 

Interestingly, when carboxylate derivatives are considered, the SET process is irreversible (due to release of CO ) and the degradation rate is maximum when this mechanism is supposed to be operating. On the contrary, when a radical cation or a semiquinone intermediate is invoked, as in the case of quinoline or hydroxy-methoxy-chloro benzenes [60,64], the rate is minimum due to the back reaction. 

Ifenprodil (= l-Methyl-2-hydroxy-2-(4-hydroxyphenyl) ethyl-1 -(4-benzyl-piperidine)] -(aryl piperidine) [at(/o-3-(Indol-2-yl)-8-methyl-8-azabicyclo-[3.2.1] octane] (indolotropane) [Kynurenic acid (= 4-Hydroxy-2-quinolinecarboxylic acid)] (quinoline carboxylic acid) [Memantine (= 1-Amino-3,5 dimethyladamantane)] (amino adamantane, amino cyclic aliphatic) [Methadone (= 6-Dimethylamino-4,4-diphenyl-3-heptanone)] (aryl tertiary amine) [em/o-3-(l -Methylindol-2-yl)-8-methyl-8-azabicyclo-[3.2.1] octane(indolotropane) exo- 3-( 1 -Methylindol-2-yl)-8-methyl-8-... 

Figure 3. Biotransformation cascade of oxolinic acid in fish. A, oxolinic acid B., Glucuronide of oxolinic acid C., 7-hydroxy-6-methoxy derivative (1-ethyl-1,4 dihydro-7-hydroxy-6-methoxy-4-oxo-3-quinoline carboxylic acid) D., 6-hydroxy-7-methoxy derivative (1 -ethyl-1,4-dihydro-6-hydroxy-7-methoxy-4-oxo-3-quinoline-carboxylic acid. E,F. Stars represent unconfirmed sites of glucuronidation of 7-hydroxy-6-methoxy and 6-hydroxy-7-methoxy oxolinic acid derivatives.

Quinoline, 2-cyano-8-hydroxy-hydro lysis metal catalysis, 452 Quinoline, 8-hydroxy-carboxylic acid esters hydrolysis, metal-catalyzed, 438 metal complexes... 

Hydroxy-quinoline carboxylates, prepared using the Could-Jacobs reaction, have also been frequently used as precursors for the synthesis of biologically interesting quinoline compounds. For example, the syndiesis of... 

Quinolobactin, 8-hydroxy-4-methoxy-2-quinoline carboxylic acid, is an alkaloid produced by Pseudomonas fluorescens ATCC17400. The biosynthesis of quinolobactin involves the tryptophan-kynurenine-xanthurenic acid pathway (Figure 6.13). 

Supplement 1953 3242-3457 Hydroxy-carboxylic acids, 190 In i doxylic acid, 226. Carbonyl-carboxylic acids, 284. i Sulphonic acids, 386 Quinoline sul-phonic acid, 390. Amines, 419 2-Aminopyridine, 428. Amino-carboxylic acids, 541 Tryp- tophane, 545. Hydrazines, 563. Azo. compounds, 572. Diazo compounds, 590. ... 

Quinoline-4-carboxylic acid, 3-hydroxy-Pfitzinger synthesis, 2, 446 Quinoline-4-carboxylic acid, 2-methyl-synthesis, 2, 475... 

Quinoline, 8-mercapto-2-methyl-metal complexes, 2, 800 Quinoline, 2-methyl-8-(methylthio)-metal complexes, 2,801 Quinoline, 8-methylthio-metal complexes, 2, 801 Quinoline-2-carboxylic-acid, 8-hydroxy-methyl ester... 

A bacterial strain BN6 oxidizes 5-aminonaphthalene-2-sulfonate by established pathways to 6-amino-2-hydroxybenzalpyruvate that undergoes spontaneous cyclization to 5-hydroxy-quinoline-2-carboxylate (Figure 2.2a) (Nortemann et al. 1993). 

Nuvole et al. stated that the cyclization of 974 and its desmethyl derivative gave tautomeric 9-hydroxy-1,2,3-triazolo[4,5-/]quinoline-8-carboxyl-ates (e.g., 975) or 9-oxo-6,9-dihydro-l,2,3-triazolo[4,5-/]quinoline-8-car-boxylates (e.g., 976, depending on the cyclization conditions (in xylene on the action of polyphosphoric acid (PPA) vs. in DMF on the action of PPA and in Dowtherm A under boiling vs. in polyphosphate (89FES609, 89FES619). 

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