4-Quinolinols

The reagent of Step 2 was prepared by reacting 2,8-bis(trifluoro-methyl)-bromoquinoline with 4-hydroxymethylbutyl ketone and is described by the author. The preparations of other 4-quinolinol intermediates was also provided by the author and others (2) as illustrated in Eq. 2 ... 

C. 7-Chloro-4-quinolinol and 4,7-dichloroquinoUne. The above air-dried acid (Note 7) is suspended in 1 1. of Dowtherm A in a 2-1. flask equipped with a stirrer and a reflux condenser. The mixture is boiled for 1 hour under a stream of nitrogen to assist in the removal of the water (Note 8). The clear, light-brown solution is cooled to room temperature, and 90 ml. (150 g., 0.98 mole) of phosphorus oxychloride is added. The temperature is raised to 135-140°, and the mixture is stirred for 1 hour. The reaction mixture is cooled and poured into a separatory funnel. The portion of the mixture adhering to the flask is rinsed into... 

If the 7-chloro-4-quinolinol is desired, it is more convenient to effect the decarboxylation without a solvent. ... 

Pyridonecarboxylic and 0-hydroxyquinolinecarboxylic acids can be similarly decarboxylated. 4-Hydroxy-3-quinolinecarboxylic acid, for example, can be converted into 4-quinolinol by either of the two following methods 32... 

The dry powdered acid is heated at its melting point in a metal-bath until evolution of carbon dioxide ceases. The crude 4-quinolinol is dissolved in ethanol and decolorized by charcoal. The product obtained on evaporation of the alcohol is further purified by recrystallization. 

Methyl-2- 2-nonenyt)-4-quinolinol. SF 2420B. Antibiotic SF 2420B... 

Di-Me ether [99878-76-9]. 4-Hydroxy-7,8 dimethoxyquinoline. 7,8-Dimethoxy-4 lll)-quinolinone. 7,8-Dimethoxy-4-quinolinol C H N03 M 205.213 Cryst. (EtOAc/MeOH). Mp 187-190°. 

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