Hydrochloric Acid → HCID 178437487, compound

Temperature

50 °C

2-Ethyl-3-methyl-4-cyclopropanecarbonyloxy-6,7-difluoroquinoline (5.5 g) prepared as described in Example 1 was dissolved in 50 ml of methanol. A solution of 2.5 g of sodium hydroxide in 50 ml of water was added to this solution, and the mixture was stirred at 50° C. for 3 hr. The reaction solution was allowed to stand for cooling and was then poured into 50 ml of water. The mixture was neutralized with 1N hydrochloric acid, and the precipitate was then collected by filtration to give 5.1 g of 2-ethyl-3-methyl-4-hydroxy-6,7-difluoroquinoline. In 20 ml of tetrahydrofuran was suspended 96 mg of 60% sodium hydride. Separately, 446 mg of the 2-ethyl-3-methyl-4-hydroxy-6,7-difluoroquinoline (starting material 1) was suspended in 10 ml of tetrahydrofuran, and this suspension of starting material 1 was added dropwise to the above suspension under ice cooling. The mixture was stirred for 1 hr, and 188.4 mg of acetyl chloride (starting material 2) was then added thereto. The mixture was stirred at room temperature for 15 hr. The reaction solution was poured into water, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with a saturated aqueous sodium hydrogencarbonate solution and saturated brine and was then dried over anhydrous sodium sulfate, and the solvent was then removed by evaporation under the reduced pressure. The crude product thus obtained was purified on Wako Gel C-200 (100 ml; elution solvent=n-hexane-ethyl acetate (10:1)) to give 168.6 mg of 2-ethyl-3-methyl-4-acetyloxy-6,7-difluoroquinoline (compound 3). 1H-NMR data are shown in Table 3.

1. temperaturefor cooling
2. filtrationthe precipitate was then collected by filtration

ORD record

ord-00e91ae11eb940d2875abfb58bd9f32b

Source dataset

uspto-grants-2006_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07022855B2