Sodium hydride → HCID 9965565, compound

Participants

Reaction Steps

3-Chloro-4-fluoroaniline (2.91 g) and 3.16 g of ethyl-2-methylpropionyl acetate were refluxed in toluene (60 ml) in the presence of 0.3 ml of boron trifluoride etherate for 3 hr. The reaction mixture was then washed with a saturated sodium hydrogencarbonate solution and saturated brine and was dried over anhydrous sodium sulfate, and the solvent was then removed by evaporation. The resultant intermediate was refluxed in diphenyl ether for 30 min. The reaction solution was allowed to stand for cooling, and the precipitate was then collected by filtration under the reduced pressure to give 820 mg of a mixture of 2-ethyl-3-methyl-4-hydroxy-6-fluoro-7-chloroquinoline with 2-ethyl-3-methyl-4-hydroxy-5-chloro-6-fluoroquinoline. In 10 ml of tetrahydrofuran was suspended 90.3 mg of 60% sodium hydride. The mixture of 2-ethyl-3-methyl-4-hydroxy-6-fluoro-7-chloroquinoline with 2-ethyl-3-methyl-4-hydroxy-5-chloro-6-fluoroquinoline (starting material 1) (400 mg) was suspended in 10 ml of tetrahydrofuran, and this suspension was added dropwise to the above suspension under ice cooling. The mixture was stirred for one hr. Acetyl chloride (starting material 2) (180 μl) was then added thereto, and the mixture was stirred at room temperature for 3 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. 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 17.5 mg of 2-ethyl-3-methyl-4-acetyloxy-6-fluoro-7-chloroquinoline (compound 18) and 44.6 mg of 2-ethyl-3-methyl-4-acetyloxy-5-chloro-6-fluoroquinoline (compound 19). 1H-NMR data are shown in Table 3.

Provenance & Evidence