Water → HCID 22222477, compound

Participants

Reaction Steps

In ml of tetrahydrofuran was suspended 96 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) (480 mg) prepared as described in Example 6 was suspended in 10 ml of tetrahydrofuran, and this suspension was added dropwise to the above suspension under ice cooling. After stirring for one hr, 300 mg of isopropyl chloroformate (starting material 2) was added thereto, and 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. The solvent was then removed by evaporation under the reduced pressure. The crude product thus obtained was purified on Wako Gel C-200 (200 ml; elution solvent=n-hexane-ethyl acetate (10:1)) to give 345.1 mg of 2-ethyl-3-methyl-4-isopropoxycarbonyloxy-6-fluoro-7-chloroquinoline (compound 22) and 170.7 mg of 2-ethyl-3-methyl-4-isopropoxycarbonyloxy-5-chloro-6-fluoro -quinoline (compound 23). 1H-NMR data are shown in Table 3.

Provenance & Evidence