m-Chloroperbenzoic acid → 3-Chloromethylsulfonyl-7-fluoro-1-methyl-4-quinolone

Participants

Reaction Steps

6.33 g (0.0232 mole) of monochloroflosequinan (4) and 225 ml of methylene dichloride were placed in a 500 ml round bottom flask and stirred. Into this mixture a 5.98 g of 77% pure m-chloroperoxybenzoic acid (8) was added in four equal portions in 15 minute intervals and the mixture was stirred for an additional 30 minutes to complete oxidation. The reaction mixture was then concentrated to a final volume of 100 ml and the crystals which formed were filtered off and washed with two 10 ml portions of methylene dichloride. After high vacuum drying 5.2 g (77.6% yield) of white crystalline 3-chloromethylsulfonyl-7-fluoro-1-methyl-4-quinolone (9) were collected. The product was 99+% pure (by 1H NMR). 1H NMR, CDCl3, δ=8.52 dd, 1H, J=6.3 & 9.0 Hz, H at C5; 8.41 s, 1H, H at C2; 7.20 dd, 1H, J=2.1 & 9.6 Hz, H at C8; 7.32-7.26 m, 1H, H at C6; 5.03 s, 2H, CH2; 3.94 s, 3H, N—CH3.

Provenance & Evidence