2-Benzyl-4-chloro-5-methoxypyridazin-3(2h)-one → 2-benzyl-4-chloro-5-[3-fluoro-4-(methylthio)phenyl]3(2H)-pyridazinone

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Reaction Steps

2-Benzyl-4-chloro-5-methoxy-3(2H)-pyridazinone (J. Het. Chem., 1996, 33, 1579-1582) was converted to the 5-hydroxy-analog according to the method of Example 7 and then to the 5-trifluoromethylsulfonyloxy-analog following the method of Example 8. Subsequent coupling to 3-fluoro-4-(methylthio)phenylboronic acid, according to the method of Example 9, provided 2-benzyl-4-chloro-5-[3-fluoro-4-(methylthio)phenyl]-3(2H)-pyridazinone. This intermediate was coupled in the 4-position with 4-fluorophenylboronic acid following the method of Example 6. This product was N-debenzylated according to the method of Example 11 and N-arylated with 4 fluoroiodobenzene according to the method of Example 62. The resulting sulfide was oxidized with one equivalent of meta-chloroperoxybenzoic acid to provide the methylsulfoxide which was converted to the sulfonamide final product according to the method of Example 68 (yield: 500 mg, 75%). mp 222-224° C. 1H NMR (300 MHz, CDCl3) δ 5.06 (s, 2H), 7.01 (t, J=9 Hz, 2H), 7.06 (d, J=9 Hz, 2H), 7.10 (d, J=9 Hz, 2H), 7.18 (t, J=9 Hz, 2H), 7.69 (dd, J=9 Hz, 3 Hz, 2H), 7.88 (t, J=9 Hz, 1H), 7.95 (s, 1H). MS (DCI/NH3) m/z 458 (M+H)+. Anal. calc. for C22H14F3N3O3S: C, 57.76; H, 3.08; N, 9.18. Found: C, 57.5; H, 3.15; N, 8.8.

Provenance & Evidence