2-Benzyl-4-chloro-5-methoxypyridazin-3(2h)-one → 2-benzyl-4-chloro-5-[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-(trifluoromethyl)sulfonyloxy-analog according to the method of Example 8. Subsequent coupling to 4-(methylthio)phenylboronic acid, according to the method of Example 9, provided 2-benzyl-4-chloro-5-[4-(methylthio)phenyl]-3(2H)-pyridazinone. This intermediate was coupled with 4-chloro-3-fluorophenylboronic acid according to the method of Example 6. This product was N-debenzylated according to the method of Example 11 and N-alkylated with 2-iodo-1,1,1-trifluoroethane according to the method of Example 20. The resulting sulfide was oxidized to the corresponding sulfoxide 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 214-215° C. 1H NMR (300 MHz, CDCl3) δ 4.82 (s, 2H), 4.88 (q, J=9 Hz, 2H), 6.88 (m, 1H), 7.09 (dd, J=9 Hz, 3 Hz, 1H), 7.31 (d, J=9 Hz, 1H), 7.32 (d, J=9 Hz, 2H), 7.90 (s, 1H), 7.92 (d, J=9 Hz, 2H). MS (DCI/NH3) m/z 462 (M+H)+. Anal. calc. for C18H12F4ClN3O3S: C, 46.81; H, 2.61; N, 9.09. Found: C, 46.79; H, 2.59; N, 8.86.

Provenance & Evidence