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

Beteiligte Stoffe

Reaktionsschritte

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 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-chlorophenylboronic 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, according to the method of Example 5 to provide the title compound (yield: 130 mg, 70%). mp 154-155° C. 1H NMR (300 MHz, CDCl3) δ 2.74 (s, 3H), 4.88 (q, J=9 Hz, 2H), 7.14 (d, J=9 Hz, 2H), 7.26 (d, J=9 Hz, 2H), 7.31 (d, J=9 Hz, 2H), 7.61 (d, J=9 Hz, 2H), 7.82 (s, 1H). MS (DCI/NH3) m/z 427 (M+H)+. Anal. calc. for C19H14ClF3N2O2S: C, 53.46; H, 3.3; N, 6.56. Found: C, 53.58; H, 3.34; N, 6.42.

Herkunft & Nachweise