[Br:1]Br.[C:3]([C:6]1[CH:7]=[C:8]([C:11]([O:13][CH3:14])=[O:12])[S:9][CH:10]=1)(=[O:5])[CH3:4].Br>C(Cl)(Cl)Cl>[Br:1][CH2:4][C:3]([C:6]1[CH:7]=[C:8]([C:11]([O:13][CH3:14])=[O:12])[S:9][CH:10]=1)=[O:5]Following the procedure of Japan Kokai Tokkyo Koho JP 60 11,487 CA 103:22580m (1985), a solution of bromine (4.29 g, 26.87 mmoles) in 40 ml of chloroform was added dropwise to a stirred solution of methyl 4-acetyl-2-thiophenecarboxylate, prepared according to Example 15 (4.95 g, 26.87 mmoles) in 150 ml of chloroform containing four drops of 50% (v/v) 48% hydrobromic acid/glacial acetic acid. After 10 minutes at 40° C. the solution was cooled to room temperature, concentrated in vacuo and the residue triturated with methanol (25 ml). Filtration furnished an off-white solid (4.96 g, 63%), m.p. 112°-4° C. EIMS (m/z): 264/262 (M+, 11%), 233/231 (M+ -CH3O, 11%), 171/169 (M+ -CH2Br, base); 1HNMR (CDCl3) delta, 8.31 (1H, d, J=1.5Hz), 8.17 (1H, d, J=1.5Hz), 4.29 (2H, s), 3.90 (3H, s).
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