[Cl:1]N1C(=O)CCC1=O.[CH3:9][C:10]1[NH:14][C:13]([C:15]([O:17][CH2:18][CH3:19])=[O:16])=[CH:12][CH:11]=1.[OH-].[Na+]>C(Cl)(Cl)Cl>[Cl:1][C:11]1[CH:12]=[C:13]([C:15]([O:17][CH2:18][CH3:19])=[O:16])[NH:14][C:10]=1[CH3:9]N-Chlorosuccinimide (0.67 g, 5.08 mmol) was added to a solution of ethyl 5-methyl-1H-pyrrole-2-carboxylate (Intermediate 29, 0.65 g, 4.23 mmol) in chloroform (20 ml). The reaction was warmed to 40° C. and stirred for 4 h, then poured to a beaker containing 2 N NaOH (20 ml) at 0° C. The layers were separated and the aqueous layer was extracted with chloroform 3 times. The combined organic extracts were dried over magnesium sulfate and concentrated. The resultant off-white solid was purified by flash chromatography (hexanes/EtOAc, 16:1) to give the title product as a white solid (0.3 g, 38%). MS (ES): 188 (M+1) for C8H10ClNO2; NMR (CDCl3): 1.34 (t, 3H), 2.27 (s, 3H), 4.30 (q, 2H), 6.76 (s, 1H), 9.07 (brs, 1H).
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