[C:1]([O:5][C:6]([NH:8][C:9]1[CH:14]=[CH:13][N:12]=[C:11]([O:15][CH3:16])[CH:10]=1)=[O:7])([CH3:4])([CH3:3])[CH3:2].CN(C)CCN(C)C.[Li]CCCC.[I:30]I.[Cl-].[NH4+]>C(OCC)C.C1COCC1>[C:1]([O:5][C:6]([NH:8][C:9]1[CH:14]=[CH:13][N:12]=[C:11]([O:15][CH3:16])[C:10]=1[I:30])=[O:7])([CH3:4])([CH3:3])[CH3:2]
A solution of 4-[(tert-butoxycarbonyl)amino]-2-methoxypyridine (1.8 g, 8.03 mmol, 1.0 equiv) in 100 mL of anhydrous diethyl ether was treated with 2.79 mL of N,N,N′,N′-tetramethylethylenediamine (18.5 mmol, 2.3 equiv) under an inert atmosphere. The resulting solution was cooled to −78° C., treated with n-BuLi (2.5 M, 7.2 mL, 18.0 mmol, 2.24 equiv) and warmed to −7° C. The reaction was stirred at −7° C. to 0° C. for 3 hours, cooled to −78° C. and treated with a solution of iodine (3.05 g, 12 mmol) in 30 mL of anhydrous THF. The resulting mixture was stirred to room temperature for 16 hours. 200 mL of saturated ammonium chloride solution and 100 mL of diethyl ether were added. The phases were separated and the organic layer was washed with 100 mL of sodium thiosulfate (10% aqueous solution), dried over sodium sulfate, decanted, and concentrated in vacuo. Chromatography on SiO2 (100% dichloromethane to 5% methanol in dichloromethane, gradient) provided the title product (650 mg, 23% yield) as a white wax.
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