[H-].[Na+].C(O[CH:6]([O:10][CH2:11][CH3:12])[C:7]([NH2:9])=[O:8])C.[Br:13][C:14]1[C:18]([CH2:19]Br)=[CH:17][S:16][CH:15]=1.[I-].[Na+].C1[CH2:27][O:26][CH2:25]C1>>[Br:13][C:14]1[C:18]([CH2:19][NH:9][C:7](=[O:8])[CH:6]([O:10][CH2:11][CH3:12])[CH2:25][O:26][CH3:27])=[CH:17][S:16][CH:15]=1To a suspension of sodium hydride (162 mg, 6.74 mmol) in THF (14 mL, 170 mmol) was added 2,2-diethoxyacetamide (949 mg, 6.45 mmol) in portions, followed by 3-bromo-4-(bromomethyl)thiophene (1.50 g, 5.86 mmol) dropwise as a solution in THF (3 mL) and sodium iodide (87.8 mg, 0.586 mmol). The reaction mixture was heated to reflux for 18 h and then concentrated. The residue was then partitioned between water (40 mL) and ethyl acetate (40 mL). The layers were separated and the aqueous layer was further extracted with ethyl acetate (2×30 mL). The combined organic fractions were dried over sodium sulfate, filtered, and concentrated. Purification by ISCO chromatography (5 to 30% ethyl acetate:heptane) afforded 729 mg (35%) of the title compound as a clear, colorless oil. 1H NMR (400 MHz, CDCl3): δ 7.26-7.29 (m, 1 H), 7.23-7.25 (m, 1 H), 6.99 (br. s., 1 H), 4.83 (s, 1 H), 4.44 (dd, J=6.1, 0.8 Hz, 2 H), 3.21-3.98 (m, 4 H), 1.25 (t, J=6.9 Hz, 6 H); MS (ESI): 322.17, 324.15 [M+H]+; HPLC tR=3.26 min (ZQ3, polar—4 min).
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