Sodium hydride → HCID 71477845, compound

Participants

Reaction Steps

4,5,6,7-tetrabromo-1H-benzimidazole (115 mg, 0.26 mmol) and NaH suspension (12 mg, ˜0.28 mmol) were stirred in DMF for 30 min and then 8-bromooctanoic acid methyl ester (182 mg, 0.77 mmol) was added. The solution was stirred for 2 days and then evaporated to dryness. The residue was purified by flash chromatography (CHCl3: methanol; 20:1 by volume). The methyl ester was hydrolyzed in the mixture of methanol and aqueous KOH for 1 hour and the solvents were removed in vacuum. The obtained residue was partitioned between ethyl acetate and KHSO4, the organic layer was dried and evaporated to yield 8-(4,5,6,7-tetrabromo-1H-benzimidazole-1-yl)octanoic acid (95 mg, 62% over two steps). 1H NMR (200 MHz; DMSO6d; Me4Si) 1.28 (m, 6H), 1.48 (m, 2H), 1.76 (m, 2H), 2.19 (t, J=7.3 Hz, 2H), 4.48 (t, J=7.6 Hz, 2H), 8.51 (s, 1H), 11.91 (br, 1H). 13C NMR (50 MHz; DMSO6d; Me4Si) 24.3, 25.5, 28.1, 28.3, 31.5, 33.6, 46.4, 106.5, 116.6, 120.4, 122.3, 131.3, 143.7, 148.9, 174.4. B. Synthesis of TBBI-OcA-(D-Asp)-(L-Asp)5-(L-Lys)-OH

Provenance & Evidence