Hydrochloric Acid → 6-[5-(2-Oxo-1,3,3a,4,6,6a-hexahydrothieno[3,4-d]imidazol-4-yl)pentanoylamino]hexanoic acid

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Reaction Steps

5-(2-Oxo-hexahydro-thieno[3,4-d]imidazol-4-yl)-pentanoic acid 2,5-dioxo-pyrrolidin-1-yl ester (2; 0.35 g, 1.03 mmol) was completely dissolved in DMF (3 mL) with gentle warming. After cooling the 2 solution to room temperature without reprecipitation, it was mixed with a solution of ε-aminocaproic acid (0.18 g, 1.37 mmol) in sodium bicarbonate buffer (0.1 M, pH 8.0; 4 mL) while stirring. After 4 h at room temperature, the reaction mixture was acidified by HCl solution (1 N) to assist in the formation of white precipitate. The white solid was washed with cold HCl solution, dried over ether, and air-dried to afford 3 (0.30 g; 80.5%). 1H NMR (400 MHz) (DMSO) δ: 7.78 (s, 1H, CONH), 6.46 (s, 1H, CONH), 6.38 (s, 1H, CONH), 4.32 (t, 1H, CHN), 4.14 (t, 1H, CHN), 3.11 (dd, 1H, CHS), 3.02 (t, 2H, CH2NH), 2.84 (d, 1H, CHHS), 2.59 (d, 1H, CHHS), 2.18 (t, 2H, CH2COOH), 2.05 (t, 2H, CH2CO), 1.23-1.68 (m, 12H). 13C NMR (100.67 MHz) (DMSO) δ: 174.45, 171.79, 162.70, 61.03, 59.18, 55.43, 35.21, 33.60, 28.90, 28.02, 25.97, 25.33, 24.22. HRMS (ESI) calculated for C16H27N3O4S, [M+Na]+ 380.1620 (calcd.), 380.1617 (found).

Provenance & Evidence