Cesium carbonate → tert-Butyl {2-[3-(tert-butoxycarbonyl-phenethyl-amino)-propylsulfanyl]-benzoimidazol-1-yl}-acetate

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Reaction Steps

2-[3-(tert-Butoxycarbonyl-phenethyl-amino)-propylsulfanyl]-benzoimidazole (Precursor J-01c, 239 mg, 0.58 mmol), tert-butyl bromoacetate (136 mg, 103 μl, 0.70 mmol) and cesium carbonate (227 mg, 0.70 mmol) are dissolved in dry DMF (6 ml) and allowed to stir for 1 h at rt. N-(2-Mercaptoethyl)aminomethyl polystyrene (1.4 mmol/g, 0.5 g, 0.36 mmol) is added and the crude mixture is stirred at rt for 1 h. After filtration and removal of the solvent in vacuo, the crude product is diluted in dichloromethane, washed with a 10% aqueous citric acid solution and with a saturated aqueous NaHCO3 solution. The organic phase is dried over MgSO4 and the solvent evaporated in vacuo, yielding the title compound: tR=2.79 min (LC-2), ESI-MS (neg.): m/z 526.61 [M−H]+; 1H-NMR (CDCl3): δ (ppm) 1.46 (s, 18H, 2×tBu), 2.00 (m, 2H, SCH2CH2), 2.85 (m, 2H, CH2Ph), 3.26-3.85 (m, 6H), 4.77 (s, 2H, CH2CO2), 7.44-7.59 (m, 8Harom), 7.94 (m, 1Harom).

Provenance & Evidence