Ethyl bromoacetate → 1-((S)-2-Benzyloxycarbonylaminopropyl)-1H-furo[2,3-g]indazole-7-carboxylic acid ethyl ester

Beteiligte Stoffe

Reaktionsschritte

To a stirred solution of the product from Step C (0.20 g, 0.56 mmol) in DMF (10 mL) was added potassium carbonate (0.23 g, 1.68 mmol) followed by ethyl 2-bromoacetate (0.07 mL, 0.62 mmol) at room temperature and the resultant solution was heated at 70° C. for 20 h. Saturated aqueous ammonium chloride (20 mL) was added followed by ethyl acetate (50 mL). The organic layer was separated and the aqueous was extracted with ethyl acetate (3×50 mL). The combined organic layers were washed with brine (30 mL), dried and evaporated. The residue was purified by chromatography (silica, 50% ethyl acetate in hexane) to give an oil (0.10 g, 42%): MS(ES) m/z 422 (M+); 1H NMR (CDCl3) δ 8.17 (s, 1H), 8.05 (s, 1H), 7.72 (d, 1H, J=8.8 Hz), 7.43 (d, 1H, J=8.8 Hz), 7.33 (m, 5H), 5.05-5.09 (m, 2H), 4.58 (m, 1H), 4.30 (m, 2H), 1.45 (t, 3H, J=7.2 Hz), 1.17 (d, 3H, J=6.8 Hz).

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