Lithium Hydroxide → 1-((S)-2-Benzyloxycarbonylaminopropyl)-1H-furo[2,3-g]indazole-7-carboxylic acid

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Reaction Steps

To a solution of the product of Step A, Example 2 (0.15 g, 0.31 mmol) in ethanol (10 mL) was added lithium hydroxide (0.026 g, 0.62 mmol) in water (1 mL) and stirred at room temperature for 16 h. The reaction mixture was evaporated to a residue and a saturated aqueous solution of ammonium chloride (20 mL) was added followed by the addition of phosphoric acid (1 M) until the solution was neutral. The mixture was extracted with ethyl acetate (3×50 mL) and the combined extracts were washed with brine (30 mL), dried and evaporated. The residue was purified by chromatography (silica, dichloromethane, 5% methanol in dichloromethane, 10% methanol in dichloromethane) to give an oil (0.12 g, 98%): MS (ES) m/z 394 (M+); 1H NMR (CD3OD) δ 7.91 (s, 1H), 7.81 (s, 1H), 7.58 (d, 1H, J=8.8 Hz), 7.25 (d, 1H, J=8.8 Hz), 7.14-7.02 (m, 5H), 4.81 (s, 2H), 4.49-4.42 (m, 2H), 4.17 (m, 1H), 1.18 (d, 3H, J=6.8 Hz).

Provenance & Evidence