Sodium Hydroxide → 6-(tert-Butoxycarbonyl)-6-azaspiro[2.5]octane-1-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To the solution of 165c (500 mg, 1.76 mmol) in ethanol (8 mL) was added sodium hydroxide (212 mg, 5.3 mmol) in water (4 mL). See FIG. 6. The mixture was stirred at 15° C. for 12 h. The solvent was evaporated under reduced pressure. The aqueous solution was acidified with dilute hydrochloride acid (0.5 M) slowly under ice bath until pH˜4, and extracted with EtOAc (10 mL×3). The combined organic extracts were dried over anhydrous sodium sulfate, filtered, and concentrated to give 6-(tert-butoxycarbonyl)-6-azaspiro[2.5]octane-1-carboxylic acid 165d (390 mg, 83%) as a white solid. 1H NMR (400 MHz, CDCl3): δ 3.52-3.42 (m, 3H), 3.38-3.35 (m, 1H), 1.75-1.72 (m, 2H), 1.58-1.56 (m, 1H), 1.46-1.43 (m, 11H), 1.23-1.21 (m, 1H), 1.02-1.01 (m, 1H).

Provenance & Evidence