Lithium hydroxide, monohydrate → 5-(tert-butoxycarbonyl)-2-oxa-5-azaspiro[3.4]octane-7-carboxylic acid

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Reaction Steps

A mixture of 5-tert-butyl 7-ethyl 2-oxa-5-azaspiro[3.4]octane-5,7-dicarboxylate (514 mg, 1.80 mmol) and lithium hydroxide monohydrate (378 mg, 9.0 mmol) in 1 mL of H2O and 10 mL of MeOH was stirred at room temperature overnight. The resulting mixture was concentrated in vacuo. The residue was stirred with saturated aqueous solution of 2-hydroxypropane-1,2,3-tricarboxylic acid (15 mL) and then extracted with DCM (15 mL×2). The combined organic layers were dried over Na2SO4 and then concentrated in vacuo to afford 5-(tert-butoxycarbonyl)-2-oxa-5-azaspiro[3.4]octane-7-carboxylic acid (444 mg, yield: 95.9%) as a white solid.

Provenance & Evidence