Lithium hydroxide, monohydrate → (2S,4S)-1-(tert-butoxycarbonyl)-4-cyanopyrrolidine-2-carboxylic acid

Participants

Reaction Steps

A solution of N-boc-cis-4-cyano-L-proline methyl ester (800 mg, 3.15 mmol) in MeOH (27 mL) was cooled to 0° C. and LiOH.H2O (792 mg, 18.9 mmol) was added. The colorless solution was allowed to reach RT and stirred for 4 h. LiOH.H2O (792 mg, 18.9 mmol) was added and the reaction further stirred at for 1 hour to complete the reaction. MeOH was concentrated and the residue diluted in CH2Cl2 and treated with aqueous 1M HCl adjusting the pH to 1. The layers were separated and the aqueous one re-extracted with CH2Cl2 (×2). The combined organic extracts were dried (Na2SO4), filtered and concentrated to give the desired compound which was used in the next step without further purification. MS (LC/MS): 263.0 [M+Na]+, 503.2 [2M+Na]+, 239.1 [M−H]−.

Provenance & Evidence