Hydrochloric Acid → Diethyl (1S,2S,5R,6S)-2-aminospiro[bicyclo[3.1.0]hexane-4,1'-cyclopropane]-2,6-dicarboxylate hydrochloride

Participants

Reaction Conditions

Reaction Steps

Charge absolute ethanol (100 mL, 10 volumes), concentrate. HCl (2.1 mL, 1.0 N) and diethyl (1S,2S,5R,6S)-2-benzyloxycarbonylaminospiro[bicyclo[3.1.0]hexane-4,1′-cyclopropane]-2,6-dicarboxylate (9.7 g, 24.16 mmol) to a HEL reactor followed by Pd black (3.9 g, 40 wt %). Purge the reactor three times with nitrogen followed by three hydrogen purges and pressurization to 40 psi hydrogen. Allow the reaction to stir between 20-30° C. for at least two hours until the completion of the reaction monitored by HPLC. Filter the resulting slurry through a pad of Hyflo Super Cel® and wash the wet cake with absolute ethanol (2×30 mL, 3 volumes). Transfer the filtrate to a clean reactor and displace ethanol with isopropyl acetate to approximately 5 volumes based on in-situ product yield from calibration curve. Cool the resulting slurry to 0-5° C. over at least 3 hours. Filter the resulting slurry and wash the wet cake washed with cold isopropyl acetate (3×5 mL, 0.5 volumes). Dry under reduced pressure at 30° C. for at least 12 hours to provide the title compound (4.66 g, 15.34 mmol 63.5%) 1H NMR (DMSO-d6, 400 MHz): δ 8.84 (s, 3H), 4.31-4.15 (m, 2H), 4.03 (q, J=7.0, 2H), 2.42 (dd, J=3.1, 2.6, 1H), 2.24 (dd, J=6.2, 2.6, 1H), 1.94 (d, J=14.1, 1H), 1.68 (d, J=14.1, 1H), 1.63 (dd, J=6.6, 3.1, 1H), 1.25 (t, J=7.0, 3H), 1.17 (t, J=7.0, 3H), 0.77-0.71 (m, 1H), 0.65-0.59 (m, 1H), 0.56-0.51 (m, 1H), 0.50-0.44 (m, 1H).

Provenance & Evidence