Hydrochloric Acid → 1071520-51-8

Temperature

25 °C

Methyl (1S,2S,3R,4R)-3-{[(benzyloxy)carbonyl]amino}bicyclo[2.2.1]hept-5-ene-2-carboxylate (1 g, 3.32 mmol) was dissolved in ethyl acetate (15 mL). 5% Palladium on carbon (120 mg) was added. The flask was degassed and backfilled with hydrogen gas via balloon. The mixture was stirred at 25° C. for 16 h. The mixture was passed through a plug of Celite and the filtrate was concentrated in vacuo to afford a thick clear oil. The oil was dissolved in diethyl ether (10 mL) and added dropwise, with vigorous stirring, to a mixture of 4.0 M hydrochloric acid solution in 1,4-dioxane (1.8 mL, 7.2 mmol) in diethyl ether (18 mL). The desired product began to precipitate as a white solid. Additional diethyl ether (10 mL) was added and the mixture was stirred for 10 min. The precipitate was collected by vacuum filtration and washed with additional diethyl ether (2×8 mL). The solid was further dried in vacuo for 1 h to afford the desired product, methyl (1R,2S,3R,4S)-3-aminobicyclo[2.2.1]heptane-2-carboxylate hydrochloride (0.554 g, 2.7 mmol, 81%), as a white powder. 1H NMR (400 MHz, DMSO-d6) δ: 1.18-1.27 (3H, m), 1.37-1.61 (2H, m), 1.90 (1H, d, J=11.0 Hz), 2.35 (1H, d, J=3.8 Hz), 2.44 (1H, d, J=3.1 Hz), 2.75 (1H, d, J=8.7 Hz), 3.29-3.34 (1H, m), 3.61 (3H, s), 8.03 (3H, bs). LC-MS (ESI) calcd for C9H15NO2 (free amine) 169.11, found 170.3 [M+H+] (100%), 339.3 [2M+H+] (50%).

1. customThe flask was degassed
2. concentrationthe filtrate was concentrated in vacuo
3. customto afford a thick clear oil

ORD record

ord-4dbc143ae6e24cc284b9832446bc2507

Source dataset

uspto-grants-2011_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07939524B2