Water → (-)-(1S,4R)-4-Amino-2-cyclopentene-1-carboxylic acid methanesulfonate

Participants

Reaction Conditions

Reaction Steps

A solution of (-)-2-azabicyclo[2.2.1]hept-5-en-3-one (97.45 g, 0.8929 mol, Enzymatix Ltd.) in tetrahydrofuran (500 mL) was filtered and warmed to 35° C. A solution of methanesulfonic acid (63.7 mL, 0.9817 mol) in water (24.1 mL, 1.34 mol) was added over the course of 1.5 hours such that the ensuing exotherm did not exceed 45° C. The resulting slurry was heated at 60° C. for three hours, then allowed to cool to room temperature over the course of 15 hours. The slurry was filtered and the cake washed twice with anhydrous tetrahydrofuran (200 mL). An analytical sample of the wet cake was removed and dried to give the title compound as a white solid (1.264 g); m.p. 167°-169.2° C.; 1H-NMR (DMSO-d6)δ: 12.6 (br s, 1H, CO2H), 8.04 (br s, 3H, NH3+), 6.10 (dr, J=5.6, 2.0, 2.0 Hz, 1H, vinyl), 5.85 (dt, J=5.3, 2.3, 2.3Hz, 1H, vinyl), 4.19 (br s, w1/2=20Hz, 1H, allylic H), 3.61 (m, w1/2=22Hz, 1H, allylic H), 2.53 (quintet, J=5.3 Hz (overlapping with DMSO peak), 1/2CH2), 2.39 (s, 3H, CH3SO3H), 1.93 (dt, J=6.7, 6.7, 13.7 Hz, 1H, 1/2CH2); [α]20589 -83.8°, [α]20578 -87.4°, [α]20546 -101.2°, [α]20436 -186.7°, [α]20365 -316.2° (c=1.42, methanol); CI-MS (CH4): 128(M+1); EI-MS: 127(M).

Provenance & Evidence