ORGANIC SPECTROSCOPY INTERNATIONAL: (S)-tert-Butyl 2-(Benzylcarbamoyl)pyrrolidine-1-carboxylate

BOC -L- PROLINE+ BENZYL AMINE=(S)-tert-Butyl 2-(Benzylcarbamoyl)pyrrolidine-1-carboxylate

(S)-tert-Butyl 2-(Benzylcarbamoyl)pyrrolidine-1-carboxylate

IR (neat) 3310, 2976, 2871, 1682, 1652, 1526, 1393, 1370, 1157, 1127, 766, 724, 693 cm^-1.

MP 124-125 °C.

¹H NMR pdf (600 MHz, d-6 DMSO) Major rotamer δ: 1.28 (s, 6 H), 1.41 (s, 3 H), 1.67 - 1.90 (m, 3 H), 2.04 - 2.18 (m, 1 H), 3.25 - 3.32 (m, 1 H), 3.36 - 3.43 (m, 1 H), 4.08 (dd, J = 8.6, 3.1 Hz, 1 H), 4.21 (dd, J = 14.0, 5.9 Hz, 1 H), 4.34 (dd, J = 14.0, 5.9 Hz, 1 H), 7.20-7.34 (m, 5 H), 8.39 (t, J = 5.9 Hz, 1 H).

Minor rotamer δ: 1.28 (s, 6 H), 1.41 (s, 3 H), 1.67 - 1.90 (m, 3 H), 2.04 - 2.18 (m, 1H), 3.25 - 3.32 (m, 1 H), 3.36 - 3.43 (m, 1 H), 4.12 (dd, J = 8.6, 3.1 Hz, 1 H), 4.19 (dd, J = 14.0, 5.9 Hz, 1 H), 4.34 (dd, J = 14.0, 5.9 Hz, 1 H), 7.20-7.34 (m, 5 H), 8.34 (t, J = 5.9 Hz, 1 H).

¹H NMR (600 MHz, DMSO, 60 °C) δ: 1.29 (s, 9 H), 1.67 - 1.91 (m, 2 H), 1.99 - 2.20 (m, 1 H), 3.29 (dt, J = 10.5, 6.8 Hz, 1 H), 3.38 (ddd, J = 10.5, 7.5, 5.1 Hz, 1 H), 4.10 (s, 1 H), 4.21 (dd, J = 14.9, 6.0 Hz, 1 H), 4.31 (dd, J = 14.9, 6.0 Hz, 1 H), 7.20 (t, J = 6.8 Hz, 1 H), 7.23 - 7.31 (m, 4 H), 8.16 (s, 1 H).

¹³C NMR pdf (150 MHz, d-6 DMSO) Major rotamer δ: 23.6, 28.4, 31.6, 42.5, 47.0, 60.4, 78.9, 127.8, 128.6, 140.1, 153.8, 172.9;

Minor rotamer δ: 24.5, 28.66, 30.5, 42.3, 47.2, 60.3, 79.1, 127.0, 127.19, 127.3, 140.1, 154.2, 172.7.

HRMS m/z calcd for C₁₇H₂₅N₂O₃[M + H]⁺: 305.1860; Found: 305.1856. Anal. calcd for C₁₇H₂₄N₂O₃: C, 67.08; H, 7.95; N, 9.20; Found: C, 67.02; H, 7.89; N, 9.04.

Chiral HPLC AD-H column, 90:10 isohexane:2-PrOH, flow 0.7 mL/min, 30 °C, retention time 18.54 min (Retention times for racemic sample = 7.16 min and 19.93 min).