6-Aminohexanoic Acid → Ethyl 6-aminohexanoate

Participants

Reaction Steps

A mixture of ε-aminocaproic acid (70.0 g, 533.8 mmol), toluenesulfonic acid (111.7 g, 1.1 eq.) and ethanol (1.6 L) was heated to reflux for 20 hours. Thereafter, TLC (CH2Cl2/EtOH/TEA, 85:10:5) revealed complete conversion. The reaction mixture was concentrated until solids started to precipitate. The precipitation was driven to completion by adding diethyl ether (1.5 L). The white solid was filtered, washed with diethyl ether, and dried in vacuo affording 174.0 g (98.3%) of a white powder. 1H NMR: (200 MHz, CDCl3): δ 7.47 (d, 2H, J=8.2 Hz), 7.10 (d, 2H, J=8.2 Hz), 4.02 (q, J=7.0 Hz), 2.79-2.65 (m, 2H), 2.28 (s, 3H), 2.25 (t, 2H, J=7.0 Hz), 1.16 (t, 3H, J=7.0 Hz), 1.49 (dt, 4H, J=7.6, 7.0 Hz), 1.29-1.22 (m, 2H). 13C NMR: 173.4, 145.6, 138.8, 128.9, 126.1, 60.4, 39.4, 33.9, 27.3, 25.9, 24.6, 21.5, 14.8.

Provenance & Evidence