ETHYL 4-AMINO-2-ETHYLCYCLOPENTANECARBOXYLATE synthesis

Yield:1201187-14-5 99%

Reaction Conditions:

with hydrogen;Pearlman catalyst in ethanol at 50; under 1551.49 Torr; for 1.5 h;

Steps:

FF.1

A mixture of (2R,4S)-ethyl 4-amino-2-ethyl-1-methylcyclopentanecarboxylate and (2S,4R)-ethyl 4-amino-2-ethyl-1-methylcyclopentanecarboxylate (0.454 g, 2.28 mmol) was protected using General Procedure P. The crude reaction mixture was purified by silica gel chromatography eluting with a gradient of 0-25% EtOAc/heptane to afford (1S,2R,4S) and (1R,2S,4R)-ethyl 4-(tert-b toxycarbonylamino)-2-ethyl-1-methylcyclopentanecarboxylate (0.180 g, 26%): ¹H NMR (400 MHz, CDCl₃) δ 4.46 (s, 1H), 4.12 (q, J=7.1 Hz, 2H), 4.07-3.93 (m, 1H), 2.65 (dd, J=9.2, 13.8 Hz, 1H), 2.36 (s, 1H), 2.24-2.08 (m, 1H), 1.57 (m, 1H), 1.54-1.39 (m, 10H), 1.34-1.17 (m, 4H), 1.17-1.05 (m, 4H), 0.87 (t, J=7.4 Hz, 3H), (1R,2R,4S) and (1S,2S,4R)-ethyl 4-(tert-butoxycarbonylamino)-2-ethyl-1-methylcyclopentanecarboxylate (0.430 g, 63%): ¹H NMR (400 MHz, CDCl₃) δ 5.18 (s, 1H), 4.24-4.04 (m, 3H), 2.46-2.33 (m, 1H), 1.97 (m, 2H), 1.63-1.50 (m, 2H), 1.48-1.34 (m, 9H), 1.3-1.17 (m, 7H), 1.04-0.92 (m, 1H), 0.89 (t, J=7.1 Hz, 3H).

References:

US2009/312338,2009,A1 Location in patent:Page/Page column 125