N-Cyclopentyl-ethane-1,2-diamine synthesis

Yield:41062-14-0 35%

Reaction Conditions:

with sodium cyanoborohydride;acetic acid in methanol; for 48 h;Molecular sieve;

Steps:

122 Preparation 122
N1-Cyclopentylethane-1,2-diamine

Preparation 122
N1-Cyclopentylethane-1,2-diamine
To a solution of cyclopentanone (2.000 mL, 22.6 mmol), ethylenediamine (10.860 g, 180.7 mmol), acetic acid (10.345 mL, 180.7 mmol), and 4 {acute(?)} molecular sieves (10 g) in anhydrous methanol (113 mL) was added sodium cyanoborohydride (2.839 g, 45.2 mmol).
The mixture was stirred for 48 hrs, filtered to remove the solids, and concentrated in vacuo.
The residue was dissolved in 3 N aqueous sodium hydroxide (150 mL) and extracted with methylene chloride (3*300 mL).
The combined organic layers were washed with basic saturated aqueous sodium chloride, dried (anhydrous sodium sulfate), filtered, and concentrated to give the crude product.
The material was vacuum distilled to give the desired product as a clear liquid (1.0 g, 35%).
¹H NMR (300 MHz, CDCl₃) δ 3.08-2.99 (quint, 1H, J=6.8 Hz), 2.80-2.76 (t, 2H, J=5.9 Hz), 2.65-2.61 (t, 2H, J=5.9 Hz), 1.87-1.77 (m, 2H), 1.72-1.60 (m, 2H), 1.57-1.46 (m, 2H), 1.35-1.24 (m, 5H).

References:

US2013/303524,2013,A1 Location in patent:Paragraph 0482-0483