Sodium Hydroxide → 3-Aminoazepan-2-one hydrochloride

A stirred mixture of L-lysine hydrochloride 1 (55 g, 300 mmol) and NaOH (12 g, 300 mmol) in hexanol (1.2 L) is heated to reflux with a Dean-Stark trap used to remove H2O. The suspension is refluxed for 8 hours until all starting material is consumed (which maybe determined by 1H NMR). The suspension is then cooled and filtered to remove byproduct NaCl. The filtrate is concentrated and the resulting crude α-amino-ε-caprolactam 2 is dissolved in water. After acidification to pH 6 with addition of concentrated HCl and partial concentration, crystals maybe formed at room temperature to afford α-amino-ε-caprolactam hydrochloride (37 g) in 75% yield.

1. temperatureis heated
2. temperatureto reflux with a Dean-Stark trap
3. customto remove H2O
4. temperatureThe suspension is refluxed for 8 hours until all starting material
5. customis consumed (which
6. temperatureThe suspension is then cooled
7. filtrationfiltered
8. customto remove byproduct NaCl
9. concentrationThe filtrate is concentrated
10. dissolutionthe resulting crude α-amino-ε-caprolactam 2 is dissolved in water
11. additionAfter acidification to pH 6 with addition of concentrated HCl and partial concentration, crystals
12. custommaybe formed at room temperature

ORD record

ord-406881e1142d452db4638f84ccb7b139

Source dataset

uspto-grants-2011_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07977450B2