Hydrochloric Acid → 1-[2-(1,3-Thiazol-2-yl)ethyl]piperazine

Temperature

0 °C

1-Boc-4-(2-oxo-2-thiazol-2-ylethyl)piperazine (5.0 g, 16.1 mmol) was dissolved in methanol (25 mL). To this solution, magnesium sulfate (2 g) was added, followed by p-tosylhydrazine (3.9 g, 20.2 mmol). The mixture was stirred for 48 h and then filtered, and the filtrate concentrated under vacuum. The residue (6.0 g, about 12 mmol) was redissolved in methanol (120 mL), and sodium triacetoxyborohydride (10.1 g, 48 mmol) was added. The mixture was heated to reflux overnight. The mixture was cooled to 0° C. and concentrated HCl (15 mL) slowly added. The mixture was allowed to warm to room temperature and stirred for 1 h. The mixture was concentrated to half the volume and placed on an SCX column (30 g, pretreated with 5% acetic acid in methanol) and washed with methanol (500 mL). The product was eluted with saturated ammonium hydroxide in methanol (500 mL) and the solvent removed under vacuum. The crude product was then purified by chromatography (SiO2, 12:1-4:1 CH2Cl2:CMA) to provide 1-(2-thiazol-2-ylethyl)piperazine (1.9 g, 57%).

1. filtrationfiltered
2. concentrationthe filtrate concentrated under vacuum
3. temperatureThe mixture was heated
4. temperatureto reflux overnight
5. temperatureto warm to room temperature
6. stirringstirred for 1 h
7. concentrationThe mixture was concentrated to half the volume
8. washwashed with methanol (500 mL)
9. washThe product was eluted with saturated ammonium hydroxide in methanol (500 mL)
10. customthe solvent removed under vacuum
11. customThe crude product was then purified by chromatography (SiO2, 12:1-4:1 CH2Cl2:CMA)

ORD record

ord-72ed84466b784770ab09fe3dcee860c4

Source dataset

uspto-grants-2005_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06946467B2