Benzene → 2-(S)-amino-3-methyl-1-phenyl-1-pentanone hydrochloride

To a stirred suspension of phosphorus pentachloride (31.4 g, 0.151 mmol.) in anhydrous benzene (300 mL) was added L-isoleucine (19.67 g, 0.151 mmol.) under chilling with ice. The mixture was then stirred for 2 hours under chilling with ice, and further stirred for 17 hours at room temperature. The reaction mixture was chilled with ice and anhydrous aluminum chloride (60 g) was portionwise added. The mixture was then slowly heated to reflux temperature for a period of 2 hours. The mixture was refluxed for 3 hours, and then chilled with ice. The chilled reaction mixture was slowly added to a mixture of concentrated hydrochloric acid (45 mL) and ice (0.3 kg). The resulting mixture was stirred at 5° C. for 40 min. The precipitated crystals were collected by filtration and washed with benzene The washed crystals were dried in air to give 2-(S)-amino-3-methyl-1-phenyl-1-pentanone hydrochloride as a white crystalline product (29.2 g, yield: 85%).

1. temperatureunder chilling with ice
2. temperatureunder chilling with ice
3. stirringfurther stirred for 17 hours at room temperature
4. additionwas portionwise added
5. temperatureThe mixture was then slowly heated
6. temperatureto reflux temperature for a period of 2 hours
7. temperatureThe mixture was refluxed for 3 hours
8. temperaturechilled with ice
9. customThe chilled reaction mixture
10. stirringThe resulting mixture was stirred at 5° C. for 40 min
11. filtrationThe precipitated crystals were collected by filtration
12. washwashed with benzene The washed crystals
13. customwere dried in air

ORD record

ord-f0288cd03552499ea1b773b87316d446

Source dataset

uspto-grants-2002_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06387908B1