Imidazole → (S)-(2-Iodo-1-methyl-ethyl)-carbamic acid tert-butyl ester

Temperature

0 °C

PS-triphenylphosphine (2.5 mmol/g, 1.3 g, 3.3 mmol) was suspended in methylene chloride (12 mL). Imidazole (225 mg, 3.3 mmol) was added and the mixture was cooled to 0° C. in an ice-water bath. To the cooled mixture was added iodine (838 mg, 3.3 mmol), and the resulting mixture was warmed to room temperature, stirred 10 minutes and recooled to 0° C. Boc-L-alaninol (463 mg, 2.64 mmol) in methylene chloride (3 mL) was added over several minutes. The resulting mixture was stirred at 0° C. for 1 hour, warmed to room temperature and stirred 2 h. The mixture was filtered. The solids collected were washed thoroughly with ethyl acetate. The filtrate washed with dilute aqueous HCl (3%), sodium thiosulfate (1 M), saturated aqueous sodium bicarbonate and brine. The extracts were then dried over magnesium sulfate, filtered and concentrated under reduced pressure. The crude tert-butyl [(1S)-2-iodo-1-methylethyl]carbamate (xxvii) was obtained as a yellow oil and used without further purification. 1H NMR (300 MHz, CDCl3): δ 3.34-3.56 (m, 2H), 3.27 (dd, J=3.7, 9.8 Hz, 1H), 1.43 (s, 9H), 1.18 (d, J=6.7 Hz, 3H).

1. temperaturethe resulting mixture was warmed to room temperature
2. customrecooled to 0° C
3. stirringThe resulting mixture was stirred at 0° C. for 1 hour
4. temperaturewarmed to room temperature
5. stirringstirred 2 h
6. filtrationThe mixture was filtered
7. customThe solids collected
8. washwere washed thoroughly with ethyl acetate
9. washThe filtrate washed with dilute aqueous HCl (3%), sodium thiosulfate (1 M), saturated aqueous sodium bicarbonate and brine
10. dry with materialThe extracts were then dried over magnesium sulfate
11. filtrationfiltered
12. concentrationconcentrated under reduced pressure

ORD record

ord-a5fc0d0c8c6540c292140d8b1598f130

Source dataset

uspto-grants-2010_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07812018B2