1-Bromopropane → HCID 60098517, compound

n-Propyl bromide (0.17 ml, 1.85 mmol) was added to a mixture of Nα-Boc-L-histidine methyl ester (500 mg, 1.85 mmol) and potassium carbonate (200 mg, 1.85 mmol) in acetonitrile (20 ml), and the mixture was heated under reflux for 18 hours. TLC analysis showed starting material remaining, so additional n-propyl bromide (0.17 ml, 1.85 mmol) and potassium carbonate (200 mg, 1.85 mmol) were added, and the mixture was heated for a further 8 hours. The cooled, mixture was concentrated under reduced pressure. The residue was dissolved in water and the solution was extracted with ethyl acetate (3×20 ml). The combined organic extracts were washed with brine (3×20 ml), dried (Na2SO4) and evaporated under reduced pressure. The residual orange oil was purified by column chromatography on silica gel using an elution gradient of hexane:ethyl acetate (100:0 to 0:100) to afford the title compound as a colourless oil, 200 mg. 1H-NMR (CDCl3, 300 MHz) δ: 0.90 (t, 3H), 1.42 (s, 9H), 1.78 (m, 2H), 3.03 (m, 2H), 3.68 (s, 3H), 3.80 (t, 2H), 4.56 (m, 1H), 5.92 (m, 1H), 6.65 (s, 1H), 7.37 (s, 1H). LRMS: m/z (TSP+) 312.2 (MH+).

1. temperaturethe mixture was heated
2. temperatureunder reflux for 18 hours
3. temperaturethe mixture was heated for a further 8 hours
4. concentrationThe cooled, mixture was concentrated under reduced pressure
5. dissolutionThe residue was dissolved in water
6. extractionthe solution was extracted with ethyl acetate (3×20 ml)
7. washThe combined organic extracts were washed with brine (3×20 ml)
8. dry with materialdried (Na2SO4)
9. customevaporated under reduced pressure
10. customThe residual orange oil was purified by column chromatography on silica gel using an elution gradient of hexane:ethyl acetate (100:0 to 0:100)

ORD record

ord-474ab426b29346478f923573aedfa51c

Source dataset

uspto-grants-2005_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06919457B2