2-Bromothiazole → tert-butyl N-[4-oxo-4-(1,3-thiazol-2-yl)butyl]carbamate

Temperature

-70 °C

A solution of 2-bromothiazole (3.6 g) in dry tetrahydrofuran (100 ml) was cooled to −78° C. under an atmosphere of nitrogen. A 2.5M solution of n-butyllithium in hexane (8.8 ml) was added dropwise over 15 minutes maintaining the temperature below −60° C. The product from step (a) (2.46 g) in tetrahydrofuran (20 ml) was then added over 15 minutes again keeping the temperature below −60° C. The reaction mixture was then maintained at −70° C. for 1 h, then allowed to warm to −10° C. over 1.5 h. The reaction mixture was then partitioned between 10% ammonium chloride solution and ethyl acetate and the resulting colloid was filtered through celite. The organic extracts were dried over magnesium sulfate, filtered and the filtrate evaporated. The resulting dark brown oil was purified by flash chromatography, eluting with hexane:ethyl acetate (2:1) to give the subtitle compound as a pale yellow oil (0.9 g, 15%).

1. temperaturemaintaining the temperature below −60° C
2. customthe temperature below −60° C
3. temperatureto warm to −10° C. over 1.5 h
4. customThe reaction mixture was then partitioned between 10% ammonium chloride solution and ethyl acetate
5. filtrationthe resulting colloid was filtered through celite
6. dry with materialThe organic extracts were dried over magnesium sulfate
7. filtrationfiltered
8. customthe filtrate evaporated
9. customThe resulting dark brown oil was purified by flash chromatography
10. washeluting with hexane:ethyl acetate (2:1)

ORD record

ord-ba2e31896edd4c53a83639017a196b0b

Source dataset

uspto-grants-2004_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06743939B2