2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → Tert-butyl isopropyl(5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thiazol-2-yl)carbamate

Temperature

-78 °C

To a solution of tert-butyl 5-bromothiazol-2-yl(isopropyl)carbamate (7.5 g, 23.3 mmol) in THF (50 mL) was added n-butyllithium (1.6 M in hexane, 21.8 mL) dropwise at −78° C. The solution turned orange. The solution was stirred at −78° C. for minutes before 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (6.49 g, 34.9 mmol) was added dropwise. The mixture was stirred at −78° C. for 2 hours then warmed to room temperature. The reaction was quenched with 1:1 ammonium chloride/water (50 mL). The resulted mixture was extracted with ethyl acetate (100 mL). The organic layer was separated, washed with water, brine and concentrated. To the brown solid residue was added hexane (30 mL). The mixture was filtered and the filter cake was washed with hexane (20 mL) and dried to give as a yellow solid (4.17 g, 48% yield). LCMS (Conditions C): 3.21 min (RT); (M+H)+=247.12 (40%), 245.12 (50%), 233.10 (75%), 231.10 (100%). 1H NMR, 400 MHz, CDCl3: δ 7.95 (s, 1 H), 5.37 (m, 1 H), 1.60 (s, 9 H), 1.44 (d, 6.7 Hz, 6 H), 1.34 (s, 12 H).

1. additionwas added dropwise
2. temperaturethen warmed to room temperature
3. customThe reaction was quenched with 1:1 ammonium chloride/water (50 mL)
4. extractionThe resulted mixture was extracted with ethyl acetate (100 mL)
5. customThe organic layer was separated
6. washwashed with water, brine
7. concentrationconcentrated
8. additionTo the brown solid residue was added hexane (30 mL)
9. filtrationThe mixture was filtered
10. washthe filter cake was washed with hexane (20 mL)
11. customdried

ORD record

ord-fdcfbd0eed164943ac9592b50ea90cd0

Source dataset

uspto-grants-2013_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08410128B2