反应详情

Benzyl bromide (0.13 mL, 1.1 mmol) was added to a stirred suspension of ethyl 1-{2-[(tert-butoxycarbonyl)amino]ethyl}-3-hydroxy-1H-pyrazole-5-carboxylate (0.3 g, 1 mmol) and Cs2CO3 (0.65 g, 2 mmol) in ACN (5 mL). The mixture was stirred at room temperature for 16 hours and the solvents were evaporated in vacuo. The crude product was diluted with water and extracted with AcOEt. The organic layer was separated, dried (Na2SO4), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; AcOEt in heptane 0/100 to 50/50). The desired fractions were collected and the solvents evaporated in vacuo to yield ethyl 3-(benzyloxy)-1-{2-[(tert-butoxycarbonyl)amino]ethyl}-1H-pyrazole-5-carboxylate (0.29 g, 73% yield) as a colorless oil.

1. customthe solvents were evaporated in vacuo
2. additionThe crude product was diluted with water
3. extractionextracted with AcOEt
4. customThe organic layer was separated
5. dry with materialdried (Na2SO4)
6. filtrationfiltered
7. customthe solvents evaporated in vacuo
8. customThe crude product was purified by flash column chromatography (silica; AcOEt in heptane 0/100 to 50/50)
9. customThe desired fractions were collected
10. customthe solvents evaporated in vacuo