Hydrochloric Acid → 1-benzyl-3-bromo-1H-indazole

3-bromo-1H-indazole (90.4 g, 0.459 mol, 1.0 eq.) and toluene (450 mL) were placed in a 1 litre flask fitted with a mechanical stirrer under an atmosphere of nitrogen. Then potassium t-butoxide (t-BuOK, 54.2 g, 0.483 mol, 1.05 eq.) was added at room temperature over about half an hour and benzyl bromide (86.3 g, 0.505 mol, 1.1 eq.) was added over approximately 1.5 hours. The mixture was left stirred at the same temperature until the reaction was complete (checked by TLC, approximately 3 hours). Then 0.1 M HCl (45 mL) and water (90 mL) were added and the resulting phases were separated. The organic phase was washed with water, and the solvent was evaporated off at reduced pressure in order to obtain a red oily residue. The product was then precipitated through the addition of n-heptane, filtered and dried under vacuum at room temperature. Yield: 65.9 g of beige solid (yield 50%).

1. customfitted with a mechanical stirrer under an atmosphere of nitrogen
2. waitThe mixture was left
3. custom(checked by TLC, approximately 3 hours)
4. customthe resulting phases were separated
5. washThe organic phase was washed with water
6. customthe solvent was evaporated off at reduced pressure in order
7. customto obtain a red oily residue
8. customThe product was then precipitated through the addition of n-heptane
9. filtrationfiltered
10. customdried under vacuum at room temperature

ORD record

ord-f1f1098453b84ab89e6375e365bff807

Source dataset

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08354544B2