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 liter 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-1b87cd17b096487b82eaf832b5cca590

Source dataset

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08350052B2