Sodium borohydride → tert-Butyl 6-amino-1H-indole-1-carboxylate

To a stirring solution of 1-Boc-6-nitroindole (250 mg, 0.95 mmol) in THF (5 mL) and MeOH (10 mL) at 0° C., was added Ni(OAc)2.4H2O (473 mg, 1.9 mmol). After complete dissolution, NaBH4 (143 mg, 3.8 mmol) was added slowly. Upon addition of the NaBH4, the reaction mixture turned black and vigorous gas evolution was observed. After 15 min, the solvents were removed in vacuo and the residue was dissolved in a stirring mixture of ethyl acetate (100 mL), conc NH4OH (10 mL) and water (20 mL). The layers were separated and the organic phase was washed again with 33% conc NH4OH in water and then washed twice with brine. The organic phase was then dried with MgSO4, filtered and concentrated in vacuo.

1. additionwas added slowly
2. customthe solvents were removed in vacuo
3. dissolutionthe residue was dissolved in a stirring mixture of ethyl acetate (100 mL), conc NH4OH (10 mL) and water (20 mL)
4. customThe layers were separated
5. washthe organic phase was washed again with 33% conc NH4OH in water
6. washwashed twice with brine
7. dry with materialThe organic phase was then dried with MgSO4
8. filtrationfiltered
9. concentrationconcentrated in vacuo

ORD record

ord-438b2cfcf6c846a2bd0508aa1813fe2b

Source dataset

uspto-grants-2002_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06372759B1