反应详情

Reduction of nitro group to amine group used one of the following methods. Method A: Nitro indole 2-oxoacetyl amide and catalytic amount of palladium on carbon (Pd—C) was mixed in EtOH. The mixture was hydrogenated using Parr reactor under hydrogen pressure of 40-50 psi at room temperature for 24 hours. Then, solid was removed via filtration and filtrate was concentrated under vacuum to give crude amino indole 2-oxoacetyl amide which could be used as was or purified by silica gel chromatography. Method B: An excess of Fe (10-50 eq.) was added into the solution of nitro indole 2-oxoacetyl amide in saturated aqueous NH4Cl-EtOH (volume 1:1). The mixture was stirred at room temperature to 115° C. for 24 hours to 3 days. Solid was removed via filtration and solvents were removed under vacuum. Then, the residue was partitioned between water and EtOAc (equal volume to solvents used in reaction). The aqueous phase was extracted with EtOAc (3×e equal volume to solvents used in reaction). The combined organic phase was dried over MgSO4, filtered and concentrated under vacuum to give a crude amino indole 2-oxoacetyl amide which could be used as was or purified by silica gel chromatography.

1. custompurified by silica gel chromatography
2. customSolid was removed via filtration and solvents
3. customwere removed under vacuum
4. customThen, the residue was partitioned between water and EtOAc (equal volume to solvents used in reaction)
5. extractionThe aqueous phase was extracted with EtOAc (3×e equal volume to solvents used in reaction)
6. dry with materialThe combined organic phase was dried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated under vacuum