3-(2-Nitrophenoxy)benzonitrile → 3-(2-Aminophenoxy)benzonitrile

Participants

Reaction Steps

To a solution of 2-fluoro nitrobenzene (1.41 g, 10 mmol, 1.0 equiv) and 3-hydroxybenzonitrile (1.19 g, 1.0 equiv) in 10 mL of DMF was added K2CO3 (2.76 g, 2 equiv). After stirring at 60° C. for 3 h, the mixture was diluted with EtOAc and washed with H2O. The organic layer was dried over MgSO4, filtered and evaporated to give 3-(2-nitrophenoxy)benzonitrile (2.38 g, 99%). MS found for C13H9N2O3 (M+H)+: 241. Step 2: A solution of 3-(2-nitrophenoxy)benzonitrile (1.21 g, 5 mmol, 1.0 equiv) in 30 mL of EtOH was treated with SnCl22H2O (3.38 g, 3 equiv) at reflux for 4 h. The volatile was evaporated and the residue was redissolved in EtOAc, washed with saturated aqueous NaHCO3 and 1N NaOH. The organic layer was dried over MgSO4, filtered and evaporated to give 3-(2-aminophenoxy)benzonitrile (1.04 g, 99%). MS found for C13H11N2O (M+H)+: 211. Step 3: A mixture of 3-(2-aminophenoxy)benzonitrile (210 mg, 1 mmol, 1.0 equiv), 4-[(2-t-butylaminosulfonyl)phenyl]benzoic acid (330 mg, 1 equiv), Bop reagent (880 mg, 2 equiv) and TEA (1.39 mL, 10 equiv) in 3 mL of DMF was stirred at rt overnight. The mixture was diluted with EtOAc, washed with H2O. The organic layer was dried over MgSO4, filtered and evaporated. Flash chromatography on silica gel gave 3-(2-(4-[(2-t-butylaminosulfonyl)phenyl]benzoylamino)phenoxy)benzonitrile (300 mg, 57%). MS found for C30H28N3O4S (M+H)+: 526. Step 4: A stream of HCl(g) was bubbled through a 0° C. solution of 3-(2-(4-[(2-t-butylaminosulfonyl)phenyl]benzoylamino)phenoxy)benzonitrile (53 mg, 0.1 mmol) in 5 mL of methanol until saturation. The mixture was stirred at rt overnight and evaporated. The resulting residue was treated with ammonium acetate (39 mg, 5 equiv) in 10 ml methanol at reflux temperature for 2 h. The solvent was removed at reduced pressure and the crude benzamidine was purified by HPLC (C18 reversed phase) eluting with 0.5% TFA in H2O/CH3CN to give 3-(2-(4-[(2-aminosulfonyl)phenyl]benzoylamino)phenoxy)benzamidine (40 mg, 83%). MS found for C26H23N4O4S (M+H)+: 487.

Provenance & Evidence