4-Chloro-1,2-diaminobenzene → (5R)-5-benzyl-5-(6-chloro-1H-benzimidazol-2-yl)-3-[(1R)-1-phenylethyl]imidazolidine-2,4-dione

Participants

Reaction Conditions

Reaction Steps

To the product from Step D (200 mg, 0.581 mmol), 4-chlorobenzene-1,2-diamine (91 mg, 0.639 mmol) in N,N-dimethylformamide (2.5 ml) was added N,N-diisopropylethylamine (0.152 mL, 0.871 mmol) and O-(7-azabensotriazol-1yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (265 mg, 0.697 mmol) sequentially. The reaction mixture was stirred for 16 h, diluted with ethyl acetate (50 mL), washed with water (2×10 mL), saturated aqueous brine (1×10 mL), dried with anhydrous sodium sulfate, filtered and the solvent removed in vacuo. LC/MS 463.0 (M+1). The crude residue was dissolved in acetic acid (5 ml) and heated at 80° C. for 1 h. The mixture was cooled and the solvent removed in vacuo. The residue was purified by column chromatography (silica gel 40 g column) eluting with ethyl acetate/hexane (gradient from 0% to 100%) to give a mixture of diastereomers as a brown amorphous solid. The isomers were separated via chiral HPLC (ChiralPak AS-H; 40% 2:1 methanol:acetonitrile/carbon dioxide) to afford the first eluting isomer (5R)-5-benzyl-5-(6-chloro-1H-benzimidazol-2-yl)-3-[(1R)-1-phenylethyl]imidazolidine-2,4-dione (1.9 minutes) and the second eluting isomer (5S)-5-benzyl-5-(6-chloro-1H-benzimidazol-2-yl)-3-[(1R)-1-phenylethyl]imidazolidine-2,4-dione (2.97 minutes) as colorless amorphous solids. LC/MS 445.0 (M+1). IC50 value=C rating

Provenance & Evidence