1,1'-(9,9-Dimethyl-9H-xanthene-4,5-diyl)bis(1,1-diphenylphosphine) → tert-butyl 5-(2-oxo-1,2-dihydro-3H-imidazo[4,5-b]pyridin-3-yl)-2,3-dihydro-1H-indole-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of tert-butyl 5-amino-2,3-dihydro-1H-indole-1-carboxylate (4.10 g), tert-butyl 2-chloropyridin-3-ylcarbamate (4.20 g), Pd2(dba)3 (0.48 g), Xantphos (0.608 g), sodium tert-butoxide (2.52 g) in 2-propanol (64 ml) and toluene (12 mL) was stirred at 90° C. for 40 h, and treated with water and extracted with EtOAc. The organic layer was dried over MgSO4 and concentrated in vacuo. The residue was suspended in CH3CN and the precipitate was collected by filtration to give tert-butyl 5-(2-oxo-1,2-dihydro-3H-imidazo[4,5-b]pyridin-3-yl)-2,3-dihydro-1H-indole-1-carboxylate (1.64 g). The filtrate was evaporated and then the residue was chromatographed on silica gel eluting with AcOEt/Hexane=2/1 to afford second crop (1.4 g).

Provenance & Evidence