Lithium diisopropylamide → Diethyl 2-(5-amino-2-(4-methoxy-2-methylphenethyl)benzo[f][1,7]naphthyridin-8-yl)-1,1-difluoro-2-hydroxyethylphosphonate

Participants

Reaction Conditions

Reaction Steps

To a solution of diethyl difluoromethylphosphonate (3.0 equiv.) in THF (0.3 M) at −78° C. under nitrogen atmosphere was added dropwise 2M LDA (3.0 equiv., commercial grade). The reaction was stirred at −78° C. for 25 min, and a solution of 5-amino-2-(4-methoxy-2-methylphenethyl)benzo[f][1,7]naphthyridine-8-carbaldehyde (2-2) (1.0 equiv.) in THF (0.1 M) was added slowly. The reaction was stirred at −78° C. for 1 hour, 0° C. for 1 hour, and then warmed to room temperature over 30 minutes. The reaction was quenched with saturated aqueous ammonium chloride solution and extracted twice with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous MgSO4, and concentrated in vacuo. The resulting residue was purified by a COMBIFLASH® system (ISCO) using a gradient of 0-5% MeOH/DCM to provide diethyl 2-(5-amino-2-(4-methoxy-2-methylphenethyl)benzo[f][1,7]naphthyridin-8-yl)-1,1-difluoro-2-hydroxyethylphosphonate (2-3) as a solid.

Provenance & Evidence