Cesium carbonate → (S)-tert-butyl (1-((6-cyclopropyl-5-oxo-5,6-dihydrobenzo[c][2,7]naphthyridin-8-yl)oxy)-4-methylpentan-2-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a solution 8-chloro-6-cyclopropylbenzo[c][2,7]naphthyridin-5(6H)-one (200 mg, 0.739 mmol) in toluene (2 mL) at room temperature was added cesium carbonate (361 mg, 1.108 mmol) and di-tert-butyl(2′,4′,6′-triisopropyl-[1,1′-biphenyl]-2-yl)phosphine (188 mg, 0.443 mmol) and the mixture was degassed with nitrogen for 5 min. The mixture was then treated with N-Boc-L-leucinol (477 mg, 2.216 mmol) followed by palladium(II)acetate (49.8 mg, 0.222 mmol) and degassed for another 10 min. The reaction mixture was sealed and heated at 80° C. After overnight stirring the reaction mixture was cooled to room temperature and filtered through diatomaceous earth (Celite®). The bed was washed with ethyl acetate and the combined filtrate was concentrated under reduced pressure to afford crude product which was purified by combi flash (ethyl acetate and petroleum ether) to afford (S)-tert-butyl (1-((6-cyclopropyl-5-oxo-5,6-dihydrobenzo[c][2,7]naphthyridin-8-yl)oxy)-4-methylpentan-2-yl)carbamate (100 mg, 0.195 mmol, 26% yield) as an off-white solid. LC/MS (ESI) m/e 452.2 [(M+H)+, calcd for C26H34N3O4 452.3]; LC/MS retention time (method C): tR=2.11 min.

Provenance & Evidence