Cesium carbonate → (S)-tert-butyl (1-((6,9-dimethyl-5-oxo-5,6-dihydrobenzo[c][2,7]naphthyridin-8-yl)oxy)-4-methylpentan-2-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

In a 10 mL round-bottomed flask, (S)-tert-butyl (1-((9-bromo-6-methyl-5-oxo-5,6-dihydrobenzo[c][2,7]naphthyridin-8-yl)oxy)-4-methylpentan-2-yl)carbamate (as prepared in Ex. 3, Part A) (150 mg, 0.297 mmol), 2,4,6-trimethyl-1,3,5,2,4,6-trioxatriborinane (41.1 mg, 0.327 mmol), Cs2CO3 (291 mg, 0.892 mmol) and PdCl2(dppf) (21.76 mg, 0.030 mmol) were taken up in a mixture of 1,4-dioxane (2 mL) and water (0.1 mL). The reaction mixture was purged with nitrogen for 5 min and heated at 90° C. for 15 h. 1,4-dioxane was removed under reduced pressure and the residue was dissolved in ethyl acetate (20 mL). The ethyl acetate layer was washed with water (10×2 mL) and dried over sodium sulfate. Removal of the solvent gave crude product (0.08 g), which was filtered through silica-gel column (24 g silica-gel, MeOH—CHCl3 mixture). The product was isolated as off-white solid (0.05 g, 0.11 mmol, 38% yield). LC/MS (ES-API) m/e 440.2 [(M+H)+, calcd for C25H34N3O4, 440.3]; LC/MS retention time (method B): tR=1.95 min.

Provenance & Evidence