Cesium carbonate → tert-butyl (1-((5H-chromeno[3,4-c]pyridin-8-yl)oxy)-4-methylpentan-2-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

To 8-chloro-5H-chromeno[3,4-c]pyridine (0.489 g, 2.247 mmol) (prepared as in Example 5, Part D), (S)-tert-butyl (1-hydroxy-4-methylpentan-2-yl)carbamate (1.474 g, 6.79 mmol), di-tert-butyl(2′,4′,6′-triisopropyl-[1′,1′-biphenyl]-2-yl)phosphine (0.572 g, 1.348 mmol), palladium (II) acetate (0.151 g, 0.674 mmol) and cesium carbonate (1.098 g, 3.37 mmol) was added toluene (4 mL). Nitrogen gas was bubbled through the mixture for 5 min and the mixture heated at 80° C. for 15 h. The reaction mixture was cooled to room temperature and filtered through a bed of celite. Water (10 mL) was added to the filtrate and the product was extracted with ethyl acetate (3×15 mL). The combined organic extracts were washed with brine (1×10 mL), dried with sodium sulfate and concentrated under reduced pressure. The residue so obtained was purified by preparative TLC using (50% ethyl acetate in pet ether) to afford tert-butyl (1-((5H-chromeno[3,4-c]pyridin-8-yl)oxy)-4-methylpentan-2-yl)carbamate (0.4 g, 1.00 mmol, 45% yield) as a semi solid. LCMS (ESI) m/e 399.2 [(M+H)1, calcd for C23H31N2O4 399.5]; LC/MS retention time (Method C): tR=2.16 min.

Provenance & Evidence