Into a 10 mL round-bottom flask was placed a solution of compound 90j (150 mg, 0.300 mmol) in DMF (2 mL), followed by the addition of sodium hydride (30.0 mg, 1.25 mmol) at 0° C. The mixture was stirred for 15 min at 0° C., and 2-chloroquinoline (74.2 mg, 0.460 mmol) was added. The reaction mixture was stirred overnight at 70° C. Upon cooling, the reaction was quenched with water. The resulting mixture was extracted with DCM (3×10 mL). The combined organic layers were concentrated under reduced pressure. The resultant residue was purified by flash column chromatography on silica gel (EtOAc/petroleum ether (1:3 v/v)) to obtain compound 91a as a light yellow solid (130 mg, 69% yield). Mass Spectrum (LCMS, ESI pos.): Calcd. for C35H39N7O4: 622.3 (M+H). found: 622.2.
