Diethyl Carbonate → tert-butyl 7-(2-ethoxy-2-oxoethyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate

Participants

Reaction Steps

To a solution of diisopropylamine (7.24 mL, 55.3 mmole) in dry TBF (50 mL) was added n-BuLi (2.5 M in hexanes, 22 mL, 55.3 mmole) dropwise at 0° C. After 15 min, this solution was added dropwise to a solution of 2-methyl-8-(tert-butoxycarbonyl)-5,6,7,8-tetrahydro-1,8-naphthyridine (4.9 g, 19.7 mmole) and diethylcarbonate (8.86 mL, 73.0 mmole) in dry THF (50 mL) at −78° C. After 30 min, the mixture was quenched with saturated NH4Cl (100 mL), warmed to RT, and extracted with EtOAc (3×200 mL). The combined organic extracts were dried over MgSO4, filtered, and concentrated under reduced pressure. The residue was chromatographed on silica gel (40% EtOAc/hexanes) to give the title compound (5.72 g, 91%) as a light yellow oil: MS (ES) m/e 321 (M+H)+.

Provenance & Evidence