Diphenyl carbonate → phenyl 6-bromo-7-(dimethoxymethyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate

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Reaction Steps

A solution of 6-bromo-7-(dimethoxymethyl)-1,2,3,4-tetrahydro-1,8-naphthyridine (intermediate 12, 2.28 g, 7.94 mmol) and diphenylcarbonate (2.13 g, 9.93 mmol) in THF (40 ml) at −17° C. was treated drop wise over 5 min with LHMDS (1M in THF, 8.34 ml, 8.34 mmol). The yellow reaction mixture was stirred for 30 min, quenched with sat. aq. NH4Cl and extracted with EtOAc (2×). The combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The crude was purified by normal phase chromatography (80 g silica gel cartridge, heptanes/EtOAc 100:0 to 0:100) to give the title compound as a white solid. 1H NMR (400 MHz, DMSO-d6) δ 7.94 (s, 1H) 7.37-7.45 (m, 2H) 7.19-7.28 (m, 3H) 5.46 (s, 1H) 3.80-3.87 (m, 2H) 3.29 (s, 6H) 2.84 (t, 2H) 1.90-2.00 (m, 2H).

Provenance & Evidence