8-Hydroxyquinoline → tert-Butyl 6-(4-(benzyloxy)-2-oxopyridin-1(2H)-yl)-9-methyl-3,4-dihydro-1H-pyrido[3,4-b]indole-2(9H)-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of tert-Butyl-6-bromo-9-methyl-3,4-dihydro-1H-pyrido[3,4-b]indole-2(9H)-carboxylate (750 mg, 2.03 mmol) in DMSO (10 mL) was stirred under nitrogen and treated sequentially with 4-(benzyloxy)pyridin-2(1H)-one (448 mg, 2.23 mmol), 8-hydroxyquinoline (44 mg, 0.305 mmol), CuI (58 mg, 0.305 mmol) and K2CO3 (308 mg, 2.23 mmol). After stirring overnight at 130° C., the mixture was allowed to cool to room temperature and a mixture of MeOH and NH4OH (10:1, 10 mL) was added. After stirring for 15 min, the mixture was diluted with CH2Cl2, washed with brine, dried over Na2SO4, filtered and concentrated to dryness. Purification by flash column chromatography (40 g ISCO column eluting with a 1:1 ethylacetate/hexanes and a methanol/ammonia mixture (10:1); gradient 100% 1:1 ethylacetate/hexanes to 90% 1:1 ethylacetate/hexanes/10% methanol/ammonia mixture (10:1) over 30 min at 25 mL/min) provided the title compound (340 mg, 33%) as a yellow solid; 1H NMR (500 MHz, CDCl3) δ 7.50-7.36 (m, 8H), 7.13 (d, J=7.8, Hz, 1H), 6.09 (d, J=2.6 Hz, 1H), 6.03 (dd, J=7.5, 2.7 Hz, 1H), 5.05 (s, 2H), 4.65 (br s, 2H), 3.73 (br s, 2H), 3.66 (s, 3H), 2.77 (br s, 2H), 1.51 (s, 9H).

Provenance & Evidence