Tri-o-tolylphosphine → (E)-3-(2,2-Dimethyl-3-oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazin-7-yl)-N-methyl-N-(3-methylbenzofuran-2-ylmethyl)acrylamide

Participants

Reaction Steps

A solution of N-methyl-N-(3-methylbenzofuran-2-ylmethyl)acrylamide (0.231 g, 1.01 mmol) in propionitrile (4 mL) and DMF (0.8 mL) was deoxygenated with Ar for 20 min. The solution was treated with diisopropylethylamine (0.28 mL, 1.64 mmol) and 7-bromo-2,2-dimethyl-4H-pyrido[3,2-b][1,4]oxazin-3-one (0.200 g, 0.775 mmol). The solution was deoxygenated with Ar for 20 min. Pd(OAc)2 (0.017 g, 0.078 mmol) and P(o-tol)3 (0.047 g, 0.15 mmol) were then added and the solution was deoxygenated again with Ar for 10 min. The mixture was heated to reflux for 18 h, then allowed to cool. The mixture was diluted with H2O (100 mL). The resulting solids were collected by filtration and washed with Et2O (50 mL). Residual palladium was removed by silica gel plug (silica gel, 95:5, CH2Cl2/MeOH) the resulting solution concentrated to reveal a light orange solid. The solid was triturated with Et2O and dried to give the title compound (0.14 g, 46%) as a light pink solid and as a mixture of amide rotamers: 1H NMR (300 MHz, DMSO-d6) δ 11.41 (s, 1H), 8.20-8.19 (m, 1H), 7.97-7.93 (m, 1H), 7.57-7.48 (m, 3H), 7.28-7.23 (m, 3H), 5.00-4.78 (m, 2H), 3.17-2.92 (m, 3H), 2.62 (s, 3H), 1.44 (m, 6H); MS (ESI) m/e 406 (M+H)+.

Provenance & Evidence