1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → (E)-3-(2,2-Dimethyl-3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazin-7-yl)-N-methyl-N-(3-methylbenzofuran-2-ylmethyl)acrylamide hydrogen chloride

Participants

Reaction Steps

To a solution of methyl-(3-methyl-benzofuran-2-ylmethyl)-amine (88 mg, 0.5 mmol) in DMF (5 mL) were added in sequential order 3-(2,2-dimethyl-3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazin-7-yl)acrylic acid hydrochloride (107 mg, 0.46 mmol), 1-hydroxybenzotriazole (68 mg, 0.5 mmol), diisopropylethylamine (240 uL, 1.38 mmol), and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (100 mg, 0.5 mmol). The mixture was stirred at room temperature overnight, cooled in an ice bath and water added with rapid stirring. The product was extracted with ethyl acetate (3×10 mL), dried with sodium sulfate, filtered and concentrated. The free base was re-solvated in methylene chloride (5 mL) and a solution of 4M HCl in dioxane (1 mL) was added to precipitate the hydrogen chloride salt as a pale yellow solid (84 mg, 43%): 1H NMR (400 MHz, DMSO-d6) δ 8.94 (1s, 1H), 8.01-8.06 (m, 2H), 7.47-7.58 (m, 3H), 7.16-7.25 (m, 3H), 4.73-4.94 (rotamers, 2s, 2H), 3.42 (s, 2H), 3.04 (s, 3H), 2.42 (s, 3H), 1.34 (s, 6H); MS (ESI) m/e 392 (C23H25N3O3+H)+.

Provenance & Evidence