Pyridine → tert-Butyl 5-(2-tert-butoxy-2-oxoethyl)-3-(5-((4-carbamimidamidobenzoyl)oxy)-2-methylphenyl)-4,5-dihydro-1,2-oxazole-5-carboxylate

Participants

Reaction Steps

4-Carbamimidamidobenzoyl chloride hydrochloride (173 mg) was added to a mixture of tert-butyl 5-(2-tert-butoxy-2-oxoethyl)-3-(5-hydroxy-2-methylphenyl)-4,5-dihydro-1,2-oxazole-5-carboxylate (290 mg), pyridine (1 mL), and NMP (3 mL) at 50 C, and the obtained mixture was stirred at 50 C for 20 minutes. Further, 4-carbamimidamidobenzoyl chloride hydrochloride (173 mg) was added thereto, and the obtained mixture was stirred at 50 C for 20 minutes. Further, 4-carbamimidamidobenzoyl chloride hydrochloride (173 mg) was added thereto, and the obtained mixture was stirred at 50 C for 3 hours. Further, 4-carbamimidamidobenzoyl chloride hydrochloride (173 mg) was added thereto, and the obtained mixture was stirred overnight at 50 C. The reaction mixture was purified by silica gel column chromatography (NH, ethyl acetate/hexane, subsequently methanol/ethyl acetate) and then further fractionated by HPLC (C18, mobile phase: water/acetonitrile (system containing 0.1% TFA)). To the obtained fraction, a saturated aqueous solution of sodium bicarbonate was added, followed by extraction with ethyl acetate. The extract was dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain the title compound (210 mg).

Provenance & Evidence