Acetonitrile → tert-butyl 3(S)-[1(R)ethoxycarbonyl-6-phthalimidohexyl]-amino-4-oxo-2,3,4,5-tetrahydro-1,5-benzoxazepine-5-acetate

Participants

Reaction Conditions

Reaction Steps

A mixture of tert-butyl 3(S)-amino-4-oxo-2,3,4,5-tetrahydro-1,5-benzoxazepine-5-acetate (2 g), ethyl 2-bromo-7-phthalimidoheptanoate (3.9 g), acetonitrile (100 ml) and triethylamine (0.9 g) is heated at 80° C. for 3 days. After evaporation of acetonitrile, water (150 ml) and ethyl acetate (200 ml) is added to the residue, and the mixture is agitated thoroughly. The ethyl acetate layer is dried over anhydrous magnesium sulfate and concentrated in vacuo. The oily residue is dissolved in a mixture of ethyl acetate (10 ml) and oxalic acid (2 g). The resulting solution is diluted with petroleum ether (200 ml) and agitated thoroughly. The supernatant layer is removed by decantation. To the precipitate are added water (150 ml), ethyl acetate (200 ml) and sodium bicarbonate with stirring. The ethyl acetate layer is separated, dried over anhydrous magnesium sulfate and concentrated in vacuo. The oily residue is chromatographed graphed on silica gel using hexane-ethyl acetate (2:1-1:1) as an eluent. Evaporation of the first fraction affords tert-butyl 3(S)-[1(R)ethoxycarbonyl-6-phthalimidohexyl]-amino-4-oxo-2,3,4,5-tetrahydro-1,5-benzoxazepine-5-acetate (0.65 g) as a colorless oil.

Provenance & Evidence