Diphenyl chlorophosphate → HCID 57269025, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of allyl (4R)-2-diazo-4-[(2R,3S)-3-{(1R)-1-hydroxyethyl}-4-oxoazetidin-2-yl]-3-oxopentanoate (1.41 g) in ethyl acetate (14 ml) was added rhodium(II) octanoate (19 mg) under refluxing in a stream of nitrogen. The mixture was refluxed for 30 minutes and then evaporated in vacuo to give a residue. The residue was dissolved in acetonitrile (15 ml) and cooled at 0-5° C. under an atmosphere of nitrogen. To the solution were added diphenyl phosphorochloridate (1.09 ml) and N,N-diisopropyl-N-ethylamine (0.96 ml) successively and the mixture was stirred at the same condition overnight. On the other hand, to a solution of (2S,4S)-4-acetylthio-1-allyloxycarbonyl-2-(imidazo[1,2-b]-pyrazol-1-yl) methylpyrrolidine (2.33 g) in a mixture of tetrahydrofuran (20 ml) and methanol (20 ml) was added 28% sodium methoxide in methanol solution (1.41 ml) under ice-cooling and the mixture was stirred at the same temperature for 15 minutes. To the reaction mixture was added acetic acid (0.42 ml) and the mixture was evaporated in vacuo. The resulting residue was dissolved in ethyl acetate (50 ml). The solution was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate and evaporated in vacuo to give a residue. To the mixture obtained above were added a solution of this residue in acetonitrile (10 ml) and N,N-diisopropyl-N-ethylamine (1.25 ml) successively under ice-cooling and the mixture was stirred at the same temperature for 2 hours. To a reaction mixture were added ethyl acetate (100 ml) and water (50 ml) with stirring and separated. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate and evaporated in vacuo. The resulting residue was chromatographed on silica gel (100 g) eluting with a mixture of dichloromethane and acetone (2:1, V/V). The fractions containing the desired compound were collected and evaporated in vacuo to give allyl (4R,5S,6S)-3-[(2S,4S) -1-allyloxycarbonyl-2-(imidazo[1,2-b]pyrazol-1-yl) methylpyrrolidin-4-yl]thio-6-[(1R)-1-hydroxyethyl]-4-methyl-7-oxo-1-azabicyclo [3.2.0]hept-2-ene-2-carboxylate (1.66 g).

Provenance & Evidence