Triethylamine → (1S,6R)-1-Amino-7-oxo-8-[(1R)-1-phenylethyl]-8-azabicyclo[4.3.0]non-3-ene

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Reaction Steps

Triethylamine (1.61 mL, 11.5 mmol) and diphenylphosphoryl azide (1.62 mL, 7.52 mmol) were added to a solution of [(1S,6R)-7-oxo-8-[(1R)-1-phenylethyl]-8-azabicyclo[4.3.0]non-3-en-1-yl]carboxylic acid (1.65 g, 5.78 mmol) in toluene (28.9 mL) in a nitrogen atmosphere with stirring under ice-cooling, and the mixture was stirred at 100° C. for 30 minutes. The reaction solution was concentrated under reduced pressure, and triethylamine was azeotropically distilled with toluene (×3). 1,4-Dioxane (14.4 mL) and 4 mol/L hydrochloric acid (14.4 mL) were added to the resulting residue, and the mixture was stirred at 50° C. for six hours. The reaction solution was diluted with water (30.0 mL) and washed with ethyl acetate (50 mL×2). A 1 mol/L sodium hydroxide solution (55.0 mL) was added to the aqueous layer, followed by extraction with chloroform (100 mL×1, 80 mL×1). The organic layer was washed with brine (150 mL) and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure to give 1.24 g of the title compound as an amorphous.

Provenance & Evidence