Toluene → (1R,5S)-1-Amino-7-fluoro-4-oxo-3-[(1R)-1-phenylethyl]-3-azabicyclo[3.3.0]octane

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Reaction Steps

Toluene (10 mL) and triethylamine (565 μL, 4.05 mmol) were added to (1R,5R)-7-fluoro-4-oxo-3-[(1R)-1-phenylethyl]-3-azabicyclo[3.3.0]octan-1-ylcarboxylic acid (590 mg, 2.03 mmol). Then, diphenylphosphoryl azide (567 μL) was added, and the mixture was stirred at room temperature for 30 minutes. Thereafter, the reaction solution was heated to reflux for one hour and blended with a mixture of ethyl acetate-saturated sodium bicarbonate water. The organic layer was dried over magnesium sulfate and filtered. Then, the solvent was evaporated under reduced pressure. The residue was dissolved in dioxane (10 mL). 6N hydrochloric acid (10 mL) was added, and the mixture was heated with stirring at 70° C. for two hours. After washing with ether, the aqueous layer was made basic with a 10 M sodium hydroxide solution, followed by extraction with toluene five times. The extract was dried over magnesium sulfate and filtered, and then the solvent was evaporated under reduced pressure to give 476 mg (90%) of the title compound as a colorless oil. The product was used for the next step without purification.

Provenance & Evidence