Bicarbonate Ion → (2R)-2-Phenylcarbonyloxypropyl(2S)-2-(tert-Butoxycarbonyl)amino-3-(3,4-dihydroxyphenyl)propanoate

Participants

Reaction Conditions

Reaction Steps

Boc-Dopa TBA salt 3 (50 g, 93 mmol), bicarbonate-washed (1R)-2-chloroisopropyl benzoate 5 (20 g, 100 mmol), and N-methylpyrrolidinone (NMP) (100 mL) were added to a 250 mL round bottom flask. The mixture was stirred under a nitrogen atmosphere and heated in an oil bath at 100° C. After ca. 72 hrs the reaction was cooled to room temperature, diluted with tert-butyl methylether (MTBE) (1 L), and washed twice with deionized water (2 L, then 1 L). The organic phase was separated, dried over anhydrous sodium sulfate (Na2SO4), filtered, and concentrated under reduced pressure to provide 35 g (76 mmol) of (2R)-2-phenylcarbonyloxypropyl(2S)-3-(3,4-dihydroxyphenyl)-2-[(tert-butoxy)carbonylamino]propanoate 6 as a tan, viscous oil.

Provenance & Evidence