Triethylamine → Diethyl Sulfate

Participants

Reaction Steps

Reaction Scheme A above begins with the triflate of a carboxyl-protected D-αhydroxycarboxylic acid derivative, e.g., lactic acid benzyl ester. By reacting this triflate with α-ethyl-γ-anilido-L-glutamate (prepared, for example, by reacting an amino-protected L-glutamic acid, such as Nα -Cbo-L-glutamic acid, with diethyl sulfate in triethylamine and dichloromethane at room temperature for about three days to give Nα -Cbo-α-ethyl-L-glutamate, forming the dicyclohexylamine salt of the thus-obtained glutamate by reaction with dicyclohexylamine in ethyl acetate at room temperature overnight, acidifying a suspension of the dicyclohexylamine salt and then reacting the isolated free acid with dicyclohexylcarbodiimide and aniline in dichloromethane, first in a dry ice/ice/acetone bath for one hour, and then at room temperature overnight), Nα -[1(L)-carbethoxy-3-carboxanilidopropyl]-L alanine benzyl ester is obtained.

Provenance & Evidence