| abstract |
Non-natural amino acids such as 2-alkylated amino acids allow for the synthesis of a wider variety of peptidal and non-peptidal pharmaceutically active agents. A method of preparing a 2-alkyl amino acid involves reacting cysteine (or a salt or an ester thereof) and an aryl carboxylic acid to form a thiazoline ring, stereospecifically alkylating the thiazoline ring, and hydrolyzing the thiazoline ring to obtain a 2-alkylcysteine (or related compound). The present invention also discloses a method of preparing a class of iron chelating agents related to desferrithiocin, all of which contain a thiazoline ring. In this method, an aryl nitrile or imidate is condensed with cysteine, a 2-alkyl cysteine, or a cysteine ester. |