Synthesis of 2-alkylcysteine via phase transfer catalysis

摘要

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. In one embodiment, the present invention provides methods of preparing 2-alkylcysteine derivatives. In another embodiment, the method comprises forming a 2-alkylcysteine derivative from a cysteine derivative in the presence of a phase transfer catalyst. In particular, the present invention provides methods for preparing 2-methylcysteine derivatives.;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 one aspect, an aryl nitrile or imidate is condensed with cysteine or a 2-alkyl cysteine. The present invention also relates to the preparation of 4,5-dihydro-2-(2,4-dihydroxyphenyl)-4-alkyl-thiazole-4-carboxylic acids, such as 4,5-dihydro-2-(2,4-dihydroxyphenyl)-4-methyl-thiazole-4-carboxylic acid.