Synthesis of Four Stereoisomers of 1,4-Thiazane-3-carboxylic Acid 1-Oxide<i>via</i>the Asymmetric Transformation (combined isomerization-preferential crystallization) of 1,4-Thiazane-3-carboxylic Acid
4-thiazane-3-carboxylic acid 1-oxide (TCA SO), (S)-1,4thiazane-3-carboxylic acid [(S)-TCA], which is one of the precursors, was prepared by the asymmetrictransformation (combined isomerization-preferential crystallization) of (RS)-TCA. This asymmetrictransformation was used (2R, 3R)-tartaric acid [(R)-TA] as a resolving agent and salicylaldehyde as the epimerization catalyst in propanoic acid at 110 degrees