High‐performance liquid chromatography of 2,4‐disubstituted‐5(4H)‐oxazolones, anhydrides and other activated forms of N‐acyl‐ and N‐alkoxycarbonylamino acids

Publisher Website
Google Scholar
Abstract
Normal phase high-performance liquid chromatography has been achieved of the common activated forms of valine on a LiChrosorb-CN or a .mu.Porasil (underivatized silica) column using hexane containing 1.5 or 5% tert.-butanol as solvent. Compounds examined include the 2-alkoxy-5(4H)-oxazolones and symmetrical and mixed anhydrides of N-tert.-butoxycarbonyl-, N-benzyloxcarbonyl-, N-9-fluorenylmethoxycarbonylvaline, the chloride of the latter, a p-nitrophenyl ester, 2-methyl-4-isopropyl-5(4H)-oxazolone, valine-N-carboxyanhydride,and the N- and O-ethoxycarbonyl adducts of 1-hydroxybenzotriazole. The 5(4H)-oxazolones from N-tert-butoxycarbonylvaline and N-benzyloxycarbonylglycylvaline decomposed during chromatography on the .mu.Porasil but not the LiChrosorb-CN column. The method allows direct monitoring of reactions involving generation or consumption of activated forms of amino acids.

This publication has 22 references indexed in Scilit: