56222-82-3 L-Threonine, N-((5-chloro-3,4-dihydro-8-hydroxy-3-methyl-1-oxo-1H-2-benzopyran-7-yl)carbonyl)-, (R)- N-((5-Chloro-8-hydroxy-3-methyl-1-oxo-7-isochromanyl)carbonyl)threonine