Studies on Optically Active Amino Acids. VIII. Studies on α-Alkyl-α-amino Acids. III. Determination of Absolute Configuration of Optically Active Isovaline.
The absolute configuration of (+)-isovaline ((+)-VIII) was correlated with D-(-)-quinic acid ((-)-XI) by leading to (+)-5-ethyl-5-methyl-2-pyrrolidinone ((+)-XXIX-A and B) from (+)-isovaline and D-(-)-quinic acid. It was recommended that (+)-isovaline should be shown by the formula IX or X, that is, S(+)-isovaline. The solvent effects on ORD curves of (+)-XXXI were also observed.
