2 The Absolute Configuration of Echinulin
Details
Echinulin was first isolated by Quilico's group, and its structure was established by same group, except for the configuration of optical active center of tryptophan moiety. Because this group is quite easy racemize during the chemical reactions. To decide the configuration of echinulin, many physical or chemical experiments (ex. ORD, NMR., Biosynthesis, TLC. etc.) were attempted. As shown in table 2 and 3, we suceeded to determine the configuration of echinulin by ozonolysis in HCOOH-H_2O, and followed by decomposition of ozonide by H_2O_2 and acid hydrolysis (Fig.3). Amino acid analyser and microbioassay using the Leconostoc mesenteroides P-60. showed th 94% of the aspartic acid was L-form. The obtaining of the L-aspartic acid indicates the absolute configuration of echinulin were determined as shown in structure II. This result coincide with the above physical or chemical data.
