Stoffwechselprodukte von Mikroorganismen. 190. Mitteilung. Über das 4-Oxo-homotyrosin,ein Abbauprodukt des Echinocandins B

D , L -4-Oxo-homotyrosine was synthesized by the acetylaminomalonic ester pathway. The optical resolution was carried out by means of the enzyme acylase I. The L -configuration of the enzymatically produced amino acid was confirmed by degradation to L -aspartic acid. 4-Oxo-homotyrosine obtained by degradation of the polypeptide antibiotic echinocandine B has D -configuration, but his optical purity is low. A hypothetical explanation for its formation from the (2 S, 3 S, 4 S)-3,4-dihydroxyhomotyrosine residue of echinocandine B is proposed.