Hikaru Nakamura, Hiroyuki Suda, T. Takita
1976
Citations
0
Influential Citations
35
Citations
Journal
The Journal of antibiotics
Abstract
Sir: As reported in the preceding paper," 3amino-2-hydroxy-4-phenylbutanoic acid is a component in bestatin, an inhibitor of aminopeptidase B and leucine aminopeptidase. The absolute determination of its stereochemistry is possible by X-ray crystallographic analysis of a suitable derivative. Therefore, the hydrobromide of its methyl ester was crystallized and subjected to X-ray analysis. The results indicate a (2S, 3R)-configuration and confirmed that an experimental rule for the determination of configuration of a-amino-13-hydroxy acids developed by SHIBA et al."' can be applied to this (3-amino-a-hydroxy acid. A methanol solution (11.5 mg of 3-amino2-hydroxy-4-phenylbutanoic acid in 5 ml) of material isolated from the acid hydrolysate of bestatin, and 0.2 ml of hydrobromic acid (d=1.48) was kept at room temperature for a week. After evaporation of the solvent, the methyl ester hydrobromide was crystallized from methanol-benzene, m.p. 172-173°C, VKBr 1740 cm-'. The crystals are thin, colorless, transparent plates. A crystal with approximate dimensions 0.55 x 0.4 0.03 mm was used for the X-ray diffraction study. The diffraction data were collected with a Philips PW 1100 diffractometer equipped with a graphite monochromator (Cuka radiation). The crystal data are given in Table 1.