Abstract
dl-Neohydroxyaspergillic acid (I), the l-isomer of which has been isolated from Aspergillus flavus, was synthesized from DL-leucine anhydride. By treatment of 2-chloro-3, 6-diisobutylpyrazine 4-oxide (II) with acetic anhydride, an acetoxyl group was introduced into the isobutyl group. Deoxygenation of the N-oxide group at the 4-position of a 2-hydroxypyrazine 1, 4-dioxide derivative (XII), prepared by hydrolysis of a 2-chloro-pyrazine 1, 4-dioxide derivative (XI), was achieved using titanium (III) chloride to afford I.
