| 摘要 |
The invention relates to two novel, optically active forms of 2-keto-3-methyl-4-hydroxyvaleric acid, of the formula <IMAGE> in which the C atom 4 has the (S) configuration. The C atom 3 can exist in the (R) and also the (S) configuration. The invention also relates to a microbiological process for the preparation of the compounds I. This process is characterized in that 4-hydroxyisoleucine (2S, 3R, 4S) (= L-4-hydroxyisoleucine), of the formula <IMAGE> is reacted with microorganisms which have L-amino acid oxidase (EC 1.4.3.2.) activity, or with an L-amino acid oxidase. The compounds I are interesting intermediates for the preparation of (5S)-3-hydroxy-4,5-dimethyl-2(5H)-furanone, which is optically active. |
