| 摘要 |
NEW MATERIAL:A compound of formulaI R is 1-4C alkyl; A is divalent group of formula II, III (R<1>, R<2> are H, 1-8C alkyl, which may be substituted or incorporate to form methylene) . USE:Antitumor agent, farm chemicals. PREPARATION:For example, 20-demethoxy-20-hydroxymaytansinoids of formula IV is used as a raw material and the benzene ring in the conventional maytansinoids is oxidized to give a quinone compound (maytanquinoids). Namely, a compound of formula IV is dissolved in methanol, combined with a buffer solution of potassium dihydrogen phosphate and oxidized with a saturated Fremy's solution. The reaction mixture is extracted with a solvent such as chloroform, the extract is concentrated to dryness and the residue is purified by means of column chromatography to give the compound of formulaI. |
