内吸性杀菌剂三唑醇(酮)立体异构体的研究(Ⅱ)

Studies on Steromers of Triadimenol(Ⅱ)

确定了拆分三唑醇A、B两非对称异构体所形成的非对映中间体的结构,并得到100%光学纯的三唑醇右旋A体。经X-射线法等确定其绝对构型为(+)1R,2s,由Jones氧化反应得到100%光学纯的三唑酮右旋体,利用格氏氢转移反应对右旋三唑酮进行不对称还原得三唑醇的不同光学异构体。对小麦叶锈病的生物活性测定表明三唑醇中(-)-A-1S,2R的生物活性最高;三唑酮中,左右旋体的活性相当。

The two diastereomers(designated as Aand B)of Triadimenol were separated and the enantiomers of the active triadimenol Awere further resolved.The absolute configuration of(+)-triadimenol Awas determined both by Horeau method and X-ray diffraction method.Its oxidation to the corresponding(+)-triadimefon was successfully carried out for the first time by Jones'oxidation.The asymmetric reduction of(+)triadimefon was carried out by using an hydrogen transfer mechanism of Grignard reaction to obtain different optical isomers of triadimenol.The preliminary bioassay on mixed spores of wheat rust indicated that among the four optical isomers of triadimenol,(-)-A-lS,2Renantiomer has the highest bioactivity,whereas both levo-and dextro-isomers of triadimefon do not differ much in their bioactivities.