菊酸构型的转化及消旋反式菊酸的光学拆分

CONFIGURATION CONVERSION OF CHRYSANTHEMIC ACID AND RESOLUTION OF THE DL_TRANS ENANTIOMER

混合消旋菊酸在含有ＡｌＢｒ３的二氧六环中可消旋化为ｄｌ－反式菊酸，产率ｗ为９６％．ｄｌ－反式菊酸用自制的（Ｒ）－（＋）－脱氢松香酸降解胺（即１－氨基－１，４ａ－二甲基－７－异丙基－１，２，３，４，４ａ，９，１０，１０ａ－八氢化菲）拆分可得ｄ－反式菊酸，二次拆分光学纯度为９５．４％～９９％ｅｅ．回收的富含ｌ－反式菊酸的副产物在ＡｌＢｒ３的二氧六环中加入微量的叔丁基过氧化氢（ｔ＿ＢｕＯＯＨ）可消旋化并可循环利用，产率质量分数ｗ为９１．５％．从混合菊酸出发经上述三个步骤处理可不断转化为高纯度ｄ－反式菊酸，总产率ｗ为６９％．

Mixed racemic chrysanthemic acid was converted into the dl_trans form by stirring it in a solution of AlBr 3 in dioxane, with yield w 96%. d_trans chrysanthemic acid was obtained by resoluting dl_trans enantiomer with a chiral amine (1_amino_1, 4a_dimethyl_7_isopropyl_1,2,3,4,4a,9,10,10a_octahydrophenanthrene) is a solution of 95% EtOH at 22 ℃. After twice resolution, the optical purity of product was 95.4%～99%ee. The by_product abundant in l_trans_isomer can be completely racemized in AlBr 3/dioxane solution with additional trace of t_BuOOH, with yield w 91.5%. By repeating the above racemization and resolution procedure, all the raw material, finally converted into d_trans chrysanthemic acid, with overall yield w 69%.