土槿皮乙酸的绝对构型

报导了用圆二色散激子手性法测下土槿皮乙酸的绝对构型, 结果表明具有3s, 4s,10R及11R的绝对构型.     

番荔枝皂素(4S,5S)和(4S,5R)-Muricatacin的合成及Annonacin四氢呋喃段绝对构型的确证

本文以L-谷氨酸为原料合成了(1S,5S)和(4S,5R)-Muricatacin,并以该两化合物的NMR和[a]~D数据确证了Annonacin中四氢呋喃段的四个手性中心为(15R,16R,19R,20R).     

神农架地区五味子科植物成分的研究 III: 五味子酯G,H和I的分离与结构研究

本文继续报道从湖北房县中坝采集的一种南五味子(Kadsura sp.种名待定)根中分得的另外三个木脂素类新化合物: 五味子酯(schisantherin)G, H, I和六个已知物:schizandronic acid, isoschizandrolie acid, kadsurarin, veraguensin, β-谷甾醇和硬脂酸的分离, 鉴定与结构研究. 同时报道在结构研究中获得的八个衍生物的理化数据以及kadsurarin(1a)的绝对构型.     

海南新碱衍生物的化学

海南新碱及其异己烯基取代的海南新碱是通过分子间区域选择性环化反应获得。取代海南新碱在不同条件下的还原可得一系列4-甲基戊烯或4-甲基戊烷海南新碱衍生物, 用化学关联, 光谱分析和X-射线衍射确立了它们的立体化学。     

一种简易的光活性1，1′－联二萘酚合成方法

筛选出两种较好的1，1′－联二萘酚拆分剂L－TAC－TMEDA（收率75％，86％ ee）和L－PAC（酒石酸）－TMEDA（收率67％，71％ee)，同时以L－PAC（脯氨酸） 、TMEDA和CuCl的配合物PTCu为催化剂，在空气中催化剂量为1.5mol时，用氧化耦 合方法不对称合成了光活性联二萘酚，收率70％，35％ee，且回收的催化剂不需活 化，可直接重复使用。     

Enantio-differentiating hydrogenation of methyl acetoacetate over modified nickel catalysts: effects of nickel dispersion on the enantio-selectivity of catalysts

Enantio-differentiating hydrogenation of methyl acetoacetate was performed over the supported nickel catalysts modified by the solution of (R,R)-tartaric acid or (S)-malic acid and NaBr. The reduction temperature of supported nickel was the most important factor determining the enantio-selectivity of catalysts. The reduction temperature changed the nickel dispersion, by which the quantity and coverage of modifier adsorption were varied. The enantio-selectivity of modifiers both (R,R)-tartaric acid and (S) -malic acid were compared at various reduction temperatures. (R,R)-tartaric acid with two hydroxyl groups in a molecule showed an optimum coverage on the nickel surface that gave the maximum ee value. The maximum ee value was 72% at the reduction temperature of 973 K. In contrast, (S)-malic acid with one hydroxyl group in a molecule showed a monotonous decrease in ee and decreasing amounts of adsorbed modifier with increasing reduction temperatures.     

软珊瑚群柱虫中新的二萜化合物-群柱内酯萜的分离和结构测定

A new bicyclo[9.3.0]tetradecane diterpenoid (dolabellane) lactone named clavulactone (I) was isolated from soft coral qunzhuchong (Clavularia sp.). Its partial structure was determine by spectral anal. and hydrogenation reaction. X-ray anal. established the complete mol. structure of I and the relative configuration. Finally, according to the neg. Cotton effect of n畃* and CD band of a,b-unsatd. d-lactone at 252 nm, the absolute configuration was assigned.     

(一)-莪术二酮的全合成

(+)-莪术二酮系从中药温莪术中分到的抗癌活性成份. 本文研究了由(-)-香芹酮经12步反应合成(-)-莪术二酮的过程, 并以此结果证实了天然(+)-莪术二酮的绝对构型.