synthesized from betulinic acid by its oxidation to 30-oxobetulinic acid followed by the Wittig reaction. Cytotoxicity of all compounds was tested in vitro in eight cancer cell lines and two noncancer fibroblasts. Almost all dienes were more cytotoxic than betulinic acid. Compounds 4.22, 4.30, 4.33, 4.39 had IC50 below 5 μmol/L; 4.22 and 4.39 were selected for studies of the mechanism of action. Cell cycle
通过将桦木酸氧化为 30-氧代桦木酸,然后进行 Wittig 反应,合成了一组新的取代二烯。在八种癌细胞系和两种非癌成纤维细胞中体外测试了所有化合物的细胞毒性。几乎所有的二烯都比桦木酸更具细胞毒性。化合物4.22、4.30、4.33、4.39的IC 50低于5 μmol / L ;选择4.22和4.39进行作用机制研究。细胞周期分析显示在 5 × IC 50时凋亡细胞数量增加浓度,其中可以预期导致细胞死亡的不可逆变化的激活。既4.22和4.39导致细胞在用DNA / RNA合成的部分抑制的G0 / G1期的累积为1×IC 50,并在5几乎完全抑制×IC 50。有趣的是,化合物4.39 在 5 × IC 50导致细胞在 S 期积累。较高浓度的受试药物可能比较低浓度抑制更多的脱靶。破坏细胞代谢的机制可以诱导细胞在 S 期的积累。化合物4.22和4.39 均在癌细胞中引发选择性凋亡通过内在途径,
PREPARATION OF ALLYL VINYL ETHERS BY WITTIG REACTION OF ALLYL FORMATES
作者:Minoru Suda
DOI:10.1246/cl.1981.967
日期:1981.7.5
Substituted allyl vinyl ethers are obtainable by the reaction of allyl formates with Wittigreagents. Reactivity of some of the produced allyl vinyl ethers was also examined.
Kinetics of proton transfer from phosphonium ions to electrogenerated bases: polar, steric and structural influences on kinetic acidity and basicity
作者:Ana-Paula Bettencourt、Ana Maria Freitas、M. Irene Montenegro、Merete Folmer Nielsen、James H. P. Utley
DOI:10.1039/a708086g
日期:——
linear sweep voltammetry (LSV) have been used to measure rates of protontransfer in DMSO solution between different types of electrogeneratedbase (EGB) and a series of phosphonium ions of relevance to ylide formation for synthetic reactions. Although the electrochemical methods are convenient for the measurement of rates of protontransfer in these systems a major conclusion of the study is that considerable
导数循环伏安法(DCV)和线性扫描伏安法(LSV)已用于测量DMSO溶液中质子在不同类型的电生成碱(EGB)与一系列与叶立德形成有关的合成反应之间的transfer离子转移速率。尽管电化学方法可方便地测量这些系统中的质子转移速率,但这项研究的主要结论是,在应用这些方法并从结果中得出一般结论时必须格外小心。尤其是将动酸度与热力学p K进行比较DMSO中的值表明,一系列Br离子不满足单个布朗斯台德关系。动酸度受到以下因素的严重影响:EGB是碳还是氮碱;一些the离子的烯醇化倾向;和空间因素。在酸性亚甲基上的其他电子需求量度(13 C和1 H化学位移,还原电位)与p K(DMSO)值一致。动力学结果证实,对于不可烯醇化的salts盐,Ph 3 P +基团比Bu 3 P +更具活化性。
Short and efficient preparation of trifluoromethyl vinyl sulphides
S-Alkyl trifluorothioacetate 2 reacts with stabilized and non-stabilized phosphoranes 1 to afford a new and general route to a wide range of trifluoromethyl vinyl sulphides 3. Until now, no general methods allowed the preparation of these interesting compounds.