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141.
The stereochemistry of carbonyl olefination reaction of cyanomethylene triphenylarsorane with ketones is reported. The thermodynamically stable E isomer of the products α, β unsaturated nitrile was formed predominantly. Under the experimental conditions we adopted, the reaction conditions had little effect on the E, Z ratio of the reaction products. However, the structure of the substrate showed profound effect. The results shown in Table 1 are similar to that of the reaction of carbomethoxymethylene triphenylarosorane reported in the previous paper. When methyl t-butyl ketone was used as the substrate and the reaction carried out in benzene solution, nearly pure E isomer was obtained. The reaction mechanism was proposed as shown in the previous paper. When Δ4-cholesten-3-one was used as the substrate, change of the solvents showed more prominent effect on the E, Z ratio of the reaction product. This paper also deals with the reaction of three electron-withdrawing group (CN, COOCH3, COCH3) substituted methyltriphenylarsonium salts with ketones in the presence of K2CO3, Na2CO3/benzo-15-crown-5, K2CO3/18-crown-6 or (C2H5)3N in CH3OH solution. The latter three gave satisfactory results (Table 2). The chromotographically pure products could be obtained from the crude products by passing through silica gel column. Its E, Z ratio is nearly the same as that of the crude product. This method seems to be a good one for preparing olefinic compounds in miligram scale. 相似文献
142.
苯甲酰基五氟丙酰基亚甲基三苯基胂的亚甲基上带有两个强吸电子基团.由甲醇-水溶液中获得的该化合物单晶属三斜晶系,空间群为PI;晶胞参数a=12.292A,b=13.457A,c=15.318A,α=90.562°,β=90.516°,γ=92.82°;Ζ=4.用四圆衍射仪收集X射线衍射强度数据,用重原子法进行结构测定,用块对角矩阵阻尼最小二乘法进行结构修正.对8393个独立的可观测衍射点,最后的R因子为0.061.叶立德碳原子具有sp~2杂化的平面构型.As-C(1)键长为1.888A,比As=C双键长得多,也比已报道的其它胂叶立德的相应键长为长,表明“ylene”型结构的贡献较小.强吸电子基团的存在有利于负电荷的离域化,导致化学稳定性的增加. 相似文献
143.
用pH电位法研究了1-乙酰胺基丙叉-1,1-二膦酸(S-186)和1-丙酰胺基乙叉-1,1-二膦酸(S-106)与碱土金属的螯合作用(30±O.1℃).当金属离子与配体的摩尔浓度比为10∶1、1∶1和1∶2时,在水溶液中形成了MHL、ML、ML_2和M_2L等几种类型的配合物.分别测定了它们的稳定常数,其中S-186配合物稍高于S-106,说明配合物稳定性与螯合剂的碱度有平行关系.值得注意的是,这两种螯合剂与Sr~(2 )形成的双核配合物的稳定性均较其它碱土金属离子的为高. 相似文献
144.
Reaction of perfluoropropylene (2a) with cyanomethylene- triphenylarsorane (1b) gave cyano-2, 3, 3, 3-tetrafluoropropionylmethylene-triphenylarsorane (4b), and with benzoylmethylene-(1c) and acetylmethylene-triphenylarsorane (1d) gave benzoyl-(3c) and acetyl-(trans-perfluoropropen-1-yl)- methylene-triphenylarsorane (3d), respectively 3c and 3d could be converted to benzoyl-(4c) and acetyl-2, 3, 3, 3-tetrafluoropropionyl -methylene triphenylarsorane (4d), respectively by refluxing with moist benzene. Reaction of carbomethoxymethylene- triphenylphosphorane (1e) with perfluoropropylene was similar to that of arsorane. However, benzoylmethylene-and acetylmethylene- triphenylphosphorane were unreactive towards perfluoropropylene. Reaction of carbomethoxymethylene-triphenylarsoraen (1a) with trifluorochloroethylene gave carbomethoxyfluoroacetylmenthylene- triphenylarsorane (4f) in low yield. when the residue was treated with methanol, difluorotriphenylarsorano and methyl- fluorochloroacetate (8) were obatined. The structures of the aforementioned products are ascertained by elemental analyses, IR, ^1H NMR, ^1^9F NMR and mass spectra. 相似文献
145.
几种新的4-酰基吡唑酮类螯合剂的合成 总被引:37,自引:1,他引:36
Eight new 1-phenyl-3-methyl-4-acyl-pyrazolones (1a-f, 2a, b) have been synthesized in good yield by reacting the corresponding acid halide with 1-phenyl-3-methyl-pyrazolone in dioxane in the presence of suspended Ca(OH)2 or Ba(OH)2, the products were identified by elemental analyses, IR, UV and 1H NMR spectra. Preliminary experiments indicate that all of their extraction efficiency for (UO2)2+ in chloroform-water are better than that of PMBP. The relative efficiency is found to be of the following order: 1b, 1d, 1f>1a, 1e>1c, 2a>2b>PMBP. 相似文献
146.
147.
研究了13β-乙基-3-甲氧基-甾-1,3,5(10),9(11)-四烯-17β-醇与间氯过氧苯甲酸的氧化反应, 得到了9β-羟基-11酮化合物和一个未知化合物9α-过氧甲氧基-11-酮化合物。推测了反应机理, 讨论了未知物的化学结构和构型。 相似文献
148.
149.
深入研究了C60与全氟酰基过氧化物的反应,通过变温EPR测试证实了此反应的 自由基加成机理.用色谱分析并结合产物的^19F NMR结构鉴定,首次发现由于加成 过程中发生的全氟烷基自由基的β—Scission,生成了新的氟烷基自由基,从而生 成了多种氟烷基化的C60.表面性能研究发现氟烷基化的C60具有优良的疏水、疏油 性.总之,利用C60与全氟酰基过氧化物的反应,成功地对C60进行了全氟烷基化修 饰. 相似文献
150.
介绍了“碳中心”手性有机硅化合物的合成,以及在烯丙基硅烷与醛的Hosomi-Sakurai反应和α-烯丙基硅碳负离子与醛的反应中的应用。提出并实践了两条提高对映选择性的途径。烯基硅醇的不对称环氧化反应扩展了Sharpless反应的适用范围,为合成光活性的具简单结构的环氧化合物提供了一条简易的途径。 相似文献