共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
3.
手性相转移催化烷基化研究 总被引:1,自引:0,他引:1
手性相转移催化烷基化研究曾和平(华南师范大学化学系,广州510631)在合成具有重要生理活性天然产物时,立体择选烷基化反应是合成具有特定立体结构的光活性产物的重要步骤之一 ̄[1]。1981年Matsuo报道了2-乙氧羰基环戊酮在氢化钠作用下,以DMF... 相似文献
4.
5.
在SmI3作用下和中性室温的条件下, 环戊酮能与醛缩合, 得到几乎定量产率的α, α'-二亚苄基环戊酮; 但对环己酮, 产率仅在20%左右。 相似文献
6.
7.
8.
9.
不动杆菌静息细胞催化拆分外消旋环戊酮醇乙酸酯反应条件的优化 总被引:4,自引:0,他引:4
考察了反应条件对不动杆菌Acinetobactersp.YQ231催化外消旋环戊酮醇乙酸酯对映选择性水解的反应速度和对映选择性的影响.确定的最佳酶反应条件为pH8.0,温度50℃.不同乳化剂对对映选择性的影响不同,以壬基酚聚氧乙烯醚的效果最好,当其加入量为15g/L时,反应的对映选择性最高.产物环戊酮醇对酶活性有显著的抑制作用.细胞中的酯酶优先水解(R)-环戊酮醇乙酸酯,生成(R)-环戊酮醇,在底物浓度为250mmol/L时,对映体比率(E值)可达50. 相似文献
10.
以TiO2为载体负载双金属活性组分Ni-Co,采用浸渍法制备催化剂,用于糠醛催化加氢生成环戊酮和环戊醇的反应,并探讨了Ni-Co负载量、反应时间、反应温度、反应压力对其他产物的影响。通过XRD、BET、H2-TPR、SEM等表征方法对催化剂的构成及反应机理进行了讨论。结果表明,分别以一定比例负载金属活性组分制备的Ni-Co/TiO2和Co/TiO2催化剂,在最佳反应条件下环戊酮和环戊醇的生成率达到最高值,分别为53.4%和17.1%。 相似文献
11.
Cyclopentylidene ketals of 3-(D-erythro and L-threo-glycerol-1-yl) of l-phenyl-2-pyrazoline-4,5-dione-4-phenylhydrazone and 1 -phenylflavazole were prepared. The location of the ketal ring on the glycerolyl residues was determined by NMR spectral analyses. 相似文献
12.
Dmitry S. Yufit Judith A. K. Howard 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(3):o104-o106
Crystals of cyclopentanone, C5H8O, and cyclobutanone, C4H6O, have been grown in situ on a diffractometer. The two compounds are isostructural and contain two crystallographically independent molecules. Molecules sitting across twofold axes form antiparallel dipole–dipole dimers, while other molecules in general positions are linked together into ribbons by pairs of C—H...O interactions. 相似文献
13.
Jean M. J. Tronchet Guido Zosimo-Landolfo Fabienne Villedon-Denaide Mirna Balkadjian Daniel Cabrini Françoise Barbalat-Rey 《Journal of carbohydrate chemistry》2013,32(6):823-835
ABSTRACT Cyclopentylidene ketals, moderately more acid-labile than their isopropylidene analogs, offer an alternative to the latter blocking groups. They have been shown to resist a large variety of reaction conditions commonly encountered in carbohydrate chemistry. 相似文献
14.
15.
Among various categories of potential biofuel molecules, ketones are of significant interest. Cyclopentanone is a cyclic ketone that can be produced from biomass, and its combustion is still unknown. Moreover, its cyclic configuration makes it an interesting feedstock for the further production of high‐density fuels such as bi(cyclopentane). This study reports the first computational kinetic investigation of the unimolecular decomposition pathways of cyclopentanone by using the compound G3B3 method. The rate constants were calculated using Rice–Ramsperger–Kassel–Marcus theory in the temperature range of 800–2000 K. The results presented here can be used in a future kinetic combustion mechanism. 相似文献
16.
Catalytic condensation of cyclopentanone with arylmethylene(6-quinolyl)amines gave previously unknown 8-aryl-10,11-dihydro-9H-cyclopenta[a]-4,7-phenanthrolines. 相似文献
17.
Zhao-hui Li Ye-peng Yu Xuan Lin Jun Chen Hang Zhang Yan-bo Li Huan-huan Wang Qing-hui Meng Rui-rui Sun Xiao-bin Shan Fu-yi Liu Liu-si Sheng 《化学物理学报(中文版)》2018,31(5):619-625
The dissociative photoionization of cyclopentanone was investigated by means of a reflectron time-of-flight mass spectrometer (RTOF-MS) with tunable vacuum ultraviolet synchrotron radiation in the photon energy range of 9.0-15.5 eV. The photoionization efficiency (PIE) curves for molecular ion and fragment ions were measured. The ionization energy of cyclopentanone was determined to be 9.23\begin{document}$\pm$\end{document} 0.03 eV. Fragment ions from the dissociative photoionization of cyclopentanone were identified as C\begin{document}$_5$\end{document} H\begin{document}$_7$\end{document} O\begin{document}$^+$\end{document} , C\begin{document}$_4$\end{document} H\begin{document}$_5$\end{document} O\begin{document}$^+$\end{document} , C\begin{document}$_4$\end{document} H\begin{document}$_8^+$\end{document} /C\begin{document}$_3$\end{document} H\begin{document}$_4$\end{document} O\begin{document}$^+$\end{document} , C\begin{document}$_3$\end{document} H\begin{document}$_3$\end{document} O\begin{document}$^+$\end{document} , C\begin{document}$_4$\end{document} H\begin{document}$_6^+$\end{document} , C\begin{document}$_2$\end{document} H\begin{document}$_4$\end{document} O\begin{document}$^+$\end{document} , C\begin{document}$_3$\end{document} H\begin{document}$_6^+$\end{document} , C\begin{document}$_3$\end{document} H\begin{document}$_5^+$\end{document} , C\begin{document}$_3$\end{document} H\begin{document}$_4^+$\end{document} , C\begin{document}$_3$\end{document} H\begin{document}$_3^+$\end{document} , C\begin{document}$_2$\end{document} H\begin{document}$_5^+$\end{document} and C\begin{document}$_2$\end{document} H\begin{document}$_4^+$\end{document} . With the aid of the ab initio calculations at the \begin{document}$\omega$\end{document} B97X-D/6-31+G(d, p) level of theory, the dissociative mechanisms of C\begin{document}$_5$\end{document} H\begin{document}$_8$\end{document} O\begin{document}$^+$\end{document} are proposed. Ring opening and hydrogen migrations are the predominant processes in most of the fragmentation pathways of cyclopentanone. 相似文献
18.
O. V. Bykhovskaya I. M. Aladzheva I. V. Leontieva P. V. Petrovskii T. A. Mastryukova M. I. Kabachnii 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Direction of alkylation of phosphoranes (I) depends on the nature of the substituent Y and the alkylating agent. Unsubstituted phosphorane reacts with CH3J yielding only the product of C-methylation (II), whereas the reaction with Me2SO4 proceeds at both ends of the OPC-triad, preferably yielding the O-alkylation product (IIIa, 80%). 相似文献
19.
Meier MS Bergosh RG Gallagher ME Spielmann HP Wang Z 《The Journal of organic chemistry》2002,67(17):5946-5952
The fulleride dianions C(60)(2-) and C(70)(2-) were generated by deprotonation of the corresponding hydrogenated fullerenes, 1,2-C(60)H(2) and 1,2-C(70)H(2). These anions were prepared in the presence of a variety of alkylating agents, and mono- or dialkylated products were obtained. Alkylation was not successful with sulfonate ester alkylating agents. Deprotonation of monoalkylated compounds, followed by second alkylation with a different alkylating agent, produced heterodialkylated compounds. The monoalkyated material was invariably the 1,2-isomers, while the dialkylated materials were generally 1,4-isomers, although some 1,2-isomer was observed in the C(70) context. The major product from alkylation of C(70)(2-) was the 7,23-isomer 13a, a structure where the alkylation took place near the equator of the fullerene cage, rather than at the more strained carbons near the poles. 相似文献
20.
2-Alkylamino-4-ethylthiazoles were obtained by the alkylation of 2-amino-4-ethylthiazole with secondary alcohols, while 2-amino-4-ethyl-5-tert-butylthiazole was obtained by the reaction of the thiazole with tert-butyl alcohol. 相似文献