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51.
采用后合成修饰(PSM)技术将水杨醛锚装到UMCM-1-NH2上, 得到席夫碱功能化的多孔金属-有机骨架化合物UMCM-1-NH-Sal, 在该化合物孔道内的席夫碱N、 O原子上螯合铜离子得到UMCM-1-NH-Sal-Cu催化剂, 并用核磁共振氢谱(1H NMR)、 X 射线衍射(PXRD)、 热重分析(TG)、 N2 吸附-脱附等手段对催化剂进行了表征, 将其用于催化有机胺和环氧化物的开环反应制备β-氨基醇, 结果表明该催化剂具有良好的催化效果. 相似文献
52.
Xiaoyu LiuXiaozhen Jiao Qian WuChengsen Tian Renze LiPing Xie 《Tetrahedron letters》2012,53(29):3805-3807
A practical synthesis of Entecavir (1) has been accomplished in 10 steps with 21% overall yield. The key steps to construct the five-membered carbocyclic framework 2 are a ring-closing metathesis and a diethyl-aluminum 2,2,6,6-tetramethyl piperidide (DA-TMS) mediated epoxide isomerization. Furthermore, the guanine was introduced by modified Mitsunobu reaction. 相似文献
53.
1,1,3,3-四(全氟己基乙基)二锡氧烷二聚体在环氧化合物开环反应中的催化作用 总被引:2,自引:0,他引:2
采用氟碳-有机溶剂两相催化体系,考察了1,1,3,3-四(全氟己基乙基)二锡氧烷二聚体(1)在环氧化合物开环反应中的催化作用.结果表明,催化剂(1)在氟碳-有机溶剂两相体系中使环氧苯乙烯和甲醇的开环反应产率高达95%,13CNMR谱表明,开环反应的区域选择性为100%.在氟碳-有机溶剂两相催化体系中以一锅法制备了3-苯基丙酸2-甲氧基-2-苯乙醇酯,收率高,方法简便,催化剂几乎可以定量回收循环使用. 相似文献
54.
Epoxides and aziridines are cleaved efficiently and regioselectively in the presence of zirconyl nitrate at room temperature to afford the corresponding β-nitrato-alcohols and -sulfonamides, respectively, in high yields. 相似文献
55.
Habib Firouzabadi Nasser Iranpoor Abbas Ali Jafari Somayeh Makarem 《Journal of molecular catalysis. A, Chemical》2006,250(1-2):237-242
AlPW12O40 as a recyclable Lewis acid and stable solid compound was introduced for efficient ring opening of different epoxides with thiols, acetic acid, and primary, secondary, and tertiary alcohols. These processes were carried out at room temperature with high regio- and stereoselectivity. 相似文献
56.
57.
This paper describes a new synthetic route towards hydroxylated pyrrolidines and azepane derivatives starting from chiral epoxyamides. The alternate transformations on a ribose derivative α,β-epoxyamide permit the construction of five or seven member rings leading to different precursors of homoiminosugars. 相似文献
58.
The deoxygenation of styrene oxide with dichlorocarbene is studied by a combination of isotope effects and theoretical calculations. A normal 13C isotope effect of 1.016 is observed for the α-carbon of the styrene oxide but a surprising inverse isotope effect of 0.995 is observed at the β-carbon. This is indicative of a highly asynchronous process in which the Cα-O bond is broken without any progress in the breakage of Cβ-O bond. Theoretical calculations support this interpretation. This coarctate reaction is formally concerted as it avoids involving a high-energy intermediate, but it appears uninfluenced by transition state aromaticity. 相似文献
59.
Olivine-type Co2SiO4 ultrafine particles were synthesized by a sol-gel method using propylene oxide as a gelation agent. Owing to the high homogeneity
of the intermediate gel precursor, the usage of this epoxide method results in a substantial reduction of calcination temperature
and time as compared with the solid-state route, and a great reduction of calcination time as compared with other wet-chemistry
routes. This high homogeneity is obtained by the usage of an appropriate amount of HCl, as a catalyst that matches the rate
of hydrolysis of TEOS and the metal ions, allowing the formation of Si–O–Co bonds. 相似文献
60.
Rapid and efficient ring opening of epoxides catalyzed by a new electron deficient tin(IV) porphyrin
The new electron deficient tin(IV) tetraphenylporphyrinato trifluoromethanesulfonate, [SnIV(tpp)(OTf)2], was used as an efficient catalyst for the alcoholysis, hydrolysis and acetolysis of epoxides. Conversion of epoxides to thiiranes and acetonides were also performed efficiently in the presence of this catalyst. 相似文献