Boranes in Synthesis. 5. The Hydroboration of Enamines with Mono- and Dialkylboranes. Asymmetric Synthesis of .beta.-Amino Alcohols of Moderate Enantiomeric Purity from Aldehyde Enamines
摘要:
The hydroboration of both acyclic and cyclic aldehyde and ketone enamines with such representative mono- and dialkylboranes as thexylborane and dicyclohexylborane, followed by an oxidative workup, yields the corresponding beta-amino alcohols in good to excellent isolated yields. The hydroboration of ketone and aldehyde enamines with the asymmetric hydroboration reagents monoisopinocampheylborane ((d)IpcBH(2)) and diisopinocampheylborane ((d)Ipc(2)BH) was also investigated, (d)Ipc(2)BH is highly effective for the asymmetric hydroboration of acyclic aldehyde enamines, such as 1-(4-morpholino)-3-phenyl-1-propene and 1-(1-pyrrolidino)-1-octene. Oxidation of the intermediate trialkylborane furnishes the corresponding beta-amino alcohols in 50-86% ee. The stereogenic center of the carbinol carbon is consistently enriched in the R-enantiomer when (d)Ipc(2)BH prepared from (+)-alpha-pinene is used as the hydroboration reagent. The enantiomeric excesses of the beta-amino alcohols synthesized in this study were determined by HPLC using a chiral stationary phase. The absolute configurations of some of the beta-amino alcohols synthesized in this study were determined by chiral HPLC comparison with authentic beta-amino alcohols prepared from chiral epoxides of known absolute configuration.
Optimisation of the Anti-Trypanosoma brucei Activity of the Opioid Agonist U50488
作者:Victoria C. Smith、Laura A. T. Cleghorn、Andrew Woodland、Daniel Spinks、Irene Hallyburton、Iain T. Collie、N. Yi Mok、Suzanne Norval、Ruth Brenk、Alan H. Fairlamb、Julie A. Frearson、Kevin D. Read、Ian H. Gilbert、Paul G. Wyatt
DOI:10.1002/cmdc.201100278
日期:2011.10.4
Active Compounds (LOPAC) against cultured Trypanosoma brucei, the causative agent of African sleeping sickness, resulted in the identification of a number of compounds with selective antiproliferative activity over mammalian cells. These included (+)‐(1R,2R)‐U50488, a weak opioidagonist with an EC50 value of 59 nM as determined in our T. brucei in vitro assay reported previously. This paper describes
针对培养的布氏锥虫(非洲昏睡病的病原体)筛选 Sigma-Aldrich 药理活性化合物库 (LOPAC) ,鉴定出许多对哺乳动物细胞具有选择性抗增殖活性的化合物。其中包括 (+)-(1 R ,2 R )-U50488,这是一种弱阿片类激动剂,EC 50值为 59 n M,如我们之前报道的布氏锥虫体外试验所测定。本文描述了对 U50488 关键结构元素的修饰,以研究结构-活性关系 (SAR) 并优化该化合物的抗增殖活性和药代动力学特性。
Microwave-enhanced bismuth triflate-catalyzed epoxide opening with aliphatic amines
作者:Thierry Ollevier、Etienne Nadeau
DOI:10.1016/j.tetlet.2007.12.100
日期:2008.2
In the presence of a catalytic amount of Bi(OTf)3·4H2O and under microwave irradiation, neat mixtures of epoxides and amines afforded smoothly the corresponding 2-amino alcohols. A wide variety of aliphatic amines were reacted with cycloalkene oxide, styrene oxide, and stilbene oxide. The reaction proceeded rapidly and afforded the 2-amino alcohols in high up to quantitative yields. All products could
catalyzes the ring opening of epoxides by aryl, heterocyclic, or aliphatic amines under mild conditions. The reactions proceed at room temperature to afford the corresponding β-amino alcohols in excellent yields. In general, the aminolysis of cyclopentene oxide is faster than that of cyclohexene oxide in the presence of iridium trichloride as a catalyst. epoxides - iridium trichloride - amines - amino alcohols
Diamino benzo[b]thiophene derivatives as a novel class of active site directed thrombin inhibitors: 3. Enhancing activity by imposing conformational restriction in the C-4″ side chain1
作者:Jolie A. Bastian、Nickolay Chirgadze、Michael L. Denney、Donetta S. Gifford-Moore、Daniel J. Sall、Gerald F. Smith、James H. Wikel
DOI:10.1016/s0960-894x(98)00746-x
日期:1999.2
The preparation and biological evaluation of a series of benzo[b]thiophene diamine thrombin inhibitors possessing conformationally restricted C-4" linkers are reported. Compared to the parent compounds 1a/b, the unsaturated derivatives 3a/b exhibited a modest twofold increase in thrombin inhibitory activity, while the more lipophilic carbocyclic ring containing analogs 4a/b, affected an eightfold enhancement in potency. (C) 1999 Elsevier Science Ltd. All rights reserved.