Pairing heterocyclic cations with closo-dodecafluorododecaborate (2−)
摘要:
Eight binary salts that pair triazolium(1+), imidazolium(1+). pyrimidinium(1+), or purinium(1+) cations with the icosahedral closo-dodecafluorododecaborate(2-) anion (B12F122-) were synthesized using open-air benchtop metathesis reactions in water or acetonitrile. The scale of the reactions varied from just milligrams to nearly one gram of the K2B12F12 starting material. Other reaction conditions, the scope of the reaction, and the solubilities for the new salts are discussed. Five [heterocyclium](2)[B12F12] salts, which were obtained in yields ranging from 84% to 99%, displayed significantly higher densities than the corresponding previously reported analogous [heterocyclium](2)[B12H12] and [heterocyclium][CB11H12] salts. A ninth high-density salt consisted of B12F122- paired with a complex Ag-4(triazole)(8)(4+) cation. The structures of eight of the nine new compounds were determined by single-crystal X-ray diffraction analysis. The density of five [heterocyclium](2)[B12F12] salts was found to increase approximately linearly as the distance between the five-membered-ring heterocyclium(1+) cation centroids decreased. This work demonstrates additional flexibility for the rational design of ionic structures with predictable properties, which will ultimately permit the tailoring of ingredient-response behavior. Published by Elsevier B.V.
Welwitindolinone C synthetic studies. Construction of the welwitindolinone carbon skeleton via a transannular nitrone cycloaddition
摘要:
Described is the construction of the N-methylwelwitindolinone C core via an efficient strategy that employs a sequential rhodium carbenoid-mediated O-H insertion, Claisen rearrangement and transannular [3+2] nitrone cycloaddition. (C) 2010 Elsevier Ltd. All rights reserved.
Continuous flow solvent free organic synthesis involving solids (reactants/products) using a screw reactor
作者:Brijesh M. Sharma、Ranjit S. Atapalkar、Amol A. Kulkarni
DOI:10.1039/c9gc02447f
日期:——
nucleophilic substitutions, protection, acylations and coupling reactions using a mechanochemical approach at a controlled temperature using a single synthesis platform. Almost minimal solvents or solvent-free conditions are used, making it a very efficient and clean synthesis of various products. A jacketed screw reactor when operated at different temperatures (0 °C to 160 °C) and over a range of
Preparation and study of chiral boron containing amine-cyano(pyrrolyl-1)borane complexes. Preparation of (−)-(S)-α-phenylethylamine-(−)-cyano(pyrrolyl-1)borane and (+)-(R)-α-phenylethylamine-(+)-cyano(pyrrolyl-1)borane
作者:Bëla Györi、József Emri
DOI:10.1016/s0022-328x(00)84799-3
日期:1982.10
Several amine-cyano(pyrrolyl)boranecomplexes [A · BH(NC4H4)CN] containing a chiral boron atom were prepared from the reactions of sodium cyanohydrodipyrrolylborate-tridioxane1 [NaBH(NC4H4)2CN · 3C4H8O2] with amine hydrochlorides as well as by base exchange from the appropriate 4-cyanopyridine complex [4-CNC5H4N · BH(NC4H4)CN]. Amines with an sp2 N atom give stable complexes of a wide range of basicity
若干胺氰基(吡咯基)硼烷配合物[A·BH(NC 4 H ^ 4)CN]含有手性硼原子被选自钠cyanohydrodipyrrolylborate-tridioxane的反应制备1 [加入NaBH(NC 4 H ^ 4)2 CN·3C 4 H 8 O 2 ]与胺盐酸盐以及通过从适当的4-氰基吡啶络合物[4-CNC 5 H 4 N·BH(NC 4 H 4)CN]进行碱交换。带有sp 2 N原子的胺可提供多种碱度的稳定络合物(p K a= 0.8-9.7),与sp 3杂化N的胺类相反,后者只有更强的碱(p K a 7.3 7.3)才能产生稳定的络合物(主要是仲胺和叔胺)。这些化合物在中性和碱性介质中会发生水解,而在强酸中,它们会通过在吡咯基的α-C原子上质子化产生稳定的硼离子。化合物(-)-(S)-α-苯乙胺-(-)-氰基吡咯烷硼烷和(+)-(R)-α-苯乙胺-(+)-氰基吡咯烷硼烷已制备成纯净
Pharmacologically active guanidine compounds
申请人:Smith Kline & French Laboratories Limited
公开号:US03950333A1
公开(公告)日:1976-04-13
The compounds are substituted thioalkyl-, aminoalkyl- and oxyalkyl-guanidines which are inhibitors of histamine activity.
这些化合物是取代的硫代烷基、氨基烷基和氧烷基胍,它们是组胺活性的抑制剂。
Inhibitors of prenyl-protein transferase
申请人:Merck & Co., Inc.
公开号:US06297239B1
公开(公告)日:2001-10-02
The present invention is directed to compounds which inhibit a prenyl-protein transferase (FTase) and the farnesylation of the oncogene protein Ras. The invention is further directed to chemotherapeutic compositions containing the compounds of this invention and methods for inhibiting a prenyl-protein transferase and the prenylation of the oncogene protein Ras.
Solvent-free <i>N</i>-Boc deprotection by <i>ex situ</i> generation of hydrogen chloride gas
作者:Rik H. Verschueren、Philippe Gilles、Seger Van Mileghem、Wim M. De Borggraeve
DOI:10.1039/d1ob00728a
日期:——
protecting group is described, using down to near-stoichiometric amounts of hydrogenchloridegas in solvent-free conditions. We demonstrate the ex situ generation of hydrogenchloridegas from sodium chloride and sulfuric acid in a two-chamber reactor, introducing a straightforward method for controlled and stoichiometric release of HCl gas. The solvent-free conditions allow deprotection of a wide variety of
描述了一种有效、可扩展且可持续的方法,用于在无溶剂条件下使用低至接近化学计量的氯化氢气体对氨基甲酸叔丁酯 ( N -Boc) 保护基团进行定量脱保护。我们展示了在两室反应器中从氯化钠和硫酸异位生成氯化氢气体,介绍了一种用于控制和化学计量释放 HCl 气体的简单方法。无溶剂条件允许对多种N进行脱保护-Boc衍生物以定量产率获得盐酸盐。该程序消除了对任何后处理或纯化步骤的需要,为标准方法提供了一种简单的绿色替代方案。由于无溶剂、无水条件,该方法对酸敏感官能团具有高耐受性,并提供扩展的官能团正交性。