| 1. |
- Aeluri, Madhu, et al.
(author)
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An Intramolecular Heck Approach To Obtain 17-Membered Macrocyclic Diversity and the Identification of an Antiangiogenesis Agent from a Zebrafish Assay
- 2013
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In: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :19, s. 3955-3958
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Journal article (peer-reviewed)abstract
- We report a practical and modular approach to obtain two different types of 17-membered ring macrocyclic compounds through an intramolecular Heck reaction. These macrocyclic compounds are functionalized, that is, they contain two contiguous stereogenic hydroxy functional groups and an amino acid moiety in the macrocyclic ring skeleton. The macrocycles were then screened against a zebrafish assay to determine the antiangiogenesis activity of these small molecules. Macrocyclic compound 2.2a was identified as a potent inhibitor at 2.5 M, whereas its acyclic precursor and the other related macrocyclic compounds did not show any effect.
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| 2. |
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| 3. |
- Andersson, Claes-Henrik, et al.
(author)
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Reproducibility and efficiency of carbon nanotube end-group generation and functionalization
- 2009
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In: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; 26, s. 4421-4428
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Journal article (peer-reviewed)abstract
- In a systematic fashion, several methods for esterification and amidation of single-walled carbon nanotubes have been evaluated with focus on efficiency and reproducibility in forming covalently functionalized products soluble in organic media. The outcome of transformations was determined using IR, Raman and NMR spectroscopy and by thermogravimetric analysis (TGA). Amidation proceeding via a SWNT-(COCl)(n) intermediate yielded the expected covalent product, whereas carboxylate salt formation dominated with other attempted methods. Esterification was achieved via the acyl chloride method and via alkylation of SWNT-(COO-)(n), the latter being the more efficient method. A non-covalent solubilizing interaction was obtained for RNH2 but not for ROH (R = octadecyl), proving that the most important non-covalent interaction between oxidatively cleaned SWNTs and octadecylamine is a salt formation. The outcome of the secondary functionalization of carboxyl units is highly reproducible for experiments carried out on the same batch of SWNT-(COOH)(n). Normalization of the outcome of the secondary functionalization to the composition of the different batches of starting materials reveals an overall high reproducibility of the secondary function alizations. The differences in outcome related to different commercial SWNT batches from the same synthetic procedure is negligible compared to that resulting from differences in overall carboxyl content after the primary HNO3 oxidative cleaning step. Hence, the composition of purified SWNT starting materials always needs to be assessed, in particular before drawing any conclusions concerning differences in outcome from reaction systems involving different sources of SWNT material.
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| 4. |
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| 5. |
- Angelin, Marcus, et al.
(author)
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Crystallization Driven Asymmetric Synthesis of Pyridine β-Nitroalcoholsvia Discovery-Oriented Self-Resolution of a Dynamic System
- 2010
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In: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; 33, s. 6315-6318
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Journal article (peer-reviewed)abstract
- The study of dynamic nitroaldol systems aided the discovery of a diastereoselective crystallization process through amplification of 2-nitro-1-(pyridine-4-yl)propan-1-ol. The phenomenon was further developed into an effective procedure for asymmetic synthesis of pyridine-nitroalcohols and several substrates were screened to this end. These results demonstrate how work with larger dynamic systems facilitates and increases the likelihood of serendipitous discoveries.
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| 6. |
- Angelin, Marcus, et al.
(author)
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Direct, mild, and selective synthesis of unprotected dialdo-glycosides
- 2006
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In: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :19, s. 4323-4326
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Journal article (peer-reviewed)abstract
- A direct and highly convenient organocatalytic method for the preparation of 1,5-dialdo-pyranosides and 1,4-dialdo-furanosides is presented. The method relies on the chemoselective properties of TEMPO in combination with trichloroisocyanuric acid under very mild, basic conditions. Unprotected glycosides are prepared in a single step in high yields and are efficiently purified with the use of solid-phase imine capture. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).
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| 7. |
- Ankner, Tobias, et al.
(author)
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Mild Oxidative Cleavage of 9-BBN-Protected Amino Acid Derivatives
- 2015
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In: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :17, s. 3767-3770
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Journal article (peer-reviewed)abstract
- Protection of the amino acid moiety using 9-BBN is an effective method to enable side chain manipulations in synthesis of complex amino acids. We investigated the standard, mild method for deprotection of the 9-BBN group in methanolic chloroform, and found that it relies on a slow oxidation mediated by molecular oxygen. Building on this insight, we have developed a method that allows for a fast and selective deprotection using simple peroxy acid reagents. After Fmoc protection, products were isolated in >90% yield for a series of amino acid derivatives, including a galactosylated derivative of hydroxylysine.
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| 8. |
- Antonacci, G., et al.
(author)
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Manganese-Catalyzed Cross-Coupling of Aryl Halides and Grignard Reagents by a Radical Mechanism
- 2017
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In: European Journal of Organic Chemistry. - : Wiley. - 1434-193X. ; :32, s. 4758-4764
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Journal article (peer-reviewed)abstract
- The substrate scope and the mechanism have been investigated for the MnCl2-catalyzed cross-coupling reaction between aryl halides and Grignard reagents. The transformation proceeds rapidly and in good yield when the aryl halide component is an aryl chloride containing a cyano or an ester group in the para position or a cyano group in the ortho position. A range of other substituents gave no conversion of the aryl halide or led to the formation of side products. A broader scope was observed for the Grignard reagents, where a variety of alkyl- and arylmagnesium chlorides participated in the coupling. Two radical-clock experiments were carried out, and in both cases an intermediate aryl radical was successfully trapped. The cross-coupling reaction is therefore believed to proceed by an S(RN)1 mechanism, with a triorganomanganate complex serving as the most likely nucleophile and single-electron donor. Other mechanistic scenarios were excluded based on the substrate scope of the aryl halide.
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| 9. |
- Aplander, Karolina, et al.
(author)
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Asymmetric Lewis Acid Catalysis in Water: alpha-Amino Acids as Effective Ligands in Aqueous Biphasic Catalytic Michael Additions
- 2009
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In: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :6, s. 810-821
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Journal article (peer-reviewed)abstract
- This article explores the potential of native a-amino acids as chiral ligands in aqueous asymmetric Lewis acid catalysis, employing the C-C bond forming Michael addition as a model reaction. Some insights are provided regarding the details of Yb(OTf)(3)/alpha-amino acid-catalyzed Michael additions in water through new kinetic data as well as studies on how both yield and selectivity are influenced by variations in metal/ligand ratio, pH, temperature, and structure of the a-amino acid, Through this investigation it was found that reaction conditions that require only 5 mol-% of the Lewis acid, provides enantiomeric excesses of up to 79 % and is applicable to a wider range of donors and acceptors than previously demonstrated. Importantly, it was also demonstrated that the a-amino acid complexed ytterbium. catalyst might have potential for large-scale applications as it displays not only large ligand accelerations, but also good solubility and stability in water. It can be recycled multiple times without appreciable loss of activity. The result is a promising example of a water-compatible chiral Lewis acid. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
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| 10. |
- Appendino, G, et al.
(author)
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The reductive fragmentation of 7-hydroxy-9,10-dioxotaxoids.
- 2003
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In: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; 2003:22, s. 4422-4431
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Journal article (peer-reviewed)abstract
- The retro-aldol reductive fragmentation of different structural types of 7-hydroxy-9,10-dioxotaxoids was investigated, showing that the reaction is typical of taxanes and requires cerium(III) promotion with NaBH4 in protic medium and alkylboron (aluminium) hydrides in aprotic solvents. The resulting 7,8-seco-taxanes are key intermediates for the synthesis of a novel class of anticancer taxanes endowed with a unique pattern of in vivo biological activity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
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