| 1. |
- Lake, F., et al.
(författare)
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Sulfonamide ligands from chiral aziridines - Application to the titanium-mediated addition of diethylzinc to benzaldehyde
- 2002
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Ingår i: European Journal of Organic Chemistry. - 1434-193X .- 1099-0690. ; :18, s. 3179-3188
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Tidskriftsartikel (refereegranskat)abstract
- A modular approach was developed for the preparation of chiral, enantiopure sulfonamide ligands with C-1, C-2, and C-3 symmetry by ring opening of chiral N-sulfonylaziridines with ammonia, primary amines, and diamines. The new ligands were assessed in the titanium-mediated addition of diethylzinc to benzaldehyde, giving the product with selectivities up to 76% ee. ((C) Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).
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| 2. |
- Larsson, Michael, et al.
(författare)
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Syntheses of the sixteen stereoisomers of 3,7,11-trimethyl-2-tridecanol, including the (2S,3S,7S,11R) and (2S,3S,7S,11S) stereoisomers identified as pheromone precursors in females of the pine sawfly Microdiprion pallipes (Hymenoptera : Diprionidae). : Diprionidae)
- 2001
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Ingår i: European Journal of Organic Chemistry. - 1434-193X .- 1099-0690. ; :2, s. 353-363
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Tidskriftsartikel (refereegranskat)abstract
- All sixteen stereoisomers of 3,7,11-trimethyl-2-tridecanol were synthesised in high stereoisomerical purities (> 95%), for use in the identification of the stereoisomers present in females of the pine sawfly Microdiprion pallipes (Fallen) (Hymenoptera: Diprionidae) as the precursor of the actual sex pheromone (which is the propionate), and also for investigation of the biological activities of the esters. The key step in the syntheses was the coupling of each of the enantiomers of cis-3,4-dimethyl-gamma -butyrolactone with each of the four pure stereoisomers of 1-lithio-2,6-dimethyloctanes. The four corresponding alcohols were obtained by lipase-catalysed (Amano PS) kinetic separation, based on selective acylation of either (2R/S,6S)- or (2R/S,GR)-2,6-dimethyl-1-octanol (obtained from the optically pure enantiomers of citronellal). Additionally, a mixture of the 16 possible stereoisomers of 3,7,11-trimethyl-2-tridecanol was also prepared.
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| 3. |
- Stranne, R., et al.
(författare)
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Pyrrolidinopyridines in palladium-catalyzed allylic substitutions - Conformation of the ligand
- 2001
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Ingår i: European Journal of Organic Chemistry. - 1434-193X .- 1099-0690. ; :11, s. 2191-2195
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Tidskriftsartikel (refereegranskat)abstract
- The (R,R)-2-[(2,5-dimethylpyrrolidin-1-yl)methyl]pyridines 4, 5, and 6 carrying a 2-hydroxyalkyl, 2-alkoxyalkyl or 2-siloxyalkyl substituent in the 6-position of the pyridine ring were prepared and assessed in palladium-catalyzed allylations of 1,3-diphenylpropenyl acetate with malonate. All ligands having g-substituents with an S absolute configuration afforded the product with an R configuration in 80-84% ee, whereas those having substituents with an R absolute configuration gave the opposite product with a selectivity depending on the nature of the substituent (8-74% ee). It is believed that the enantioselectivity is dependent on the conformation of that substituent.
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| 4. |
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| 5. |
- Micskei, K., et al.
(författare)
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Reactions of nepenthone with chromium(II) reagents in neutral aqueous medium
- 1999
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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :1, s. 149-153
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Tidskriftsartikel (refereegranskat)abstract
- A synthetic method for the selective transformations of a selected morphine alkaloid in neutral aqueous medium is introduced. Full diastereoselectivity was achieved by the transformation of nepenthone (1) with [Cr(ida)(H2O)3] into 2a (20R) showing a complementary method as compared to the reactions with classical reagents to result in 2b (20S). A new unexpected morphine derivative 3 was prepared by a ligand-induced modification of the reaction which involves an unprecedented rearrangement.
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| 6. |
- Aeluri, Madhu, et al.
(författare)
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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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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :19, s. 3955-3958
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Tidskriftsartikel (refereegranskat)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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| 7. |
- Andersson, Claes-Henrik, et al.
(författare)
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Reproducibility and efficiency of carbon nanotube end-group generation and functionalization
- 2009
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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; 26, s. 4421-4428
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Tidskriftsartikel (refereegranskat)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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| 8. |
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| 9. |
- Angelin, Marcus, et al.
(författare)
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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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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; 33, s. 6315-6318
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Tidskriftsartikel (refereegranskat)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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| 10. |
- Angelin, Marcus, et al.
(författare)
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Direct, mild, and selective synthesis of unprotected dialdo-glycosides
- 2006
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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :19, s. 4323-4326
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Tidskriftsartikel (refereegranskat)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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