| 1. |
- Allas, Ular, et al.
(författare)
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Antibacterial activity of the nitrovinylfuran G1 (Furvina) and its conversion products
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- 2-Bromo-5-(2-bromo-2-nitrovinyl) furan (G1 or Furvina) is an antimicrobial with a direct reactivity against thiol groups. It is active against Gram-positive and Gram-negative bacteria, yeasts and filamentous fungi. By reacting with thiol groups it causes direct damage to proteins but, as a result, is very short-living and interconverts into an array of reaction products. Our aim was to characterize thiol reactivity of G1 and its conversion products and establish how much of antimicrobial and cytotoxic effects are due to the primary activity of G1 and how much can be attributed to its reaction products. Stability of G1 in growth media as well as its conversion in the presence of thiols was characterized. The structures of G1 decomposition products were determined using NMR and mass-spectroscopy. Concentration-and time-dependent killing curves showed that G1 is bacteriostatic for Escherichia coli at the concentration of 16 mu g/ml and bactericidal at 32 mu g/ml. However, G1 is inefficient against non-growing E. coli. Addition of cysteine to medium reduces the antimicrobial potency of G1. Nevertheless, the reaction products of G1 and cysteine enabled prolonged antimicrobial action of the drug. Therefore, the activity of 2-bromo-5-(2-bromo-2-nitrovinyl) furan is a sum of its immediate reactivity and the antibacterial effects of the conversion products.
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| 2. |
- Danielsson, Jakob, et al.
(författare)
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1,3-Dipolar Cycloaddition of Azomethine Ylides to Aldehydes : Synthesis of anti alpha-Amino-beta-Hydroxy Esters
- 2011
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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :3, s. 607-613
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Tidskriftsartikel (refereegranskat)abstract
- A 1,3-dipolar cycloaddition reaction of azomethine ylides to aldehydes is described. The azomethine ylides, generated by thermal electrocyclic ring opening of aziridines, adds to aldehydes in good yields with moderate to good selectivities to furnish oxazolidines. The oxazolidines were subsequently hydrolyzed to the corresponding amino alcohols, giving the anti diastereomer as the major product.
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| 3. |
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| 4. |
- Toom, Lauri, 1980-
(författare)
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Bispidine Derivatives : Synthesis and Interactions with Lewis Acids
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, the improved synthesis and investigations into the properties of some 3,7-diazabicyclo[3.3.1]nonane (bispidine) derivatives are described. These compounds are structurally related to the naturally occurring lupanine alkaloids, they are of interest because of their cardiac antiarrhythmic function as well as their use as bases or ligands in organic chemical reactions. Their chemical properties are related to the presence of a rigid molecular scaffold with two nitrogen atoms that can be utilized for binding interactions with a variety of Lewis acids.An improved synthesis has been developed, providing access to bispidines via bispidinones while avoiding the use of highly toxic hydrazine, which is required as reducing agent in alternative methods.A series of bispidine derivatives with a variety of substituents were characterized regarding their basicity, which spans thirteen orders of magnitude. Correlations between structure and basicity are discussed and computational methods have been used to propose further derivatives with even higher basicity.The structures of several bispidine derivatives and their protonated forms have been characterized in the solid state by X-ray crystallography and in solution using NMR spectroscopy. Structure and solution dynamics in a sterically congested (π-allyl)palladium complex with a bispidine ligand have been investigated, revealing mechanistic insight into the dynamic process. Using a bulky bispidine as a temporary ligand for a (η3-propenyl) palladium complex, the novel adamantanoid [{(η3-propenyl)Pd}6(μ3-OH)4] cluster was prepared.
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| 5. |
- Toom, Lauri, et al.
(författare)
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Microwave-Assisted Raney Nickel Reduction of Bispidinone Thioketals to N,N’-Dialkylbispidines
- 2006
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Ingår i: Synthesis (Stuttgart). - : Georg Thieme Verlag KG. - 0039-7881 .- 1437-210X. ; :12, s. 2064-2068
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Tidskriftsartikel (refereegranskat)abstract
- A series of N,N′-dialkyl-3,7-diazabicyclo[3.3.1]nonanes was prepared by microwave-assisted reduction of a common dithiolane precursor with Raney nickel, using the corresponding alkanol as solvent. The method avoids the use of hydrazine.
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| 6. |
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| 7. |
- Toom, Lauri, et al.
(författare)
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Substituent Effects on the Basicity of 3,7-Diazabicyclo[3.3.1]nonanes
- 2006
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 71:19, s. 7155-7164
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Tidskriftsartikel (refereegranskat)abstract
- Basicity constants for a series of 3,7-diazabicyclo[3.3.1] nonane derivatives in acetonitrile with a variation over 13 orders of magnitude have been determined using a spectrophotometric titration technique. An excellent correlation between basicity and calculated proton affinities obtained at PCM-B3LYP/6-31+G-(d)//B3LYP/6-31G(d) level was found. The results are discussed in terms of substituent effects and compared to N-15 NMR chemical shifts.
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| 8. |
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