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  • 1.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Livendahl, Madeleine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Fine-tuning catalytic activity and selectivity-[Rh(amino acid thioamide)] complexes for efficient ketone reduction2009Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, nr 46, s. 6321-6324Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Amino acid-derived thioamides are prepared and evaluated as ligands in the rhodium-catalyzed asymmetric transfer hydrogenation of ketones in 2-propanol. It is found that increasing the steric bulk at the C-terminus of the ligand had a positive impact on both activity and selectivity in the reduction reaction. In order to find the optimum catalyst, a study is performed on a series of thioamide ligands having substituents of varying size.

  • 2. Ahmad, Anees
    et al.
    Scarassati, Paulo
    Jalalian, Nazli
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Universidade de São Paulo, Brazil.
    Olofsson, Berit
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Silva, Luiz F., Jr.
    Oxidative rearrangement of alkenes using in situ generated hypervalent iodine(III)2013Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 54, nr 43, s. 5818-5820Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel protocol for the oxidative rearrangement of alkenes using in situ generated hypervalent iodine(III) was developed. This approach uses inexpensive, readily available, and stable chemicals (PhI, mCPBA, and TsOH) giving rearrangement products in yields comparable to those obtained using the more expensive commercially available [hydroxy(tosyloxy)iodo]benzene [HTIB or Koser's reagent]. Additionally, an alternative protocol for the synthesis of 1-methyl-2-tetralone through the one-step epoxidation/rearrangement of 4-methyl-1,2-dihydronaphthalene using mCPBA and TsOH was developed.

  • 3.
    Aydin, Juhanes
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Selander, Nicklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Strategies for fine-tuning the catalytic activity of pincer-complexes2006Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 47, nr 50, s. 8999-9001Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Various methoxy substituted pincer-complexes were prepared in order to study the substituent effects on the catalytic activity in palladium catalyzed opening of vinyl epoxides and boronation of cinnamyl alcohol. The results clearly show that methoxy substitution at the para-position of the pincer-complex leads to up to fourfold acceleration of the catalytic reactions, while substitution of the side-arms does not change the activity of the complex or leads to a slight deceleration of the catalytic processes.

  • 4.
    Bogár, Krisztián
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    High-yielding metalloenzymatic dynamic kinetic resolution of fluorinated aryl alcohols2007Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 48, nr 31, s. 5471-5474Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dynamic kinetic resolution (DKR) of various fluorinated aryl alcohols by a combination of lipase-catalyzed enzymatic resolution with in situ ruthenium-catalyzed alcohol racemization is described. (R)-Selective Candida antarctica lipase B (CALB) was employed for transesterification of different fluoroaryl alcohols in DKR reactions delivering the corresponding acetates in high yield (97%) with excellent enantiomeric excess (98%).

  • 5.
    Borén, Linnéa
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Leijondahl, Karin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dynamic Kinetic Asymmetric Transformation of 1,4-diols and Preparation of Trans-2,5-Disubstituted pyrrolidines2009Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, nr 26, s. 3237-3240Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dynamic kinetic asymmetric transformation (DYKAT) of a series of 1,4-diols is carried out with Candida antarctica lipase B (CALB), Pseudomonas cepacia lipase II (PS-C II), and a ruthenium catalyst. A β-chloro-substituted 1,4-diol is successfully transformed into an optically pure 1,4-diacetate, which is a highly useful synthetic intermediate. The usefulness of the optically pure 1,4-diacetates is demonstrated by the synthesis of enantiopure 2,5-disubstituted pyrrolidines.

  • 6.
    Csjernyik, Gábor
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bogár, Krisztián
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    New Efficient Ruthenium Catalysts for Racemization of Alcohols at Room Temperature2004Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 45, nr 36, s. 6799-6802Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    5-Pentaphenylcyclopentadienyl)RuCl(CO)2 was found to catalyze efficiently the racemization of chiral alcohols such as (S)-1-phenylethanol, (S)-1-phenylpropan-2-ol, (S)-4-phenylbutan-2-ol and (S)-4-methoxy-1-phenylethanol at room temperature in the presence of a base. The catalytic activity of three other Ru(II) complexes was also investigated. The effects of halide and solvent were studied as well.

  • 7.
    Danielsson, Marie
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Wahlström, Karolina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Undén, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Protection of the indole nucleus of tryptophan in solid-phase peptide synthesis with a dipeptide that can be cleaved rapidly at physiological pH2011Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 52, nr 44, s. 5876-5879Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The synthesis of a new derivative of tryptophan Fmoc-Trp(Boc-Sar-Sar)-OH is described. Fmoc-Trp(Boc-Sar-Sar)-OH is introduced into peptides by solid-phase peptide synthesis and during treatment with TFA at the end of the synthesis, the Boc group is cleaved and the peptide is obtained with the indole nucleus modified with the sarcosinyl-sarcosinyl (Sar-Sar) moiety. This modification will introduce a cationic charge that improves the solubility of the peptide during HPLC purification. The Sar-Sar moiety is cleaved upon exposure to physiological pH. The Boc-Sar-Sar group might, therefore, also find use in the design of pro-drugs of indole-containing compounds.

  • 8.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Gui-Ling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dziedzik, Pawel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rios, Ramón
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Vesely, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ekström, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    One-pot highly enantioselective catalytic Mannich-type reactions between aldehydes and stable α-amido sulfones: asymmetric synthesis of β-amino aldehydes and β-amino acids2010Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, nr 2, s. 234-237Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A highly enantioselective catalytic route to carbamate- and benzoate-protected beta-amino aldehydes and beta-amino acids is presented. The amino acid-catalyzed one-pot asymmetric reaction between unmodified aldehydes and alpha-amido sulfones gives the corresponding beta-amino compounds with up to 95:5 dr and 97-99%

  • 9.
    Dziedzic, Pawel
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bartoszewicz, Agnieszka
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Inorganic ammonium salts as catalysts for direct aldol reactions in the presence of water2009Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, nr 52, s. 7242-7245Artikkel i tidsskrift (Fagfellevurdert)
  • 10.
    Dziedzic, Pawel
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ibrahem, Ismail
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Direct catalytic asymmetric three-component Mannich reactions with dihydroxyacetone: enantioselective synthesis of amino sugar derivatives2008Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, nr 5, s. 803-807Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Highly enantioselective, amino acid-catalyzed, one-pot three-component asymmetric Mannich reactions between dihydroxyacetone, p-anisidine, and aldehydes are presented. The reactions proceeded with high chemo- and stereoselectivity and furnished the corresponding α,α′-dihydroxy-β-aminoketones in high yields with 82–95% ee.

  • 11.
    Edin, Michaela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Córdova, Armando
    Tandem enantioselective organo- and biocatalysis: a direct entry for the synthesis of enantiomerically pure aldols2004Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 45, s. 7697-7701Artikkel i tidsskrift (Fagfellevurdert)
  • 12.
    Eiríksdóttir, Emelía
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Langel, Ülo
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Rosenthal-Aizman, Katri
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    An improved synthesis of releasable luciferin-CPP conjugates2009Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, nr 33, s. 4731-4733Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have improved the synthesis of a previously published luciferin-linker, used in an assay enabling rapid real-time quantification of luciferin–CPP conjugate uptake and cytosolic cargo release. We also present the synthesis of a new luciferin-linker with the same conjugation ability. Both luciferin-linkers are now available via an efficient one-pot procedure.

  • 13.
    Erlandsson, Mikael
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Undén, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    3-(4-hydroxymethylphenylsulfanyl)propanoic acid (HMPPA) as a new safety catch linker in solid phase peptide synthesis2006Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 32, nr 7, s. 5829-5832Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new safety catch linker, 3-(4-hydroxymethylphenylsulfanyl)propanoic acid (HMPPA), is described for use in solid phase peptide synthesis. The linker is readily synthesized from commercially available chemicals in a more cost efficient way compared to similar reported linkers. The HMPPA linker is easily attached to an amino derivatized solid support followed by on-resin oxidation of the thioether to sulfoxide, thereby making the linker very stable towards strong acid treatment. Final resin cleavage is performed by reductive acidolysis.

  • 14.
    Fournière, Viviane
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Cumpstey, Ian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis of non-glycosidically linked selenoether pseudodisaccharides2010Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, nr 16, s. 2127-2129Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Non-glycosidically linked disaccharide mimetics with a selenoether functionality linking the two monosaccharide residues have been synthesised. Protected Glc(Se3–3)Glc, Glc(Se3–6)Glc and Glc(Se3–6)Man structures were obtained. Selenium was introduced by displacement of carbohydrate sulfonates with a selenobenzoate anion. Conversion into diselenides by methanolysis of the benzoate and aerial oxidation was followed by reduction of the diselenides to selenolates, and in situ displacement of a second carbohydrate sulfonate in an SN2 reaction to give selenoethers. Glc(Se3–3)Glc and Glc(Se3–6)Glc were also obtained in deprotected form.

  • 15.
    Frigell, Jens
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Cumpstey, Ian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    First synthesis of 4a-carba-beta-D-galactofuranose2007Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 48, nr 52, s. 9073-9076Artikkel i tidsskrift (Fagfellevurdert)
  • 16.
    Frigell, Jens
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Cumpstey, Ian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis of carbadisaccharide mimics of galactofuranosides2009Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, nr 36, s. 5142-5144Artikkel i tidsskrift (Fagfellevurdert)
  • 17.
    Hoben, Christine E.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kanupp, Lisa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Practical chemoenzymatic dynamic kinetic resolution of primary amines via transfer of a readily removable benzyloxycarbonyl group2008Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, nr 6, s. 977-979Artikkel i tidsskrift (Fagfellevurdert)
  • 18. ibrahem, Ismail
    et al.
    Samec, Joseph S M
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdiva, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Enantioselective addition of aldehydes to amines via combined catalytic biomimetic oxidation and organocatalytic C-C- bond formation2005Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 46, nr 23, s. 3965-3968Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The biomimetic catalytic enantioselective addition of aldehydes to amines is reported. This was accomplished by combining biomimetic coupled catalytic aerobic oxidation of amines involving ruthenium-induced dehydrogenation and organocatalytic asymmetric Mannich reactions. The novel one-pot reactions furnished β-amino aldehyde and α-amino acid derivatives in high yields with excellent chemoselectivity and up to >99% ee.

  • 19.
    Jönsson, Daniel
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi och neurotoxikologi.
    Erlandsson, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi och neurotoxikologi.
    Undén, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi och neurotoxikologi.
    Solid-phase synthesis of oxygen-bridged tetrahydropyridones2001Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 42, nr 39, s. 6953-6956Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A solid-phase approach for the synthesis of oxygen-bridged tetrahydropyridones has been developed. A diamine is attached to Trt-Cl resin and condensed with different aliphatic or aromatic ketones and coumarin-3-carboxylic acid for 20 h and cleaved with 5% TFA in DCM, resulting in tri or tetracyclic products in moderate to high yield.

  • 20.
    Kjellgren, Johan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Synthesis of stereodefined vinyl-tetrahydropyran and vinyl-octahydrochromene derivatives via acetalization-cyclization of allylsilanes with aldehydes: Origin of the high stereoselectivity2002Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 43, nr 6, s. 1123-1126Artikkel i tidsskrift (Fagfellevurdert)
  • 21. Linde, Christian
    et al.
    Anderlund, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    The Effect of Phenolates in the Mn(salen)-Catalyzed Epoxidation Reaction2005Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 46, nr 33, s. 5597-5600Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    By addition of 2,4,6-tri-tert-butylphenolate in the Mn(salen) catalyzed epoxidation of cis-alkenes with iodosobenzene, essentially pure trans-epoxides can be obtained.

  • 22.
    Lindström, Ulf M.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Olofsson, Berit
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Somfai, Peter
    Microwave-assisted aminolysis of vinylepoxides1999Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 40, nr 52, s. 9273-9276Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Di- and trisubstituted vinyl epoxides in NH4OH were subjected to microwave irradn. affording the corresponding vicinal amino alcs. in high yields. The reaction is stereospecific and highly regioselective for addn. at the allylic carbon. [on SciFinder(R)]

  • 23.
    Lundberg, Helena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ruthenium-catalyzed asymmetric transfer hydrogenation of ketones in ethanol2011Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 52, nr 21, s. 2754-2758Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A ruthenium catalyst formed in situ by combining [Ru(p-cymene)Cl2]2 and an amino acid hydroxy-amide was found to catalyze efficiently the asymmetric reduction of aryl alkyl ketones under transfer hydrogenation conditions using ethanol as the hydrogen donor. The secondary alcohol products were obtained in moderate to good yields and with good to excellent enantioselectivity (up to 97% ee).

  • 24.
    Motwani, Hitesh V.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Kyushu University, Japan.
    Shimakoshi, Hisashi
    Golding, Bernard T.
    Törnqvist, Margareta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Hisaeda, Yoshio
    Alkylcobyrinate from sucralose and mechanistic aspects of its Co-C bond cleavage2014Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 55, nr 16, s. 2667-2670Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reaction of heptamethyl cob(I)yrinate with 1',6'-dichloro-1',6'-dideoxy-beta-D-fructofuranosyl-4-chloro-4-deoxy-alpha-D-galactopyranoside (sucralose) gave an alkylcobyrinate, heptamethyl-6'-[alpha-D-galactopyranoside- 1'-chloro-1',6'-dideoxy-beta-D-fructofuranosyl-4-chloro-4-deoxy]cobyrinate perchlorate, [(Suc)Cob(III) 7C(1)ester]ClO4. Cleavage behavior of Co-C bond of the alkylcobyrinate was investigated under various conditions (hv, H+ and reduction) using UV-vis spectroscopy combined with the EPR spin-trapping technique, and by cyclic voltammetry.

  • 25.
    Olofsson, Berit
    et al.
    Royal Institute of Technology, Sweden.
    Somfai, Peter.
    Royal Institute of Technology, Sweden.
    Determination of the relative configuration of vic-amino alcohols2003Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 44, nr 6, s. 1279-1281Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A large set of syn- and anti-1,2-amino alcs. has been synthesized. Upon comparison of the CHO and CHN 1H NMR shifts a general trend has been obsd., making it possible to det. the relative configuration of 1,2-amino alcs. without derivatization or shift reagents.

  • 26.
    Rosenthal, Katri
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi och neurotoxikologi.
    Erlandsson, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi och neurotoxikologi.
    Undén, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi och neurotoxikologi.
    4-(3-Hydroxy-4-methylpentyl)phenylacetic acid as a new linker for the solid phase synthesis of peptides with Boc chemistry1999Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 40, nr 2, s. 377-380Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The anchoring the first amino acid in Boc chemistry to a 4-(3-hydroxy-4-methylpentyl)phenylacetic acid linker is described and compared to the conventional Pam resin. The peptidyl-4-(4-methyl-3-pentoxy)phenylacetamide linkage is slightly more stable to TFA than the Pam linker but in contrast to the Pam linker stable to cleavage of benzylic protective groups with TFMSA/DMS/TFA mixtures. This allows a mild and convenient two step deprotection procedure using the “low TFMSA-high HF”. In HF this new linker reacts preferentially in an intramolecular reaction forming a tetrahydronaphthalene derivative.

  • 27.
    Stamatov, Stephan D.
    et al.
    -.
    Stawinski, Jacek
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. -.
    Regioselective and stereospecific opening of an oxirane system mediated by trifluoroacetic acid and halide anions. A new direct approach to C3-vicinal halohydrins.: -2007Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, ISSN -, Vol. 48, nr -, s. 1887-1889Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    -

  • 28.
    Thalén, Lisa K.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Hedberg, Martin H.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Recycling of pipecoloxylidide via racemization2010Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, nr 52, s. 6802-6805Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A method for the racemization of pipecoloxylidide with a ruthenium catalyst has been developed. This racemization method can be implemented in an integrated process that combines the separation of two enantiomers with racemization of the undesired enantiomer.

  • 29.
    Vesely, Jan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dziedzic, Pawel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Aza-Morita-Baylis-Hillman-type reactions: highly enantioselective organocatalytic addition of unmodified alpha-beta-unsaturated aldehydes to N-Boc protected imines2007Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 48, nr 39, s. 6900-6904Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Highly enantioselective catalytic routes to Boc protected aza-Morita-Baylis-Hiliman-type products are presented. The organocatalytic asymmetric reactions between unmodified alpha,beta-unsaturated aldehydes and N-Boc protected aryl imines proceed with excellent chemo- and enantioselectivity to give the corresponding compounds in good yields with 97-99% ee

  • 30.
    Wahlström, Karolina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Planstedt, Ove
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Undén, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    A carbamoyl-protective group for tyrosine that facilitatespurification of hydrophobic synthetic peptides2008Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, nr 23, s. 3779-3781Artikkel i tidsskrift (Fagfellevurdert)
  • 31.
    Wahlström, Karolina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Planstedt, Ove
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Undén, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Synthesis and purification of aggregation-prone hydrophobicpeptides by the incorporation of an Fmoc dipeptide withthe peptide bond protected with a modified 2-hydroxy-4-methoxybenzyl (Hmb) group2008Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, nr 24, s. 3921-3924Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The dipeptide Fmoc-Val-(2-hydroxy-4-methoxybenzyl)Gly-OBzl was synthesized and the 2-hydroxyl group carbamoylated to give a Boc-N(CH(3))CH(2)CH(2)N(CH(3))CO-, (Boc-Nmec-) modification of the 2-hydroxy-4-methoxybenzyl (Hmb) group. After catalytic hydrogenation and purification, the resulting dipeptide Fmoc-Val-(Boc-Nmec-Hmb)Gly-OH was used in solid phase peptide synthesis. During treatment with TFA, the peptide was released from the resin and the Boc group cleaved. The peptide could then be purified with an alkylated peptide bond carrying a cationic charge that both increased the solubility of the peptide during the purification steps and facilitated analysis by MALDI-TOF mass spectrometry. The Nmec group was cleaved by intramolecular cyclization under slightly alkaline conditions, followed by cleavage of the Hmb group by TFA to give the fully deprotected peptide.

  • 32.
    Wahlström, Karolina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Undén, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    A new protecting group for tryptophan in solid-phase peptide synthesis which protectsagainst acid-catalyzed side reactions and facilitates purification by HPLC2009Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, nr 24, s. 2976-2978Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The indole nucleus of Z-Trp-OBzl is modified by acylation of the indole nitrogen using Boc-N-methyl butyric acid followed by catalytic hydrogenation and introduction of the Fmoc group. The resulting derivative, Fmoc-Trp(Boc-Nmbu)-OH, is incorporated into peptide chains via solid-phase peptide synthesis (SPPS). After assembly of the peptide chain, the Boc group is cleaved by treatment with TFA. The peptide is isolated with the tryptophan residue modified with a cationic 4-(N-methylamino) butanoyl group, which improves the solubility of the peptide during HPLC purification. On treatment of the purified peptide at pH 9.5, the Nmbu group undergoes an intramolecular cyclization reaction; this results in the fully deprotected peptide and N-methylpyrrolidone.

  • 33. Wieczorek, Birgit
    et al.
    Träff, Annika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Krumlinde, Patrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dijkstra, Harm P.
    Egmond, Maarten R.
    van Koten, Gerard
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Klein Gebbink, Robertus J. M.
    Covalent anchoring of a racemization catalyst to CALB-beads: towards dual immobilization of DKR catalysts2011Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 52, nr 14, s. 1601-1604Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The preparation of a heterogeneous bifunctional catalytic system, combining the catalytic properties of an organometallic catalyst (racemization) with those of an enzyme (enantioselective acylation) is described. A novel ruthenium phosphonate inhibitor was synthesized and covalently anchored to a lipase immobilized on a solid support (CALB, Novozym® 435). The immobilized bifunctional catalytic system showed activity in both racemization of (S)-1-phenylethanol and selective acylation of 1-phenylethanol.

  • 34.
    Zhao, Gui-Ling
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dziedzic, Pawel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ullah, Farman
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Organocatalytic enantioselective domino synthesis of highly functionalized cyclohexanes with an all-carbon quaternary stereocenter2009Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, nr 26, s. 3458-3462Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A highly enantioselective organocatalytic domino Michael/aldol reaction is presented. The reaction is catalyzed by chiral amines and gives access to highly functionalized cyclohexanes with one all-carbon quaternary stereocenter and multiple chiral stereocenters in high yields and 83–98% ee.

  • 35.
    Zhu, Mingzhao
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lin, Shuangzheng
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Gui-Ling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Organocatalytic diastereoselective dibromination of alkenes2010Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, nr 20, s. 2708-2712Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A highly diastereoselective pyrrolidine-promoted dibromination of alkenes by combination of NBS and succinimide is presented. The pyrrolidine-mediated dibromination of alkenes is higly anti-selective and gives the corresponding products in moderate to high yields and up to >25:1 dr.

1 - 35 of 35
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