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  • 1.
    Bhaskaran, Nimesh
    et al.
    Karolinska University Hospital.
    Iwahana, Hiroyuki
    Karolinska University Hospital.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Hellman, Ulf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Souchelnytskyi, Serhiy
    Karolinska University Hospital.
    Novel post-translational modifications of Smad2 identified by mass spectrometry2008In: Central European Journal of Biology, ISSN 1895-104X, E-ISSN 1644-3632, Vol. 3, no 4, p. 359-370Article in journal (Refereed)
    Abstract [en]

    Smad2 is a crucial component of transforming growth factor-b (TGFb) signaling, and is involved in the regulation of cell proliferation,death and differentiation. Phosphorylation, ubiquitylation and acetylation of Smad2 have been found to regulate its activity. We usedmass spectrometry to search for novel post-translational modifications (PTMs) of Smad2. Peptide mass fingerprinting (PMF) indicatedthat Smad2 can be acetylated, methylated, citrullinated, phosphorylated and palmitoylated. Sequencing of selected peptides validatedmethylation at Gly122 and hydroxylation at Trp18 of Smad2. We also observed a novel, so far unidentified modification at Tyr128 andTyr151. Our observations open for further exploration of biological importance of the detected PTMs.

  • 2.
    Diesen, Jarle Sidney
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Asymmetric Hydrogenations of Imines, Vinyl Fluorides, Enol Phosphinates and Other Alkenes Using N,P-Ligated Iridium Complexes2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The research described in this thesis is directed toward the efficient, enantioselective synthesis of chiral products that have useful functionality. This goal was pursued through catalytic asymmetric hydrogenation, a reaction class that selectively introduces one or two stereocenters into a molecule in an atom-efficient step. This reaction uses a small amount (often <1 mol%) of a chiral catalyst to impart stereoselectivity to the product formed. Though catalytic asymmetric hydrogenation is not a new reaction type, there remain many substrate classes for which it is ineffective. The present thesis describes efforts to extend the reaction to some of these substrates classes. Some of the products synthesized in these studies may eventually find use as building blocks for the production of chiral pharmaceuticals, agrochemicals, or flavouring or colouring agents. However, the primary and immediate aim of this thesis was to develop and demonstrate new catalysts that are rapid and effective in the asymmetric hydrogenation of a broad range of compounds.

    Paper I describes the design and construction of two new, related chiral iridium compounds that are catalysts for asymmetric hydrogenation. They each contain an N,P-donating phosphinooxazoline ligand that is held together by a rigid bicyclic unit. One of these iridium compounds catalyzed the asymmetric hydrogenation of acyclic aryl imines, often with very good enantioselectivities. This is particularly notable because acyclic imines are difficult to reduce with useful enantioselectivity. The second catalyst was useful for the asymmetric hydrogenation of two aryl olefins. In Paper II, the class of catalysts introduced into Paper I is expanded to include many more related compounds, and these are also applied to the asymmetric hydrogenation of prochiral imines and olefins. By studying a range of related catalysts that differ in a single attribute, we were able to probe how different parts of the catalyst affect the yield and selectivity of the hydrogenation reactions.

    Whereas iridium catalysts had been applied to the asymmetric hydrogenation of imines and largely unfunctionalized olefins prior to this work (with varied degrees of success), they had not been used to reduce fluoroolefins. Their hydrogenation, which is discussed in Paper III, was complicated by concomitant defluorination to yield non-halogenated alkanes. To combat this problem, several iridium-based hydrogenation catalysts were applied to the reaction. Two catalysts stood out for their ability to produce chiral fluoroalkanes in good enantioselectivity while minimizing the defluorination reaction, and one of these bore a phosphinooxazoline ligand of the type described in Papers I and II.

    Enol phosphinates are another class of olefins that had not previously been subjected to iridium-catalyzed asymmetric hydrogenation. They do, however, constitute an attractive substrate class, because the product chiral alkyl phosphinates can be transformed into chiral alcohols or chiral phosphines with no erosion of enantiopurity. Iridium complexes of the phosphinooxazoline ligands described in Papers I and II were extremely effective catalysts for the asymmetric hydrogenation of enol phosphinates. They produced alkyl phosphinates from di- and trisubstituted enol phosphinate, β-ketoester-derived enol phosphinates, and even purely alkyl-substituted enol phopshinates, in very high yields and enantioselectivities.

    List of papers
    1. Application of Phosphine-Oxazoline Ligands in Ir-Catalyzed Asymmetric Hydrogenation of Acyclic Aromatic N-Arylimines
    Open this publication in new window or tab >>Application of Phosphine-Oxazoline Ligands in Ir-Catalyzed Asymmetric Hydrogenation of Acyclic Aromatic N-Arylimines
    2004 In: Organic Letters, Vol. 6, no 21, p. 3825-3827Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-97350 (URN)
    Available from: 2008-05-13 Created: 2008-05-13Bibliographically approved
    2. Hydrogenation of Imines and Olefins Using Phosphine-Oxazoline Iridium Complexes as Catalysts
    Open this publication in new window or tab >>Hydrogenation of Imines and Olefins Using Phosphine-Oxazoline Iridium Complexes as Catalysts
    2006 In: Chemistry-A European Journal, Vol. 12, no 8, p. 2318-2328Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-97351 (URN)
    Available from: 2008-05-13 Created: 2008-05-13Bibliographically approved
    3. Iridium-Catalyzed Asymmetric Hydrogenation of Fluorinated Olefins Using N,P-Ligands: A struggle with hydrogenolysis and selectivity
    Open this publication in new window or tab >>Iridium-Catalyzed Asymmetric Hydrogenation of Fluorinated Olefins Using N,P-Ligands: A struggle with hydrogenolysis and selectivity
    2007 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 129, no 15, p. 4536-4537Article in journal (Refereed) Published
    Abstract [en]

    To broaden the substrate scope of asymmetric iridium-catalyzed hydrogenation, fluorine-functionalized olefins were synthesized and hydrogenated with iridium complexes. Preliminary results showed high levels of fluorine elimination together with low selectivity. The loss of vinylic fluorine at first seemed difficult to handle, but further studies revealed that a catalyst with an azanorbornyl scaffold in the ligand gave more promising results. With this in mind, a new ligand was developed. This gave among the best results published to date for fluorine asymmetric hydrogenation, yielding high conversion and very high ee's with very little fluorine elimination. Further increasing the selectivity, the trials also revealed that tetrasubstituted fluorine-containing olefins can be hydrogenated with high ee's, despite that this class of compounds has usually shown low reactivity in this reaction type.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-97352 (URN)10.1021/ja0686763 (DOI)000245739700016 ()17375924 (PubMedID)
    Available from: 2008-05-13 Created: 2008-05-13 Last updated: 2017-12-14Bibliographically approved
    4. Asymmetric Hydrogenation of Di and Trisubstituted Enol Phosphinates with N,P-Ligated Iridium Complexes
    Open this publication in new window or tab >>Asymmetric Hydrogenation of Di and Trisubstituted Enol Phosphinates with N,P-Ligated Iridium Complexes
    2008 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 130, no 16, p. 5595-5599Article in journal (Refereed) Published
    Abstract [en]

    The iridium-catalyzed asymmetric hydrogenation of various di- and trisubstituted enol phosphinates has been studied. Excellent enantioselectivities (up to >99% ee) and full conversion were observed for a range of substrates with both aromatic and aliphatic side chains. Enol phosphinates are structural analogues of enol acetates, and the hydrogenated alkyl phosphinate products can easily be transformed into the corresponding alcohols with conservation of stereochemistry. We have also hydrogenated, in excellent ee, several purely alkyl-substituted enol phosphinates, producing chiral alcohols that are difficult to obtain highly enantioselectively from ketone hydrogenations.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-97722 (URN)10.1021/ja711372c (DOI)000255041400050 ()
    Available from: 2008-11-11 Created: 2008-11-11 Last updated: 2017-12-14Bibliographically approved
  • 3.
    Kushnir, Mark M
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Rockwood, Alan L
    Bergquist, Jonas
    Varshavsky, Marina
    Roberts, William L
    Yue, Bingfang
    Bunker, Ashely M
    Meikle, A Wayne
    High sensitivity tandem mass spectrometry assay for serum estrone and estradiol2008In: American Journal of Clinical Pathology, ISSN 0002-9173, E-ISSN 1943-7722, Vol. 129, no 4, p. 530-539Article in journal (Refereed)
    Abstract [en]

    High-sensitivity measurement of serum estrogens is important in adult and pediatric endocrinology and oncology. We developed a high-sensitivity liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for simultaneous measurement of estrone (E-1) and estradiol (E-2). Aliquots of 200 mu L of serum were spiked with internal standard, extracted, derivatized with dansyl chloride, and analyzed by LC-MS/MS using 2-dimensional chromatographic separation. Total imprecision for the method was less than 11%; the limit of quantitation was 1 pg/mL. Reference intervals were established with samples from more than 900 healthy postmenopausal women, men, girls, and boys. Concentrations of estrogens in children reached adult levels by Tanner stage 3. In men and postmenopausal women, the median concentrations of total estrogens (E-1 + E-2) were 39 and 22 pg/mL, and the median E-2/E-1 ratios were 0.98 and 0.55, respectively. The method requires a small sample volume and has adequatesensitivity and specificity for analyzing estrogens in samples from postmenopausal women, men, and children.

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