Research ArticleORGANIC CHEMISTRY

Reaction of H2 with mitochondria-relevant metabolites using a multifunctional molecular catalyst

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Science Advances  23 Oct 2020:
Vol. 6, no. 43, eabc0274
DOI: 10.1126/sciadv.abc0274
  • Fig. 1 Redrawing the map for the chemical transformation of Krebs cycle–relevant metabolites.

    (A) Single–[Ir] site–catalyzed hydrogenation and dehydration reactions in this work (black arrows and red text) and the original Krebs cycle (blue ring and gray text/arrows). Dashed arrows are proposed partial pathways in the hydrogenation of each substrate with Ir-a. ‡1,2-Propanediol (1,2-PDO; 36%) was also obtained. (B) Hydrogenation of cytoplasm metabolites (pale green ellipse). (C) Hydrogenation of the sugar-derived artificial feedstock LevA. For definitions of abbreviations and acronyms, see Fig. 2A. Isocitric acid (IsoCitA), oxalosuccinic acid (oxaloSucA), and succinyl-coenzyme A (succinylCoA) are rarely available.

  • Fig. 2 Summary of this work.

    (A) Renewable carbon feedstocks that afford various 1,4-BDO derivatives and 1,2-propanediol. Compound names in blue are Krebs cycle metabolites, while those marked with asterisks are possible feedstocks listed as top 30 value-added chemicals in the initial U.S. Department of Energy/the National Renewable Energy Laboratory report in 2004 (1). Succinic acid (SucA), malic acid (MliA), aspartic acid (AspA), oxaloacetic acid (OacA), tartaric acid (TarA), fumaric acid (FumA), maleic acid (MleA), maleic anhydride (MleAn), succinic anhydride (SucAn), γ-butyrolactone (GBL), itaconic acid (ItaA), 2-oxoglutaric acid (OglA), levulinic acid (LevA), aconitic acid (AcoA), and citric acid (CitA). (B) Single-crystal x-ray diffraction structure of Ir-a (left; Et2O included). Color key: Ir (blue), N (purple), P (orange), Cl (green), O (red), and H (white). See also fig. S1. [BPh4] is omitted for clarity. Ir and Ru complexes for hydrogenation tested in this work (right).

  • Fig. 3 Experimental results: Hydrogenation of various C4-, C5-, and C6-PCA feedstocks and phthalic acid using Ir-a and other metal complexes.

    (A) Hydrogenation of SucA with different Ir and Ru complexes. DMSO, dimethyl sulfoxide; NMR, nuclear magnetic resonance; GC, gas chromatography. (B) Hydrogenation of C4-feedstocks with Ir-a, Ir-b, and Ir-c. (C) Time conversion (yield) plots of the hydrogenation of FumA with Ir-a (1.5 mol %) without NaH. (D) Hydrogenation of C5 and C6 feedstocks with Ir-a. (E) Hydrogenation of phthalic acid (PhtA) with Ir-a.

  • Fig. 4 Representative H/D exchange and structural interconversion of Ir-a under different reaction conditions.

    (A) Heating in deuterated alcohols without H2. (B) Shorter heating with H2. (C) Prolonged heating in the presence of a DCA with H2. The values below each compound represent theoretical and experimental electron spray ionization–mass spectrometry values. (D) Prolonged heating with H2.

Supplementary Materials

  • Supplementary Materials

    Reaction of H2 with mitochondria-relevant metabolites using a multifunctional molecular catalyst

    Shota Yoshioka, Sota Nimura, Masayuki Naruto, Susumu Saito

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    This PDF file includes:

    • General information
    • Compound data of products
    • General procedures
    • Figs. S1 to S13
    • Tables S1 to S17
    • NMR and mass spectra
    • References

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