598-41-4Relevant articles and documents
Nickel(III) oxidation of its glycylglycylhistamine complex
Green, Brandon J.,Tesfai, Teweldemedhin M.,Margerum, Dale W.
, p. 3508 - 3514 (2004)
The doubly-deprotonated Ni(III) complex of Gly2Ha (where Ha is histamine) undergoes base-assisted oxidative self-decomposition of the peptide. At ≤ p[H+] 7.0, a major pathway is a two-electron oxidation at the a-carbon of the N-terminal glycyl residue. Major products (up to 73%) of this two-electron oxidation are glyoxylglycylhistamine and ammonia. Glyoxylglycylhistamine will decay to give isocyanatoacetylhistamine and formaldehyde. Two-electron oxidations of the second glycyl and histamine residues occur as minor pathways (12% of the total possible reaction). Above p[H+] 8.5, two Ni(III)-peptide complexes form an oxo bridge in the axial positions to give a reactive dimer species. This proximity allows the resulting Ni(III)-peptide radical intermediates to undergo peptide-peptide cross-linking at the N-terminal glycyl residues. The products found below p[H+] 7.0 are observed above p[H+] 8.5 as well, although in lower yields. In contrast to this work, NiIII(H- 2Gly2HisGly) undergoes a four-electron oxidation at the N-terminal glycyl residue. Oxidation at the internal glycyl and histidyl residues are not observed. The reactivity of NiIII(H -2Gly2Ha)+ is also different than Cu III(H-2Gly2Ha)+, which undergoes a two-electron oxidation at the histamine group with no peptide-peptide cross-linking in basic solution.
Preparation method of 2, 6-dichloropyrazine
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Paragraph 0034-0035, (2020/04/22)
The invention discloses a preparation method of 2, 6-dichloropyrazine. The method comprises the following steps: taking glycine and glyoxal as raw materials, carrying out ammoniation and cyclization reactions to prepare 2-hydroxypyrazine sodium; and reacting 2-hydroxypyrazine sodium with thionyl chloride under the catalytic action of N,N-diisopropylethylamine to prepare 2-chloropyrazine; wherein pyridine is used as a solvent, and 2-chloropyrazine is subjected to chlorination of chlorine to obtain 2,6-dichloropyrazine. The method has the advantages that the raw material namely glycine is cheapand easily available, and phosphorus oxychloride is not used as a chlorination reagent, so that the generation of organic phosphorus-containing wastewater is greatly reduced, and an effective way is provided for efficient green industrial production of 2, 6-dichloropyrazine.
Tuning the reactivity of nitriles using Cu(ii) catalysis-potentially prebiotic activation of nucleotides
Liu, Ziwei,Mariani, Angelica,Wu, Longfei,Ritson, Dougal,Folli, Andrea,Murphy, Damien,Sutherland, John
, p. 7053 - 7057 (2018/09/25)
During the transition from prebiotic chemistry to biology, a period of solution-phase, non-enzymatic activation of (oligo)nucleotides must have occurred, and accordingly, a mechanism for phosphate activation must have existed. Herein, we detail results of an investigation into prebiotic phosphate activation chemistry using simple, prebiotically available nitriles whose reactivity is increased by Cu2+ ions. Furthermore, although Cu2+ ions are known to catalyse the hydrolysis of phosphodiester bonds, we found this deleterious activity to be almost completely suppressed by inclusion of amino acids or dipeptides, which may suggest a productive relationship between protein and RNA from the outset.
Superactivity of MOF-808 toward Peptide Bond Hydrolysis
Ly, Hong Giang T.,Fu, Guangxia,Kondinski, Aleksandar,Bueken, Bart,De Vos, Dirk,Parac-Vogt, Tatjana N.
, p. 6325 - 6335 (2018/05/14)
MOF-808, a Zr(IV)-based metal-organic framework, has been proven to be a very effective heterogeneous catalyst for the hydrolysis of the peptide bond in a wide range of peptides and in hen egg white lysozyme protein. The kinetic experiments with a series of Gly-X dipeptides with varying nature of amino acid side chain have shown that MOF-808 exhibits selectivity depending on the size and chemical nature of the X side chain. Dipeptides with smaller or hydrophilic residues were hydrolyzed faster than those with bulky and hydrophobic residues that lack electron rich functionalities which could engage in favorable intermolecular interactions with the btc linkers. Detailed kinetic studies performed by 1H NMR spectroscopy revealed that the rate of glycylglycine (Gly-Gly) hydrolysis at pD 7.4 and 60 °C was 2.69 × 10-4 s-1 (t1/2 = 0.72 h), which is more than 4 orders of magnitude faster compared to the uncatalyzed reaction. Importantly, MOF-808 can be recycled several times without significantly compromising the catalytic activity. A detailed quantum-chemical study combined with experimental data allowed to unravel the role of the {Zr6O8} core of MOF-808 in accelerating Gly-Gly hydrolysis. A mechanism for the hydrolysis of Gly-Gly by MOF-808 is proposed in which Gly-Gly binds to two Zr(IV) centers of the {Zr6O8} core via the oxygen atom of the amide group and the N-terminus. The activity of MOF-808 was also demonstrated toward the hydrolysis of hen egg white lysozyme, a protein consisting of 129 amino acids. Selective fragmentation of the protein was observed with 55% yield after 25 h under physiological pH.
