72909-34-3Relevant articles and documents
Reaction of Reduced PQQ (PQQH2) and Molecular Oxygen
Itoh, Shinobu,Ohshiro, Yoshiki,Agawa, Toshio
, p. 1911 - 1914 (1986)
Reduced PQQ (PQQH2) is prepared by the reaction of PQQ with thiophenol, 1-benzyl-1,4-dihydronicotinamide (BNAH), sodium dithionite, or sodium borohydride.Oxidation of PQQH2 to PQQ by molecular oxygen in aqueous solutions is investigated kinetically.The oxidation is accelerated gradually with proceeding of the reaction, which may be attributed to the side reaction of PQQH2 and H2O2 produced by the reaction of PQQH2 and O2.As in fact, the yield of H2O2 is found to be 50percent based on PQQH2.Initial rate is first-order in oxygen concentration.The pH-rate profile suggests that an active species in the reaction is PQQH-.Autocatalysis of O2-. and PQQ itself is scarcely detected in this reaction.The mechanism of the oxidation is also discussed.
Studies of Redox Cofactor Pyrroloquinoline Quinone and Its Interaction with Lanthanides(III) and Calcium(II)
Lumpe, Henning,Daumann, Lena J.
, p. 8432 - 8441 (2019)
Recently it was discovered that lanthanides are biologically relevant and found at the centers of many bacterial proteins. Poorly understood, however, is the evolutionary advantage that certain lanthanides might have over calcium at the center of methanol dehydrogenase enzymes bearing redox cofactor PQQ. Here, we present a straightforward method to obtaining clean PQQ from vitamin capsules. Furthermore, we provide full NMR, IR, and UV-vis spectroscopic characterizations of PQQ. We conducted NMR experiments with the stepwise addition of diamagnetic and paramagnetic lanthanides to evaluate the binding to PQQ in solution. This study provides a deeper understanding of PQQ chemistry and its interaction with lanthanides.
Unusual Ionic Bond and Solubility Mechanism of NanPQQ (n = 0-4) Crystals
Ikemoto, Kazuto,Sakamoto, Yuki,Tanaka, Rikako,Ogata, Koji,Matsushita, Nobuyuki,Nakamura, Shinichiro
, p. 4118 - 4123 (2017)
A comparative study of van der Waals and ionic crystals can provide vital information for the medical and food industries. In this work, we investigated the coenzyme pyrroloquinoline quinone (PQQ), which contains three carboxyl groups coupled to imidazole, pyridine, and quinone. Whole-crystal analysis (crystal-ome) was attempted for NanPQQ (n = 0-4) crystals. All deprotonation sites were found to be dependent on pKa except for the Na sites, which cannot be explained by pKa. The Na1PQQ crystal exhibited an unusual ionic bond, forming COOH-Na+ at one of the carboxyl sites in the structure. The difference in the solubility of the van der Waals and ionic crystals was also investigated, with a focus on the dissolution processes of Na0PQQ and Na2PQQ, by combining molecular dynamics simulations with experiments that define the crystal surfaces. This study is the first step toward developing a general rule to link the different types of crystal structures with different dissolution mechanisms and rates.
Characterization of a protein-generated O2 binding pocket in PqqC, a cofactorless oxidase catalyzing the final step in PQQ production
RoseFigura, Jordan M.,Ehringer, Sandra,Schwarzenbacher, Robert,Toyama, Hirohide,Klinman, Judith P.
, p. 1556 - 1566 (2011)
PQQ is an exogenous, tricyclic, quino-cofactor for a number of bacterial dehydrogenases. The final step of PQQ formation is catalyzed by PqqC, a cofactorless oxidase. This study focuses on the activation of molecular oxygen in an enzyme active site without metal or cofactor and has identified a specific oxygen binding and activating pocket in PqqC. The active site variants H154N, Y175F,S, and R179S were studied with the goal of defining the site of O 2 binding and activation. Using apo-glucose dehydrogenase to assay for PQQ production, none of the mutants in this "O2 core" are capable of PQQ/PQQH2 formation. Spectrophotometric assays give insight into the incomplete reactions being catalyzed by these mutants. Active site variants Y175F, H154N, and R179S form a quinoid intermediate (Figure 1) anaerobically. Y175S is capable of proceeding further from quinoid to quinol, whereas Y175F, H154N, and R179S require O2 to produce the quinol species. None of the mutations precludes substrate/product binding or oxygen binding. Assays for the oxidation of PQQH2 to PQQ show that these O2 core mutants are incapable of catalyzing a rate increase over the reaction in buffer, whereas H154N can catalyze the oxidation of PQQH2 to PQQ in the presence of H2O2 as an electron acceptor. Taken together, these data indicate that none of the targeted mutants can react fully to form quinone even in the presence of bound O2. The data indicate a successful separation of oxidative chemistry from O2 binding. The residues H154, Y175, and R179 are proposed to form a core O 2 binding structure that is essential for efficient O2 activation.
Multistep, eight-electron oxidation catalyzed by the cofactorless oxidase, PqqC: Identification of chemical intermediates and their dependence on molecular oxygen
Bonnot, Florence,Iavarone, Anthony T.,Klinman, Judith P.
, p. 4667 - 4675 (2013)
The final step of the biosynthesis of prokaryotic cofactor PQQ is catalyzed by PqqC, a cofactorless oxidase that brings about a ring closure and overall eight-electron oxidation of its substrate. Time-dependent acid quenching and subsequent high-performance liquid chromatography separation and mass spectrometric analyses of reaction mixtures were performed to correlate the structures of intermediates with previously observed UV-visible signatures. The reaction is composed of four stepwise oxidations: three steps use O2 as the two-electron acceptor, and the fourth uses hydrogen peroxide (H 2O2). The chemical nature of the intermediates, the stoichiometry of the reaction, and their dependence on the oxygen concentration indicate that the third oxidation uses the product, H2O2, from the preceding step to produce water. The last oxidation step can also be studied separately and is a reaction between O2 and PQQH2 trapped in the active site. This oxidation is approximately 10 times slower than the reoxidation of PQQH2 in solution. From the order of the four oxidation steps and their sensitivity to O2 concentration, we propose a progressive closure of the active site as the enzyme proceeds through its catalytic cycle.
Preparation method for synthesizing pyrroloquinoline quinone by five-step method
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, (2020/05/01)
The intention discloses a preparation method for synthesizing pyrroloquinoline quinone by a five-step method, and the method comprises the following steps: by using 4-methyl-5-nitro-2-fluoroaniline (2) as a raw material, carrying out cyclization reaction twice to obtain a key intermediate 5-fluoro-1H-pyrrole [2, 3-f] quinoline-2, 7, 9-triformatetrialkyl ester (6); and carrying out hydrolysis reaction, substitution reaction and oxidation reaction to obtain pyrroloquinoline quinone (PQQ, 1). The preparation method has the advantages of greenness, environmental friendliness, easily available rawmaterial, low cost, simple method and suitability for industrial production, and solves the problems of high preparation cost and difficulty in industrial production in the prior art.
PYRROLOQUINOLINE QUINONE MONOSODIUM AND METHOD FOR PRODUCING THE SAME, AND COMPOSITION COMPRISING THE SAME
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Paragraph 0097; 0098-0099, (2019/11/11)
The present invention provides pyrroloquinoline quinone monosodium having a structure represented by the following formula (1).
Pyrroloquinoline quinone synthetic method
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Paragraph 0116-0117, (2018/05/07)
The invention discloses a synthetic method of pyrroloquinoline quinone. The synthetic method comprises the following steps: carrying out alkali treatment on 2-methoxy-5-nitroaniline hydrochloride as a raw material, so as to obtain a compound 1; carrying out formylation on the compound 1 under a catalysis condition of an ionic liquid, so as to obtain a compound 2; adopting sodium borohydride to reduce the compound 2 to obtain a compound 3; carrying out diazotization on the compound 3, and then enabling action between the diazotized compound 3 and HBF4 to obtain a compound 4; enabling reaction of the compound 4 and 2-methylethyl acetoacetate to obtain a compound 5; treating the compound 5 with formic acid to obtain a compound 6; carrying out amid catalysis and exchange with the ionic liquid on the compound 6 to obtain a compound 7; enabling reaction of the compound 7 and 2-oxodimethyl glutaconate to obtain a compound 8; feeding hydrogen chloride to the compound 8 under the action of Cu(OAc)2*2H2O to obtain a compound 9; carrying out basic hydrolysis on the compound 9 to obtain a compound 10. The synthetic method disclosed by the invention is cheap and accessible in raw materials, stable, high in reaction yield, quick in reaction, and easy for product separation, and is environment-friendly as the catalyst can be recycled.
A method for synthesizing pyrroloquinoline quinone (by machine translation)
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Paragraph 0029; 0040; 0049, (2018/08/28)
The invention relates to a synthetic pyrroloquinoline quinone of the method, the method to pyruvic acid ethyl ester as the starting synthetic raw material, preparation pyrroloquinoline quinone. In the synthetic method of the present invention, compound 4 synthesis of compound 5 is the key step in the synthetic route, in the key step 5) in, the invention creative use of hexafluoro antimonate ion liquid, hexafluoro titanate ion liquid, six fluorine niobium acid salt ion liquid such as Lewis acid ionic liquid, the ionic liquid has the function of the reaction medium and the catalyst, thereby improving the response speed and the yield of this step. In addition, the invention preferably use the [BMIm] SbF6 Ionic liquid, [BMIm] SbF6 Ionic liquid and Sc (OTf)3 Can be formed of a higher catalytic activity [Sc (OTf)3 -x ] [SbF6 ], Can make the reaction efficiency is greatly improved, and the obtained reaction product in [BMIm] SbF6 The solubility of the ionic liquid in small, easily precipitated, so as to improve the reaction yield (can be up to 96%). (by machine translation)
4,5-disubstituted-1-hydro-pyrrole(2,3-f)quinoline-2,7,9-tricarboxylate compound and application
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Paragraph 0227; 0228; 0229; 0232; 0233; 0234-0236; 0239-0242, (2017/09/26)
The invention discloses a 4,5-disubstituted-1-hydro-pyrrole(2,3-f)quinoline-2,7,9-tricarboxylate compound and analogues or derivatives thereof. The structure of the compound is shown as a formula I, and the structural formula is as shown in the specification. In the formula, R1 and R4 are respectively and independently selected from the following atoms or groups: hydrogen, linear or branched C1-8 alkyl, deuterated linear or branched C1-8 alkyl, aralkyl or substituted aryl radical; R2 is independently selected from the following atoms or groups: halogen, linear or branched C1-8 alkoxy and deuterated linear or branched C1-8 alkoxy; and R3 is independently selected from the following atoms or groups: linear or branched C1-8 alkoxy and deuterated linear or branched C1-8 alkoxy. The compound can serve as a reaction intermediate for synthesizing PQQ (Pyrroloquinoline Quinone), and the oxidizing agent process adopting CAN in the PQQ synthesis in the conventional patent and literature is replaced. Therefore, the whole process is cheap and high-efficiency.
