One‐Pot Hydroacetylation of Menadione (Vitamin K<sub>3</sub>) to Menadiol Diacetate (Vitamin K<sub>4</sub>) by Heterogeneous Catalysis

Menaquinones (naphthoquinones, MK) are isoprenoids that play key roles in the respiratory electron transport system of some prokaryotes by shuttling electrons between membrane-bound protein complexes acting as electron acceptors and donors. Menaquinone-2 (MK-2), a truncated MK, was synthesized, and the studies presented herein characterize the conformational and chemical properties of the hydrophobic MK-2 molecule. Using 2D NMR spectroscopy, we established for the first time that MK-2 has a folded conformation defined by the isoprenyl side-chain folding back over the napthoquinone in a U-shape, which depends on the specific environmental conditions found in different solvents. We used molecular mechanics to illustrate conformations found by the NMR experiments. The measured redox potentials of MK-2 differed in three organic solvents, where MK-2 was most easily reduced in DMSO, which may suggest a combination of solvent effect (presumably in part because of differences in dielectric constants) and/or conformational differences of MK-2 in different organic solvents. Furthermore, MK-2 was found to associate with the interface of model membranes represented by Langmuir phospholipid monolayers and Aerosol-OT (AOT) reverse micelles. MK-2 adopts a slightly different U-shaped conformation within reverse micelles compared to within solution, which is in sharp contrast to the extended conformations illustrated in literature for MKs.

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“…Menadiol formation is indicative by 1 H NMR (CDCl 3 ) by the presence of a peak at 6.64 ppm and is consistent with literature. 93 …”

Section: Methodsmentioning

confidence: 99%

A Synthetic Isoprenoid Lipoquinone, Menaquinone-2, Adopts a Folded Conformation in Solution and at a Model Membrane Interface

et al. 2017

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“…Vitamin K 1–5 (VK 1–5 ) are compounds with structures similar to anthraquinone derivatives containing aromatic rings and ketone structure, except Vitamin K 4 (VK 4 ) and vitamin K 5 (VK 5 ), which are the reduced ketone derivatives of vitamin K 3 (VK 3 ). − Vitamin K 1 (VK 1 ) is a natural vitamin in green leafy vegetables with a low toxicity and has been used as an oral nutrient supplementary or injection to prevent bleeding caused by vitamin K deficiency . Vitamin K 2 (VK 2 ) is also a natural product in fermented food or animal food and functions similarly as VK 1 in the human body .…”

Section: Introductionmentioning

confidence: 99%

Photoactivities of Vitamin K Derivatives and Potential Applications as Daylight-Activated Antimicrobial Agents

Zhang

Sun

2019

ACS Sustainable Chem. Eng.

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Photoactivities of four natural or naturalderivatized vitamin K (VK) species were investigated by using a combination of theoretical computational modeling, prediction, and specially designed experimental tests. The results revealed that these VK compounds are photoactive in the generation of reactive oxygen species of hydroxyl radicals and singlet oxygen under daylight, UVA, and UVB irradiations. Two possible photoreaction paths exist in an environment of good or poor hydrogen donors. Vitamin K 3 (VK 3 ), as an aromatic naphthoquinone compound, was predicted and demonstrated as the most effective photoactive agent under a broad range of UV−vis wavelengths and in production of both hydroxyl radicals and singlet oxygen. VK 1 and VK 2 are less active than VK 3 due to the existence of double bonds in their side chains of naphthoquinone. VK 4 is different in photoactivity due to the loss of an aromatic ketone structure. As an example, VK 3 was tested against Gram-negative Escherichia coli and Gram-positive Listeria innocua under daylight irradiation and exhibited complete kill of Escherichia coli (six log reduction in 60 min of daylight exposure) and Listeria innocua (five log reduction in 90 min of daylight exposure). In addition, VK 3 retained its high bactericidal efficacy toward both Escherichia coli and Listeria innocua after seven times of repeated daylight exposures, indicating excellent reusability as a green biocide. This work provides insight into the development of green and sustainable photoinduced antimicrobial materials for biomedical and food safety applications.

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“…Dobrinescu and co-workers studied, besides acetylation reactions, the hydroacetylation of menadione for the synthesis of diacetylated menadiol derivatives through heterogeneous catalysis [ 121 ]. The first methodology involved the reduction of menadione ( 10 ) to menadiol ( 14 ), with sodium dithionite, followed by hydroacetylation of 14 with acetic anhydride, using nanoscopic acidic hydroxylated metal fluorides MF n - x (OH) x (M = Mg, Al; n = 2, 3; x < 0.1) as catalysts.…”

Section: Reviewmentioning

confidence: 99%

Menadione: a platform and a target to valuable compounds synthesis

Souza¹,

Ribeiro²,

Costa³

et al. 2022

Beilstein J. Org. Chem.

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Naphthoquinones are important natural or synthetic compounds belonging to the general class of quinones. Many compounds in this class have become drugs that are on the pharmaceutical market for the treatment of various diseases. A special naphthoquinone derivative is menadione, a synthetic naphthoquinone belonging to the vitamin K group. This compound can be synthesized by different methods and it has a broad range of biological and synthetic applications, which will be highlighted in this review.

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One‐Pot Hydroacetylation of Menadione (Vitamin K₃) to Menadiol Diacetate (Vitamin K₄) by Heterogeneous Catalysis

Cited by 12 publications

References 33 publications

A Synthetic Isoprenoid Lipoquinone, Menaquinone-2, Adopts a Folded Conformation in Solution and at a Model Membrane Interface

A Synthetic Isoprenoid Lipoquinone, Menaquinone-2, Adopts a Folded Conformation in Solution and at a Model Membrane Interface

Photoactivities of Vitamin K Derivatives and Potential Applications as Daylight-Activated Antimicrobial Agents

Menadione: a platform and a target to valuable compounds synthesis

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One‐Pot Hydroacetylation of Menadione (Vitamin K3) to Menadiol Diacetate (Vitamin K4) by Heterogeneous Catalysis

Cited by 12 publications

References 33 publications

A Synthetic Isoprenoid Lipoquinone, Menaquinone-2, Adopts a Folded Conformation in Solution and at a Model Membrane Interface

A Synthetic Isoprenoid Lipoquinone, Menaquinone-2, Adopts a Folded Conformation in Solution and at a Model Membrane Interface

Photoactivities of Vitamin K Derivatives and Potential Applications as Daylight-Activated Antimicrobial Agents

Menadione: a platform and a target to valuable compounds synthesis

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One‐Pot Hydroacetylation of Menadione (Vitamin K₃) to Menadiol Diacetate (Vitamin K₄) by Heterogeneous Catalysis