481-85-6Relevant articles and documents
Maruyama,Arakawa
, p. 1960,1961, 1962, 1966 (1974)
Detection and quantification of vitamin K1 quinol in leaf tissues
Oostende, Chloe van,Widhalm, Joshua R.,Basset, Gilles J.C.
, p. 2457 - 2462 (2008)
Phylloquinone (2-methyl-3-phytyl-1,4-naphthoquinone; vitamin K1) is vital to plants. It is responsible for the one-electron transfer at the A1 site of photosystem I, a process that involves turnover between the quinone and semi-quinone forms of phylloquinone. Using HPLC coupled with fluorometric detection to analyze Arabidopsis leaf extracts, we detected a third redox form of phylloquinone corresponding to its fully reduced - quinol-naphthoquinone ring (PhQH2). A method was developed to quantify PhQH2 and its corresponding oxidized quinone (PhQ) counterpart in a single HPLC run. PhQH2 was found in leaves of all dicotyledonous and monocotyledonous species tested, but not in fruits or in tubers. Its level correlated with that of PhQ, and represented 5-10% of total leaf phylloquinone. Analysis of purified pea chloroplasts showed that these organelles accounted for the bulk of PhQH2. The respective pool sizes of PhQH2 and PhQ were remarkably stable throughout the development of Arabidopsis green leaves. On the other hand, in Arabidopsis and tomato senescing leaves, PhQH2 was found to increase at the expense of PhQ, and represented 25-35% of the total pool of phylloquinone. Arabidopsis leaves exposed to light contained lower level of PhQH2 than those kept in the dark. These data indicate that PhQH2 does not originate from the photochemical reduction of PhQ, and point to a hitherto unsuspected function of phylloquinone in plants. The putative origin of PhQH2 and its recycling into PhQ are discussed.
Reduction of quinones by NADH catalyzed by organoiridium complexes
Liu, Zhe,Deeth, Robert J.,Butler, Jennifer S.,Habtemariam, Abraha,Newton, Mark E.,Sadler, Peter J.
, p. 4194 - 4197 (2013)
One electron at a time: Half-sandwich organometallic cyclopentadienyl- IrIII complexes containing N,N-chelated ligands can catalyze the reduction of quinones (Q), such as vitaminK3, to semiquinones (Q .-) by coenzyme NADH (see picture). DFT calculations suggest that the mechanism involves hydride transfer followed by two one-electron transfers and the unusual IrII oxidation state as a key transient intermediate. Copyright
Synthesis of novel vitamin K derivatives with alkylated phenyl groups introduced at the ω-terminal side chain and evaluation of their neural differentiation activities
Sakane, Rie,Kimura, Kimito,Hirota, Yoshihisa,Ishizawa, Michiyasu,Takagi, Yuta,Wada, Akimori,Kuwahara, Shigefumi,Makishima, Makoto,Suhara, Yoshitomo
, p. 4881 - 4884 (2017)
Vitamin K is an essential cofactor of γ-glutamylcarboxylase as related to blood coagulation and bone formation. Menaquinone-4, one of the vitamin K homologues, is biosynthesized in the body and has various biological activities such as being a ligand for steroid and xenobiotic receptors, protection of neuronal cells from oxidative stress, and so on. From this background, we focused on the role of menaquinone in the differentiation activity of progenitor cells into neuronal cells and we synthesized novel vitamin K derivatives with modification of the ω-terminal side chain. We report here new vitamin K analogues, which introduced an alkylated phenyl group at the ω-terminal side chain. These compounds exhibited potent differentiation activity as compared to control.
NAPHTHOQUINONE-BASED CHALCONE DERIVATIVES AND USES THEREOF
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Paragraph 00175, (2021/09/04)
The present disclosure provides compounds of formula 1 to inhibit or prevent mitochondrial dysfunction by augmenting mitochondrial function. Mitochondrial dysfunction is the hallmark of a wide range of diseases and disorders. Mitochondria are a promising therapeutic target for the detection, prevention and treatment of various human diseases such as cancer, neurodegenerative diseases, ischemia-reperfusion injury, diabetes and obesity.
Stereoselective [4+2] cycloaddition of singlet oxygen to naphthalenes controlled by carbohydrates
Bauch, Marcel,Fudickar, Werner,Linker, Torsten
, (2021/06/12)
Stereoselective reactions of singlet oxygen are of current interest. Since enantioselective photooxygenations have not been realized efficiently, auxiliary control is an attractive alternative. However, the obtained peroxides are often too labile for isolation or further transformations into enantiomerically pure products. Herein, we describe the oxidation of naphthalenes by singlet oxygen, where the face selectivity is controlled by carbohydrates for the first time. The synthesis of the precursors is easily achieved starting from naphthoquinone and a protected glucose derivative in only two steps. Photooxygenations proceed smoothly at low temperature, and we detected the corresponding endoperoxides as sole products by NMR. They are labile and can thermally react back to the parent naphthalenes and singlet oxygen. However, we could isolate and characterize two enantiomerically pure peroxides, which are sufficiently stable at room temperature. An interesting influence of substituents on the stereoselectivities of the photooxygenations has been found, ranging from 51:49 to up to 91:9 dr (diastereomeric ratio). We explain this by a hindered rotation of the carbohydrate substituents, substantiated by a combination of NOESY measurements and theoretical calculations. Finally, we could transfer the chiral information from a pure endoperoxide to an epoxide, which was isolated after cleavage of the sugar chiral auxiliary in enantiomerically pure form.
Bioinspired Photoredox Benzylation of Quinones
Donzel, Maxime,Elhabiri, Mourad,Davioud-Charvet, Elisabeth
supporting information, p. 10055 - 10066 (2021/07/31)
3-Benzylmenadiones were obtained in good yield by using a blue-light-induced photoredox process in the presence of Fe(III), oxygen, and γ-terpinene acting as a hydrogen-atom transfer agent. This methodology is compatible with a wide variety of diversely substituted 1,4-naphthoquinones as well as various cheap, readily available benzyl bromides with excellent functional group tolerance. The benzylation mechanism was investigated and supports a three-step radical cascade with the key involvement of the photogenerated superoxide anion radical.
