655-04-9Relevant academic research and scientific papers
Pyrazine compound and application thereof
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Paragraph 0165; 0167; 0171, (2019/07/04)
The invention discloses a pyrazine compound and application thereof. In particular, the present invention provides a compound represented by the formula (I), wherein the extractant composed of the compound has a high extraction rate for lithium ions, and the organic phase is easy to enrich lithium-7 isotopes, so as to realize the extraction and separation of lithium isotopes.
Selective photocytotoxicity of anthrols on cancer stem-like cells: The effect of quinone methides or reactive oxygen species
Uzelac, Lidija,?kalamera, ?ani,Mlinari?-Majerski, Kata,Basari?, Nikola,Kralj, Marijeta
, p. 558 - 574 (2017/06/23)
Cancer stem cells (CSCs) are a subpopulation of cancer cells that share properties of embryonic stem cells like pluripotency and self-renewal and show increased resistance to chemo- and radiotherapy. Targeting CSC, rather than cancer cells in general, is a novel and promising strategy for cancer treatment. Novel therapeutic approaches, such as photodynamic therapy (PDT) have been investigated. A promising group of phototherapeutic agents are reactive intermediates - quinone methides (QMs). This study describes preparation of QM precursor, 2-hydroxy-3-hydroxymethylanthracene (2) and a detailed photochemical and photobiological investigation on similar anthracene derivatives 3 and 4. Upon photoexcitation with near visible light at λ > 400 nm 1 and 2 give QMs, that were detected by laser flash photolysis and their reactivity with nucleophiles has been demonstrated in the preparative irradiation experiments where the corresponding adducts were isolated and characterized. 3 and 4 cannot undergo photodehydration and deliver QM, but lead to the formation of phenoxyl radical and singlet oxygen, respectively. The activity of 1–4 was tested on a panel of human tumor cell lines, while special attention was devoted to demonstrate their potential selectivity towards the cells with CSC-like properties (HMLEshEcad). Upon the irradiation of cell lines treated with 1–4, an enhancement of antiproliferative activity was demonstrated, but the DNA was not the target molecule. Confocal microscopy revealed that these compounds entered the cell and, upon irradiation, reacted with cellular membranes. Our experiments demonstrated moderate selectivity of 2 and 4 towards CSC-like cells, while necrosis was shown to be a dominant cell death mechanism. Especially interesting was the selectivity of 4 that produced higher levels of ROS in CSC-like cells, which forms the basis for further research on cancer phototherapy, as well as for the elucidation of the underlying mechanism of the observed CSC selectivity based on oxidative stress activation.
Regiospecific oxidation of polycyclic aromatic phenols to quinones by hypervalent iodine reagents
Wu, Anhui,Duan, Yazhen,Xu, Daiwang,Penning, Trevor M.,Harvey, Ronald G.
experimental part, p. 2111 - 2118 (2010/04/26)
The hypervalent iodine reagents o-iodoxybenzoic acid (IBX) and bis(trifluoro-acetoxy)iodobenzene (BTI) are shown to be general reagents for regio-controlled oxidation of polycyclic aromatic phenols (PAPs) to specific isomers (ortho, para, or remote) of polycyclic aromatic quinones (PAQs). The oxidations of a series of PAPs with IBX take place under mild conditions to furnish the corresponding ortho-PAQs. In contrast, oxidations of the same series of PAPs with BTI exhibit variable regiospecificity, affording para-PAQs where structurally feasible and ortho-PAQs or remote PAQ isomers in other cases. The structures of the specific PAQ isomers formed are predictable on the basis of the inherent regioselectivities of the hypervalent iodine reagents in combination with the structural requirements of the phenol precursors. IBX and BTI are recommended as the preferred reagents for regio-controlled oxidation of PAPs to PAQs.
A New Synthesis of ortho-Quinones by Transition-Metal-Mediated Oxygenation of Phenols with tert-Butylhydroperoxide and the Mimoun Oxodiperoxo Molybdenum Complex * Py * HMPT
Krohn, Karsten,Rieger, Hagen,Khanbabaee, Karamali
, p. 2323 - 2330 (2007/10/02)
A specific oxygenation of phenols to ortho-quinones can be effected by a combination of the transition metal complexes Ti(OiPr)4, VO(acac)2, Zr(acac)4, Zr(OnPr)4 and tert-butylhydroperoxide (TBHP) or * Py * HMPT.Naphthols, anthracenols, phenanthrols and donor substituted mononuclear phenols are readily converted into the corresponding 1,2-quinones.Unhindered ortho-naphthoquinones can yield binaphthyls with unreacted starting material by Michael addition. - Key Words: ortho-Quinones / tert-Butyl hydroperoxide / Phenols, oxygenation
Oxidation of Anthracenols and Anthrone to Anthraquinones with Oxygen Mediated by Copper(II) Ion and Imidazole
Iwata, Masaaki,Kuzuhara, Hiroyoshi
, p. 1609 - 1610 (2007/10/02)
The copper(II) chloride-imidazole-ethanol system turned out to oxidize 2-anthracenols to 1,2-anthraquinones and 2-methoxy-9-anthrone to 2-methoxy-9,10-anthraquinone in practical synthetic yield.
Synthesis of the o-Quinones and Dihydro Diols of Polycyclic Aromatic Hydrocarbons from the Corresponding Phenols
Sukumaran, K.B.,Harvey, Ronald G.
, p. 4407 - 4413 (2007/10/02)
Terminal-ring trans-dihydro diol metabolites have been implicated as the ultimate carcinogenic forms of polycyclic aromatic hydrocarbons.Synthesis of these dihydro diols from the related polycyclic phenols in two steps via oxidation to the corresponding o-quinones with either Fremy's salt or phenylseleninic anhydride followed by stereospecific reduction with lithium aluminum hydride is described.The non-K-region quinones and trans-dihydro diols of naphthalene, anthracene, phenanthrene, benzanthracene, benzopyrene, and 7,12-dimethylbenzanthracene are synthesized via this approach.Although poor yields (1-4percent) were previously reported for the reduction of non-K-region quinones, an improved experimental procedure has been developed which affords the trans-dihydro diols free of the isomeric cis-dihydro diols in generally good yields.Major byproducts are the corresponding hydroquinones, previously undetected, and the related tetrahydro diols.The latter are the major products of reduction of the poorly soluble quinones of benzopyrene and benzanthracene and are shown to arise through further reduction of the dihydro diols.Since the tetrahydro diols are convertible to dihydro diols and the hydroquinones are reoxidizable to quinones, good overall conversions of quinones to dihydro diols are attainable. trans-3,4-Dihydroxy-3,4-dihydro-7,12-dimethylbenzanthracene synthesized in these studies is the most potent tumorigenic hydrocarbon metabolite tested to date.
