- Arylglyoxal oximes as putative C-nucleophiles in eliminative nucleophilic substitution process
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Reaction of arylglyoxal oximes ArCOCH=NOH (Ar = 4-MeOC6H4, Ph) with 5-arylfurazanopyrazines proceeds as vicarious nucleophilic substitution of hydrogen in pyrazine ring with the elimination of hyponitrous acid, affording 5-(aroylmethylidene)-6-aryl-4H-furazano[3,4-b]pyrazines. Structure of the product was confirmed by X-ray diffraction.
- Tsyganov, Dmitry V.,Samet, Alexander V.,Dorovatovskii, Pavel V.,Khrustalev, Victor N.,Semenov, Victor V.
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p. 296 - 298
(2019/06/13)
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- Copper-catalyzed direct amination of 1,2,3-triazole N-oxides by C-H activation and C-N coupling
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An efficient approach for the synthesis of 4-amino-2-aryl- 1,2,3-triazole derivatives has been developed through the copper-catalyzed direct C-H amination of 2-aryl-1,2,3-triazole N-oxides under mild reaction conditions. Various amines, including primary and secondary aliphatic and aromatic amines, can be employed as effective coupling partners. The general performance of our method was also demonstrated by the oxidative amination of thiazole and imidazole N-oxides.
- Zhu, Jiayi,Kong, Yubo,Lin, Feng,Wang, Baoshuang,Chen, Zhengwang,Liu, Liangxian
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supporting information
p. 1507 - 1515
(2015/03/04)
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- Synthesis and biological activities of 2,4-diaminopteridine derivatives
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Substituted 2,4-diaminopteridine derivatives 10a-10l were prepared in moderate to good yield. Their structures were confirmed by 1H-NMR and MS spectroscopy, as well as by elemental analysis. Their inhibitory properties against inducible nitric oxide synthase (iNOS) were evaluated in vitro. Biological tests indicated that compound 10a, 10d, 10e, 10h, 10i, and 10l showed potent inhibitory activities similar to that of methotrexate (MTX), while the activities of compound 10b, 10c, 10f, 10g, 10j, and 10k are stronger than MTX. Two compounds, i. e., 10b (IC50 = 18.85 μM) and 10i (IC 50 = 24.08 μM) were further studied for their effect on septic shock in rats and immunologically liver injured mice (in vivo). The results demonstrated that 10b and 10i had the capacity to increase the blood pressure in septic shock and showed notable protective activities on immunological hepatic injury.
- Ma, Fei,Lue, Gang,Zhou, Wei-Fen,Wang, Qiu-Juan,Zhang, Yi-Hua,Yao, Qi-Zheng
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experimental part
p. 274 - 280
(2009/09/06)
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- One-pot synthesis of 3-amino-4-aryl- and 3-amino-4-hetarylfurazans
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A "one pot" method for the synthesis of 3-amino-4-aryl- and 3-amino-4-hetarylfurazans from β-aryl- and 4-β-hetaryl-β-oxo acid esters was developed.
- Sheremetev
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p. 1057 - 1059
(2007/10/03)
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- A remarkably simple α-oximation of ketones to 1,2-dione monooximes using the chlorotrimethylsilane-isoamyl nitrite combination
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Ketones undergo α-oximation by NOCl formed in situ from Me3SiCl and isoamyl nitrite, either in solution or under solvent-free conditions, to produce 1,2-dione monooximes in excellent yields. The oximation is regiospecific in appropriate cases.
- Mohammed, Abdulkarim H.A.,Nagendrappa, Gopalpur
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p. 2753 - 2755
(2007/10/03)
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- Low-temperature photooxygenation of coelenterate luciferin analog synthesis and proof of 1,2-dioxetanone as luminescence intermediate
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Coelenterate luciferin analog having bulky tert-butyl group at the 2-position was suitable for studies on chemiluminescence under various conditions. Photooxygenation of the analog(s) at low temperature (-78°C) afforded luminous intermediates which were proved as peroxides by reduction with PPh3 with resultant loss of luminescence ability. In order to clarify these structures of accumulated luminous intermediates by means of 13C NMR, three 13C enriched analogs were synthesized at the 2, 3 and 5 positions of 3,7-dihydroimidazo[1,2-a]pyrazin-3-one skeleton in 99% enrichment with site-specificity. These 13C-enriched coelenterate luciferin analogs were photooxygenated at -78°C to form two peroxidic products as luminescent intermediates. Structures of these unstable intermediates were deduced by means of 13C NMR spectra at low temperature using substrates enriched at three sites by 13C. Photooxygenation in a mixture of CF3CD2OD and CD3OD as highly protic solvents afforded the dioxetanone and 2-hydroperoxide. These two peroxides emitted light independently at different temperatures either at 400 nm (neutral species) and/or 475 nm (anionic species) after diluting to 10-5 M in diglyme (DGM) containing acid or base.
- Usami, Ken,Isobe, Minoru
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p. 12061 - 12090
(2007/10/03)
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- The Oxidation of 6- and 7-Aryl-4(3H)-pteridinones by Immobilized Arthrobacter M-4 Cells Containing Xanthine Oxidase
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The preparation of 6- and 7-(pX-phenyl)-4(3H)-pteridinones (X = H, CH3, OCH3) is described.The oxidation of these compounds by (immobilized) Arthrobacter M-4 cells containing xanthine oxidase has been studied.The oxidation monitored by uv spectroscopy usually goes fast, except for 7-(pX-phenyl)-4(3H)-pteridinones (X = CH3, OCH3), which are slowly oxidized.With bacterial cells immobilized in gelatine crosslinked with glutaraldehyde small laboratory-scale oxidations were carried out.Based on spectral data the products of the oxidation reactions are 6- and 7-aryllumazines.
- Meester, Johan W. G. De,Plas, Henk C. van der,Middelhoven, Wouter J.
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p. 441 - 451
(2007/10/02)
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