Photochromism of (E)-4-phenyl-1-(pyridine-2-ylmethylene)semicarbazide

Lin, Li-Rong; Fan, Weizhen; Chen, Shui; Ma, Jie; Hu, Wangxia; Lin, Yuan; Zhang, Hui; Huang, Rong‐Bin

doi:10.1039/c2nj40468k

Cited by 10 publications

(4 citation statements)

References 28 publications

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“…Working sample, used for the measurement of UV-Vis spectra, was prepared in such a way to obtain V(DMSO)/V(H 2 O) mixed solvents ratio of 4/1, 25 and solution was UV irradiated continuously at a wavelength of absorption maximum. 26 Concentration of the hydrazones in the obtained solution was 5×10 -5 mol L -1 .…”

Section: Samples Preparation For Uv-measurementsmentioning

confidence: 99%

“…Analogous phenomenon was described in the literature for (E)-4-phenyl-1-(pyr-idin-2-ylmethylene)semicarbazide which exhibited photochromism in both solution and solid state. 26 2-Benzoylpyridine semicarbazone analogues of compound 4, can have the (E)- 31 and (Z)-configuration 32 (Fig. S-6).…”

Section: Chemistrymentioning

confidence: 99%

“…Furthermore, the position of the pyridine nitrogen atom with respect to the C=N double bond is important too, and the ortho-nitrogen position leads to the most photosensitivne sequence. 26,36 For structurally related aroylhydrazones, it has been reported that (E)-isomers prevail in non-aqueous media, while water induces changes in conformation leading to the formation of (Z)-isomers, 37 and formation of hydrated molecules. 25 The (E)/(Z) isomerisation of hydrazones could be noticed in UV spectra since (E)-and (Z)-isomers have different absorption maxima.…”

Section: Structural Investigation Of 4 In Dimethyl Sulphoxide/water Mmentioning

confidence: 99%

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Synthesis, antioxidant and antimicrobial activity of carbohydrazones

Božić¹,

Filipović

Novaković

et al. 2017

J Serb Chem Soc

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Fourteen mono-and bis-carbohydrazone ligands have been synthesized and characterized. Antioxidant activity of the substances was investigated together with possible (E)/(Z) isomerization, and explained on the most active antioxidant compound 4 in various dimethyl sulphoxide-water mixtures. The addition of water to the system was involved in the formation of hydrated molecules which was confirmed in NMR after the addition of D 2 O. The ligands were tested in vitro against Gram-positive and Gram-negative bacteria and fungi, and their activity was discussed in relation to the structure of investigated carbohydrazone.

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Section: Samples Preparation For Uv-measurementsmentioning

confidence: 99%

Section: Chemistrymentioning

confidence: 99%

Section: Structural Investigation Of 4 In Dimethyl Sulphoxide/water Mmentioning

confidence: 99%

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Synthesis, antioxidant and antimicrobial activity of carbohydrazones

Božić¹,

Filipović

Novaković

et al. 2017

J Serb Chem Soc

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“…Condensation of these semicarbazides with 4-bromobenzaldehyde proceeded well in all examples, and the desired products ( 1 , 9a – c , and 10 ) were obtained pure by recrystallization (Scheme ). The stereochemistry of the semicarbazone double bond is assigned as E based on analogy with known benzaldehyde semicarbazone structures. − …”

mentioning

confidence: 99%

Structure–Activity Relationship of Semicarbazone EGA Furnishes Photoaffinity Inhibitors of Anthrax Toxin Cellular Entry

Jung

Chamberlain

et al. 2014

ACS Med. Chem. Lett.

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EGA, 1, prevents the entry of multiple viruses and bacterial toxins into mammalian cells by inhibiting vesicular trafficking. The cellular target of 1 is unknown, and a structure− activity relationship study was conducted in order to develop a strategy for target identification. A compound with midnanomolar potency was identified (2), and three photoaffinity labels were synthesized (3−5). For this series, the expected photochemistry of the phenyl azide moiety is a more important factor than the IC 50 of the photoprobe in obtaining a successful photolabeling event. While 3 was the most effective reversible inhibitor of the series, it provided no protection to cells against anthrax lethal toxin (LT) following UV irradiation. Conversely, 5, which possessed weak bioactivity in the standard assay, conferred robust irreversible protection vs LT to cells upon UV photolysis. KEYWORDS: Photoaffinity labeling, semicarbazone, aryl azide, anthrax lethal toxin, endosomal trafficking A common mechanism by which viruses and bacterial toxins enter host cells involves trafficking from an early to a late endosome followed by release into the cytoplasm as triggered by endosomal acidification. 1−3 Inhibition of this process represents a host-targeted strategy for the development of broad-spectrum antiviral and antibacterial drugs. Recently, EGA, N 1 -(4-bromobenzylidene)-N 4 -(2,6-dimethylphenyl)-semicarbazone, 1, was identified from a high-throughput phenotypic screen to protect cells from anthrax lethal toxin (LT). 4 Further investigations showed that 1 protected cells from multiple viruses and bacterial toxins that rely on pHdependent endosomal trafficking to enter cells. Although the details of the biochemical mechanism have been studied, the cellular target(s) remain unknown. We have conducted a structure−activity relationship (SAR) study with the goal of improving the potency of 1 and developing a strategy for photoaffinity labeling and identification of the involved proteins.A series of derivatives of 1 were synthesized and tested, revealing precise requirements for activity in a tight and relatively flat structure−activity landscape. The 2,6-dimethyl substitution in the N 4 -ring as well as an unaltered semicarbazone core were shown to be optimal for activity while certain modifications to the N 1 -phenyl ring were tolerated. From the SAR, a compound more potent than the original hit was generated, namely the N 1 -2-fluoro-4-bromophenyl analogue (IC 50 = 0.4 μM), 2. In addition, three photoaffinity probes, 3−5, two of which possess low micromolar activity, were designed and synthesized. Our key finding is that the expected photochemistry of the phenyl azide moiety is a more important factor than the IC 50 of the photoprobe in achieving successful photolabeling. While 3 was the most potent inhibitor of intoxication by LT in the standard assay, it did not provide protection to the cells upon UV photolysis. Conversely 5, which possesses two fluorine atoms ortho to the azido function, was a poor inhibitor in the stand...

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