- An emissive and pH switchable hydrazone-based hydrogel
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A serendipitous discovery has led to a new hydrazone-based low molecular weight fluorescent super-hydrogelator. The gelation and emission properties can be switched "ON" and "OFF" using pH, enabling the sensing of biogenic amines emanating from spoiled cod.
- Qian, Hai,Aprahamian, Ivan
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- Copper-Catalyzed Transformation of Hydrazones into Halogenated Azabutadienes, Versatile Building Blocks for Organic Synthesis
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A one-step copper-catalyzed reaction of aldehyde-derived N-substituted hydrazones with CCl4 resulted in efficient synthesis of 4,4-dichloro-1,2-diazabuta-1,3-dienes. It was proven that this C-C bond-forming cascade reaction operates via an addition of trichloromethyl radical to the C=N bond of hydrazone followed by a base-induced elimination of HCl. The reaction was found to be very general, as diverse hydrazones possessing various aromatic groups at N-site, as well as aromatic, aliphatic, and heterocyclic substituents at C-site, are capable partners for coupling with a wide range of polyhalogenated compounds (CCl3Br, CBr4, CCl3CN, CCl3COOEt, CCl3CF3, CBr3CF3) to produce a family of functionalized 1,2-diazabuta-1,3-dienes. It was demonstrated that the prepared heterodienes are highly versatile building blocks for straightforward assembly of various valuable acyclic and heterocyclic molecules.
- Nenajdenko, Valentine G.,Shastin, Alexey V.,Gorbachev, Vladimir M.,Shorunov, Sergey V.,Muzalevskiy, Vasiliy M.,Lukianova, Anna I.,Dorovatovskii, Pavel V.,Khrustalev, Victor N.
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- Hydrazone Photoswitches for Structural Modulation of Short Peptides
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Molecules that undergo light-driven structural transformations constitute the core components in photoswitchable molecular systems and materials. Among various families of photoswitches, photochromic hydrazones have recently emerged as a novel class of photoswitches with superb properties, such as high photochemical conversion, spectral tunability, thermal stability, and fatigue resistance. Hydrazone photoswitches have been adopted in various adaptive materials at different length scales, however, their utilization for modulating biomolecules still has not been explored. Herein, we present new hydrazone switches that can photomodulate the structures of short peptides. Systematic investigation on a set of hydrazone derivatives revealed that installation of the amide group does not significantly alter the photoswitching behaviors. Importantly, a hydrazone switch comprising an upper phenyl ring and a lower quinolinyl ring was effective for structural control of peptides. We anticipate that this work, as a new milestone in the research of hydrazone switches, will open a new avenue for structural and functional control of biomolecules.
- Ahn, Sangdoo,Jeong, Myeongsu,Kwon, Sunbum,Lee, Kwonjung,Park, Jiyoon,Pramanik, Susnata,Seo, Yejin
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supporting information
(2022/02/05)
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- Photochromic Hydrazone Switches with Extremely Long Thermal Half-Lives
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A family of easily accessible light-activated hydrazone switches has been developed having thermal half-lives of up to 2700 years! Structure-property analysis shows that replacing the rotor pyridyl group of our typical hydrazone switch with a phenyl one leads to the long-lived negative photochromic compounds. The switching properties of the hydrazones in both toluene and DMSO were assessed offering insights into the kinetics and thermodynamics of the switching process.
- Qian, Hai,Pramanik, Susnata,Aprahamian, Ivan
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supporting information
p. 9140 - 9143
(2017/07/22)
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- Oxidation and rearrangement of 5-substituted 5- ethoxycarbonyl[1,2,4]triazolidine-3-thiones
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The reaction of ethyl 2-(phenylhydrazono)alkanoates (1) with potassium thiocyanate in acetic acid affords 5-ethoxycarbonyl-substituted [1,2,4]triazolidine-3-thiones (3). Oxidation (KMnO4) converts 3 into 1- ethoxycarbonyl-2,3-dihydro-1H-[1,2,4]
- Schantl, Joachim G.,Lang, Sergius,Wurst, Klaus
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p. 251 - 258
(2007/10/03)
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- Oxidation of hydrazones by hypervalent organoiodine reagents: Regeneration of the carbonyl group and facile syntheses of α-acetoxy and α-alkoxy azo compounds
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Various hydrazone derivatives of α-keto esters were prepared. The carbonyl group was readily regenerated in high yield from phenylhydrazones through oxidative hydrolysis using hypervalent organoiodine(III) reagents either bis(trifluoroacetoxy)-iodobenzene (BTIB) in aqueous acetonitrile or hydroxy(tosyloxy)iodobenzene (HTIB) in chloroform. α-Acotxy phenyl- or methylazo compounds were readily synthesized by oxidation of the corresponding hydrazones with iodobenzene diacetate (IBDA) in dichloromethane or acetic acid. α-Methoxy phenyl- or methylazo compounds were also prepared by oxidation of the hydrazones in methanol. The mechanisms of the oxidation reactions are discussed.
- Barton, Derek H. R.,Jaszberenyi, Joseph Cs.,Liu, Wansheng,Shinada, Tetsuro
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p. 14673 - 14688
(2007/10/03)
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- REARRANGEMENTS OF AROMATIC CARBONYL ARYLHYDRAZONES OF BENZENE, NAPHTHALENE, AND AZULENE
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Aromatic carbonyl arylhydrazones have been shown to undergo two kinds of rearrangement in polyphosphoric acid both involving nitrogen-nitrogen bond cleavage.The first proceeds via insertion of the imine portion in the position ortho to the second nitrogen atom to give o-phenylenediamine intermediates: their evolution depends on the nature of the starting substrate.This reaction has been employed for synthesizing the quinoxalines (5) and the phenanthridines (11), and was demonstrated to be intramolecular.The second reaction path is a sigmatropic rearrangment exclusive to electron-rich aromatic carbonyl hydrazones.
- Benincori, Tiziana,Pagani, Silvia Bradamante,Fusco, Raffaello,Sannicolo, Franco
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p. 2721 - 2728
(2007/10/02)
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- Reactions of Aromatic Diazonium Salts with Diethyl Sodiomalonate
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Benzenediazonium chloride and m-toluenediazonium chloride react with sodium salt of diethyl malonate in aqueous ethanol to give the coupling products (I and V) as the major products, along with the products (II, III, IV, VI) apparently derived from the coupling products.All the products obtained have been fully characterised by IR and PMR data.
- Ahmad, Mesbah U.,Islam, M. D. Rabiul,Hossain, Mosharraf M.,Arjumannessa, Laila
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p. 523 - 524
(2007/10/02)
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