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Crystallization and Structural Linkages of COFs
Published in Atsushi Nagai, Covalent Organic Frameworks, 2019
Like the reaction of imine-linked COFs, the reaction of benzaldehyde and hydrazide groups could yield hydrazine-linked COFs (Fig. 2.19). Hydrazone-linked COFs represent good chemical stability relative to imine-linked ones because of the hydrogen-bonding interaction between the oxygen atom in the alkoxyl chain and the hydrogens in amide (–CONH–) units. However, the functional monomers available for the condensation of hydrazone-based COFs are limited. Recently, the first hydrazone-based COFs were developed by the condensation reaction of a difunctional acylhydrazide (2,5-diethoxyterephthalohydraide) and trifunctional aldehydes (1,3,5-triformylbenzene or 1,3,5-tris(4-formylphenyl) benzene) to provide two crystalline mesoporous COFs, COF-42 and COF-43 [63]. Synthesis of hydrazone-linked COFs (COF-42, COF-43, and TFPT COF).
Conjugates of Magnetic Nanoparticle-Enzyme for Bioremediation
Published in Matthew Laudon, Bart Romanowicz, 2007 Cleantech Conference and Trade Show Cleantech 2007, 2019
You Qiang, Amit Sharma, Andrzej Paszczynski, Daniel Meyer
The enzymes were covalently linked with nanoparticles by reacting them separately with amino-silane or peptide coated nanoparticles. After the modifications the MNP’s were purified of excess reagent. The hydrazine/hydrazide-modified MNP’s were reacted with the aldehyde-modified molecule to yield the desired MNP-E conjugates (Fig. 2). Both reaction mixtures (enzyme + SANH and MNP’s + SFB) were incubated for 3 hours at room temperature with no shaking in buffer (pH=7.3). The concentration of SFB and SANH were in 10 molar excess of protein or MNP’s. After activation the excess of the heterobifunctional coupling agent and the buffer replacement (to the conjugation buffer, pH=4.7) was performed in single chromatographic step using a Sephadex G25, PD 10 column.
The Art of Bioconjugation: Functionalization of VNPs
Published in Nicole F Steinmetz, Marianne Manchester, Viral Nanoparticles, 2019
Nicole F Steinmetz, Marianne Manchester
Some viruses, such as the archaeal virus Sulfolobus islandicus rod-shaped virus 2 (SIRV2), are glycosylated, allowing chemical modification using carbohydrate-selective chemistries (Steinmetz et al., 2008a) (see also Section 4.3.5). In order to make use of carbohydrates, the hydroxyls must be converted into aldehydes. This is typically achieved under mild oxidation conditions using the reagent sodium meta-periodate. The aldehyde groups are reactive toward hydrazide conjugates and undergo a facile coupling reaction that results in the formation of a covalent hydrazone linkage (Fig. 4.5) (Aslam & Dent, 1999; Hermanson, 1996). Coupling reaction between an oxidized carbohydrate and a hydrazide derivative. Figure provided by courtesy of Vu Hong (TSRI, La Jolla, CA, USA).
Synthesis and liquid crystalline behavior of hydrazide-functionalized triphenylenedicarboxyimides
Published in Liquid Crystals, 2022
Yu Du, Cai-Li Zhao, Sheng-Yuan Fan, Wen-Hao Yu, Shi-Kai Xiang, Ke-Qing Zhao, Chun Feng, Bi-Qin Wang
Each of these hydrazide-functionalised TDIs was designed to contain a hydrazide group to have the possibility of forming intermolecular hydrogen bonds. It was anticipated that the stability of the mesophase can be achieved by synergistic effects of π–π stacking, hydrogen bonding and van der Waals forces. Preparation of these hydrazides was achieved in a straightforward manner through condensation reactions between triphenylene dicarboxylic acid anhydride and hydrazide (Scheme 1). The key precursor TPC10anhydride were synthesised from the corresponding triphenylene 2,3-dicarboxylic esters as previously reported from our laboratory [38]. The hydrazide precursors were obtained by reaction of benzoic acid methyl ester with hydrazine hydrate. The final condensation reaction occurred at 130°C in toluene giving seven hydrazides in high yields. The detailed synthetic procedures and compound characterisation data for the target hydrazides are provided in the Experimental section. For comparison, analogue TDI-pC6H4Br having the similar structure as TDI-NHCO-pC6H4Br but lacking hydrogen bonding group was also prepared from triphenylene 2,3-dicarboxylic ester and 4-bromoaniline according to the literature procedure [37,39].
L-proline catalyzed green synthesis and anticancer evaluation of novel bioactive benzil bis-hydrazones under grinding technique
Published in Green Chemistry Letters and Reviews, 2021
Abdelwahed R. Sayed, Sobhi M. Gomha, Hany M. Abd El-lateef, Tariq Z. Abolibda
Cyanoacetic acid hydrazide is a powerful and convenient precursor for the synthesis of a wide range of heterocyclic compounds. The molecule's β-functional nitrile (34–37) is a favorable unit for addition, accompanied by cyclization or cycloaddition, of various reagents supplying one or more heteroatoms with heterocyclic compounds of different ring sizes that are of interest as antibacterial agents, herbicides, pharmaceuticals (38–40) and as dyes (41).