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ACS Omega Aug 2023A series of 6-monohalo (Cl, Br, and I) β-cyclodextrin derivatives with various types of methylations were synthesized via a diazotization/nucleophilic displacement...
A series of 6-monohalo (Cl, Br, and I) β-cyclodextrin derivatives with various types of methylations were synthesized via a diazotization/nucleophilic displacement reaction from the corresponding methylated cyclodextrin amines. All four starting compounds (6-amino-6-deoxy derivatives of native β-CD, per-6--methyl-, per-2,3--methyl-, and per-2,3,6--methyl-β-CD) were found to have different reactivities under the same reaction conditions. Unsubstituted and fully per-O-methylated cyclodextrin amines undergo fast transformation, giving lower yields of the monohalogenated product. The selectively methylated cyclodextrin amines react remarkably slower and provide almost complete conversion into the desired monohalogenated compound. A pure product was, in several cases, successfully isolated with simple purification techniques (extraction and precipitation), allowing large-scale preparations. This new method opens the way for preparing poorly investigated monofunctionalized selectively methylated cyclodextrins.
PubMed: 37576619
DOI: 10.1021/acsomega.3c01950 -
Chembiochem : a European Journal of... Aug 2023Aryl diazonium cations are versatile bioconjugation reagents due to their reactivity towards electron-rich aryl residues and secondary amines, but historically their...
Aryl diazonium cations are versatile bioconjugation reagents due to their reactivity towards electron-rich aryl residues and secondary amines, but historically their usage has been hampered by both their short lifespan in aqueous solution and the harsh conditions required to generate them in situ. Triazabutadienes address many of these issues as they are stable enough to endure multiple-step chemical syntheses and can persist for several hours in aqueous solution, yet upon UV-exposure rapidly release aryl diazonium cations under biologically-relevant conditions. This paper describes the synthesis of a novel maleimide-functionalized triazabutadiene suitable for site-selectively installing aryl diazonium cations into proteins at neutral pH; we show reaction with this molecule and a surface-cysteine of a thiol disulfide oxidoreductase. Through photoactivation of the site-selectively installed triazabutadiene motifs, we generate aryl diazonium functionality, which we further derivatize via azo-bond formation to electron-rich aryl species, showcasing the potential utility of this strategy for the generation of photoswitches or protein-drug conjugates.
Topics: Hydrogen-Ion Concentration; Membrane Proteins; Maleimides
PubMed: 37311168
DOI: 10.1002/cbic.202300313 -
Food Chemistry. Molecular Sciences Jul 2023Brown seaweeds () are a rich source of polyphenols (up to 20% dry weight) with a structure based on phloroglucinol (1,3,5-trihydroxybenzene). To-date the determination...
Brown seaweeds () are a rich source of polyphenols (up to 20% dry weight) with a structure based on phloroglucinol (1,3,5-trihydroxybenzene). To-date the determination of total phenolics content (TPC) involves a redox reaction with the Folin-Ciocalteu (FC) reagent. However, side reactions with other reducing substances preclude accurate, direct measurement of TPC. This research reports a novel microplate assay involving a coupling reaction between phloroglucinol with Fast Blue BB (FBBB) diazonium salt, at basic pH, to form a stable tri-azo complex with maximum absorbance at 450 nm. Linear regression correlation values (R) were ≥0.99 with phloroglucinol as standard. Direct quantification of TPCs (phloroglucinol equivalents, PGEs) in crude aqueous and ethanolic extracts from demonstrated that the new FBBB assay is not subject to side-redox interference and provides a more accurate estimate of TPC (1.2-3.9-fold lower than with the FC assay) in a relatively rapid (30 min), cost-effective (0.24€/test) microplate format.
PubMed: 36875799
DOI: 10.1016/j.fochms.2023.100166