The Synthesis of Novel Isoindoline Nitroxides Bearing Water‐Solubilising Functionality

Abstract

A range of novel tetramethyl‐ and tetraethylisoindolinenitroxides, possessing aryl‐linked carboxylic acids, amines, alcohols and phosphonic acids were prepared. Notably, the chemistry established for the aromatic dibromination of the tetramethylisoindolines was not easily transferred to the corresponding tetraethylisoindoline system. Instead, various tetraethylisoindoline analogues were accessed by the oxidation of methyl groups attached to the aromatic ring to give the carboxylic acids. The increased steric bulk of the tetraethyl structures should limit bio‐reduction and these compounds may have potential as antioxidants.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Isoindoline‐Based Nitroxides as Bioresistant Spin Labels for Protein Labeling through Cysteines and Alkyne‐Bearing Noncanonical Amino Acids

“…Here, we report the synthesis, characterization and application of nitroxide labels that are based on an isoindoline ring equipped with four ethyl groups in α‐position to the nitroxide (1,1,3,3‐ t etra e thyl i soindolin‐2‐yl o xyl), for which Marx et al. introduced the acronym TEIO .…”

Direct Iodination of Isoindolines and Isoindoline Nitroxides as Precursors to Functionalized Nitroxides

“…[20] The bulkier ethyl groups generate an antioxidant with improved activity because they render the nitroxide moiety more resistant to bio-reduction in vivo. [20] The bulkier ethyl groups generate an antioxidant with improved activity because they render the nitroxide moiety more resistant to bio-reduction in vivo.…”

“…[20] HPLC chromatograms for compounds 8, 9, 12, 13, and 15-20; CIF file for X-ray crystal structure of 9. The aqueous layer was then acidified with 5 m aq.…”

Modern Synthetic Approaches to Phthalonitriles with Special Emphasis on Transition-Metal Catalyzed Cyanation Reactions

“…For example, this reaction was applied to prepare 5,6-dicyano-1,1,3,3-tetramethylisoindoline, which was subsequently hydrolized to give corresponding phthalic acid derivative as a precursor to water-soluble nitroxide radicals [30] or conformationally unambiguous spin labels for distance measurements [31] (Figure 4). …”