Brominated isoindolines: Precursors to functionalised nitroxides
Micallef, Aaron S., Bott, Raymond C., Bottle, Steven E., Smith, Graham, White, Jonathon M., Matsuda, Kenji, & Iwamura, Hiizu (1999) Brominated isoindolines: Precursors to functionalised nitroxides. Journal of the Chemical Society, Perkin 2, pp. 65-72.
A new, convenient method for the preparation of functionalised precursors to stable tetraalkylisoindoline nitroxides (aminoxyls) is presented. Simple treatment of 2-benzyl-1,1,3,3-tetramethylisoindoline 2 with Br2 in CCl4 gives rapid oxidative debenzylation, generating benzaldehyde and an unusual bromamine, 2-bromo-1,1,3,3-tetramethylisoindoline 4, in high yield. Treatment of the bromamine 4 with FeSO4 / H2SO4 results in bromination of the aromatic ring in varying yield, while rapid treatment with peroxide / tungstate causes debromination, generating 1,1,3,3-tetramethylisoindoline 3. Bromination of the isoindoline aromatic ring is more readily afforded by treatment of 2-benzyl-1,1,3,3-tetramethylisoindoline 2 with Br2 and AlCl3 in CCl4, producing 2,5-dibromo-1,1,3,3-tetramethylisoindoline 7 and/or 2,5,6-tribromo-1,1,3,3-tetramethylisoindoline 6 in varying yields depending upon the exact reaction conditions. Rapid treatment with peroxide / tungstate generates the corresponding bromine substituted isoindolines, 5-bromo-1,1,3,3-tetramethylisoindoline 5 and 5,6-dibromo-1,1,3,3-tetramethylisoindoline 8. Prolonged peroxide / tungstate treatment oxidises the substituted bromamines to the corresponding nitroxides, 5-bromo-1,1,3,3-tetramethylisoindolin-2-yloxyl 9 and 5,6-dibromo-1,1,3,3-tetramethylisoindolin-2-yloxyl 10. SQUID magnetic susceptibility measurements of crystalline 10 reveal strong antiferromagnetic interradical spin coupling. The crystal structures of 10, 2-bromo-1,1,3,3-tetramethylisoindoline 4 and the hydrobromide dihydrate salt of 1,1,3,3-tetramethylisoindoline 3 (3a) have also been determined, with 10 displaying an interesting molecular packing arrangement
Impact and interest:
Citation counts are sourced monthly from and citation databases.
These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.
Citations counts from theindexing service can be viewed at the linked Google Scholar™ search.
Full-text downloads displays the total number of times this work’s files (e.g., a PDF) have been downloaded from QUT ePrints as well as the number of downloads in the previous 365 days. The count includes downloads for all files if a work has more than one.
|Item Type:||Journal Article|
|Subjects:||Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000)|
|Divisions:||Past > QUT Faculties & Divisions > Faculty of Science and Technology|
|Copyright Owner:||Copyright 1999 Royal Society of Chemistry|
|Copyright Statement:||Reproduced by permission of The Royal Society of Chemistry, no further distribution permitted.|
|Deposited On:||18 Oct 2005 00:00|
|Last Modified:||10 Aug 2011 18:16|
Repository Staff Only: item control page