Synthesis of new 3,4-disubstituted 2,5-dihydro-1H-pyrrol-1-yloxyl spin-label reagents via allylic rearrangements

K. Hideg, C. P. Sar, O. H. Hankovszky, T. Tamas, G. Jerkovich

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Several 3,4-disubstituted 2,5-dihydro-1H-pyrrol-1-yloxyl radicals were synthesized. 2,5-Dihydro-3-hydroxymethyl-2,2,5,5-tetramethyl-1H-pyrrol-1-yloxyl radical (1) was reacted with triethyl orthoacetate in a Claisen rearrangement to give the exoolefinic compound 2. This was converted to its 1-acetoxyl derivate 3, which was then brominated in the allylic position. Subsequent rearrangement gave the endoolefinic compound 1-acetoxyl-4-bromomethyl-3-ethoxy-carbonylmethyl-2,2,5,5-tetramethyl- 1H-pyrrole radical (4). The allylic bromine could be replaced with nucleophiles (NaSCN, KSeCN, thiourea, selenourea, NaN3 and KSSO2Me) to give 5a-e and 26. The diamagnetic thiocyanates and selenocyanates could be reduced with sodium borohydride to the free thiol and selenol monoradicals, which were oxidized to reversible, ester-functionalized disulfide or diselenide diradical reagents 24 and 25.

Original languageEnglish
Pages (from-to)390-394
Number of pages5
JournalSynthesis
Issue number4
DOIs
Publication statusPublished - Jan 1 1993

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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