Spin trapping of alkoxyl radicals generated from 5-methyl and 5-aryl-3-alkoxy-4-methylthiazole-2(3H)-thiones in photochemically induced and microwave-initiated reactions
TETRAHEDRON. Bd. 64. H. 48. 2008 S. 10882 - 10889
Erscheinungsjahr: 2008
ISBN/ISSN: 0040-4020
Publikationstyp: Zeitschriftenaufsatz
Doi/URN: 10.1016/j.tet.2008.09.006
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Inhaltszusammenfassung
Methoxyl and isopropoxyl radicals were generated from N-alkoxy-4,5-dimethylthiazole-2(3H)-thiones (lambda(max) similar to 320 nm) and 5-aryl derivatives (aryl-p-XC6H4; X=MeO, H, AcNH, Cl) (lambda(max) similar to 335 nm) in photochemically and microwave-induced reactions. Alkoxyl radicals were trapped with dimethylpyrrolidine N-oxide and characterized as spin adducts via EPR. Cumyloxyl radicals were liberated in a similar manner from N-cumyloxy-5-(4-methoxyphenyl)-4-methylthiazole-2(3H)-thione...Methoxyl and isopropoxyl radicals were generated from N-alkoxy-4,5-dimethylthiazole-2(3H)-thiones (lambda(max) similar to 320 nm) and 5-aryl derivatives (aryl-p-XC6H4; X=MeO, H, AcNH, Cl) (lambda(max) similar to 335 nm) in photochemically and microwave-induced reactions. Alkoxyl radicals were trapped with dimethylpyrrolidine N-oxide and characterized as spin adducts via EPR. Cumyloxyl radicals were liberated in a similar manner from N-cumyloxy-5-(4-methoxyphenyl)-4-methylthiazole-2(3H)-thione. A noteworthy bathochromic shift was found for the lowest energy transition of N-(hydroxy)indeno[2,1-d]thiazole-2(3H)-thione (lambda(max)=376 nm), if compared to the UV-vis absorption of N-hydroxy-4-methyl-5-phenylthiazole-2(3H)-thione (lambda(max)=338 nm). Syntheses of alkoxyl radical precursors and procedures for conducting N,O-homolysis are described in a full account. (C) 2008 Elsevier Ltd. All rights reserved. » weiterlesen» einklappen