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
作者:Andreas Groß、Nina Schneiders、Kristina Daniel、Thomas Gottwald、Jens Hartung
DOI:10.1016/j.tet.2008.09.006
日期:2008.11
Methoxyl and isopropoxyl radicals were generated from N-alkoxy-4,5-dimethylthiazole-2(3H)-thiones (λmax∼320 nm) and 5-aryl derivatives (aryl=p-XC6H4; X=MeO, H, AcNH, Cl) (λmax∼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
甲氧基和异丙氧基的基团从生成的ñ -烷氧基-4,5-二甲基噻唑-2(3 H ^)-thiones(λ最大~320纳米)和5-芳基衍生物(芳= p -XC 6 ħ 4 ; X =的MeO, H,AcNH,Cl)的(λ最大~335纳米)在光化学和微波诱导的反应。烷氧基被二甲基吡咯烷N-氧化物捕获并通过EPR表征为自旋加合物。枯基氧基以类似的方式从N-枯基氧基-5-(4-甲氧基苯基)-4-甲基噻唑-2(3 H)-硫酮中释放出来。N的最低能量跃迁发现了值得注意的红移- (羟基)茚并[2,1- d ]噻唑-2(3 H ^) -硫酮(λ最大= 376纳米),如果相比的UV-vis吸收ñ -羟基-4-甲基-5- phenylthiazole- 2(3 ħ) -硫酮(λ最大= 338纳米)。全面描述了烷氧基自由基前体的合成和进行N,O均解的程序。