We devised a practical synthetic route to azobenzenophanes via successive Cu- and Pd-catalyzed coupling reaction of aryl hydrazide and aryl halide followed by Cu(I)-mediated oxidation reaction.
from NaIO 4 and either I 2 or KI in concentrated H 2 SO 4 (minimum 95% by weight). In general a small excess of the dark brown iodinating solution was used (1.1/1.5 equivalents, for nitrobenzene two equivalents was required). The iodinations were conducted at 25-30 °C with a reaction time of 1-2 hours using either a 'direct' or an 'inverse' method of aromatic iodination to give mono- or diiodinated pure
用强亲电 I + 试剂对失活的芳烃进行单碘化或二碘化,这些试剂由 NaIO 4 和 I 2 或 KI 在浓 H 2 SO 4 中制备(至少 95% 重量)。通常使用稍微过量的深棕色碘化溶液(1.1/1.5 当量,对于硝基苯需要两个当量)。碘化在 25-30 °C 下进行,反应时间为 1-2 小时,使用芳香族碘化的“直接”或“反向”方法以 31-91% 的优化产率得到单碘化或二碘化纯产物。
Iodination of Both Deactivated and Activated Arenes with Sodium Periodate or Sodium Iodate as the Oxidants
作者:Piotr Lulinski、Lech Skulski
DOI:10.1246/bcsj.73.951
日期:2000.4
Five easy, relatively inexpensive, and environmentally-safe aromatic oxidative iodination procedures are presented; three of them are particularly suitable for deactivated arenes. Nine deactivated arenes, four halobenzenes, benzene, toluene, and N,N-dimethylaniline were reacted upon with the following anhydrous systems: diiodine/NaIO4 or (in four cases) NaIO3/acetic anhydride/glacial acetic acid, acidified with varying amounts of concd (98%) sulfuric acid; the following workups are explained. The aromatic oxidative iodination reactions proceeded mostly at room temperature and within 1—8 h to give fifteen mono- and two diiodinated purified products (sometimes obtained in 2—3 different ways) in 51—95% yields.
Eco-friendly Oxidative Iodination of Various Arenes with Sodium Percarbonate as the Oxidant†
作者:Agnieszka Zielinska、Lech Skulski
DOI:10.3390/10101307
日期:——
Six easy laboratory procedures are presented for the oxidative iodination of various aromatics, mostly arenes, with either molecular iodine or potassium iodide (used as the sources of iodinating species, I+ or I3+), in the presence of sodiumpercarbonate (SPC), a stable, cheap, easy to handle, and eco-friendly commercial oxidant.
Three easy eco-friendly laboratory procedures are presented for the oxidative iodination of various activated and deactivated arenes with molecular iodine, in the presence of UHP (percarbamide), a stable, strongly H-bonded, solid urea-hydrogen peroxide adduct as the oxidant.
After comparing our previous and newer results for numerous oxidative aromatic iodination experiments using various brands of active MnO2 as the oxidants,we recommend the use of a Chemical ManganeseDioxide (Aldrich CMD; 90 +% MnO2) as the oxidant of choice, since it is satisfactorily pure and chemically active, and is notably less costly than other options.