Jasminka Pavlinac,a Marko Zupana,b and Stojan Stavbera,*
a Department of Physical and Organic Chemistry, “Jožef Stefan” Institute, Jamova
1000 Ljubljana, Slovenia,
b Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, 1000 Ljubljana, Slovenia
* Corresponding author: E-mail: email@example.com
Lodine was efficiently introduced into the methoxy substituted aromatic compounds, acetophenone, 1-indanone and 1- tetralone using the elemental iodine / 30% aq. H2O2 system under organic solvent-free reaction conditions (SFRC) and two types of iodo-functionalisation through an electrophilic process were observed. Iodination of the aromatic ring in the case of dimethoxy- and trimethoxy benzenes took place, while aryl alkyl ketones were regioselectively iodinated at the alkyl position next to a carbonyl group. Based on the ratio of substrate : I2 : H2O2 required for the most efficient iodo- transformation, two different roles of H2O2 in the reaction route can be distinguished. Different forms of H2O2 as mediators of iodination, namely 30% aq. H2O2 and two solid forms urea-H2O2 and sodium percarbonate (2Na2CO3 · 3H2O2), were comparatively evaluated in terms of efficiency under SFRC. Reactions using 30% aq. H2O2 as the mediator of iodination under SFRC were compared with those performed in water as reaction medium.
Keywords: Green chemistry, halogenation, iodination, hydrogen peroxide, solvent-free