Molecules 2005, 10
405
Conventionally Heated Iodination Reactions
H5IO6 (1.43 g, 6.25 mmol; 25% excess), finely powdered I2 (3.81 g, 15.0 mmol; 0% excess), and
then an appropriate arene (35.0 mmol; 0% excess) [for the diiodination of thiophene 17.5 mmol, 0%
excess] were suspended in 95% ethanol (15 mL). The reaction mixtures were stirred and heated under
a reflux condenser at ca. 60 °C for 30-60 min (Table 1). The cooled reaction mixtures were quenched
by pouring them into stirred ice-water (100 g) containing prior dissolved Na2SO3 (5 g). The oily crude
iodinated products were extracted with CHCl3 (3 x 20 mL), the collected extracts were dried over anh.
MgSO4, filtered, the solvent was distilled off, and the oily residues were fractionated under vacuum to
give the purified liquid products (Table 1). The solid crude products were collected by filtration,
washed well with cold water, dried preliminarily by the suction, and next air-dried in the dark. They
were recrystallized from appropriate organic solvents to give the purified solid products (Table 1).
Microwave-Accelerated Iodination Reactions
The same as above amounts of H5IO6, I2, and the appropriate arene were suspended in 95% ethanol
(25 mL). The reaction mixtures were put into the microwave cavity, and the magnetic stirrer was
switched on. An appropriate power output was applied (50%, 500 W) to secure a slight, uninterrupted
boil of the solvent under a reflux condenser attached outside. After a definite time (1-10 min, see the
Table 1), the reaction mixtures were cooled to r.t., and then they were poured, as above, into stirred
ice-water (100 g) containing Na2SO3 (5 g). The following workups and purification of the oily or solid
crude products were quite the same as above. For the final results thus obtained see the Table 1.
References and Notes
1. a) Microwave-Enhanced Chemistry Fundamentals, Sample Preparation and Application.
Kingston, H. M.; Haswell, S. J., Eds.; American Chemical Society: Washington, D.C., 1997; b)
Microwaves in Organic Synthesis. Loupy, A., Ed.; Wiley-VCH: Weinheim, 2002; c) Microwave
Synthesis; Chemistry at the Speed of Light. Hayes, B. L., Ed.; CEM Publishing: Matthews, NC,
2002.
2. Perreaux, L.; Loupy, A. A tentative realization of microwave effects in organic synthesis
according to the reaction medium, and mechanistic consideration. Tetrahedron 2001, 57, 9199-
9223. A review.
3. Lindstroem, P.; Tierney, J.; Whathey, B.; Westman, J. Microwave assisted organic synthesis – a
review. Tetrahedron 2001, 57, 9225-9283.
4. Fini, A.; Breccia, A. Chemistry by Microwaves. Pure Appl. Chem. 1999, 71, 573-579. A review.
5. Sosnowski, M.; Skulski, L. Microwave-Accelerated Iodination of Some Aromatic Amines, Using
Urea-Hydrogen Peroxide Addition Compound (UHP) as the Oxidant. Molecules 2002, 7, 867-
Sixth
Electronic
Conference
on
Synthetic
Organic
Chemistry
(ECSOC-6,
http://www.mdpi.net/ecsoc-6), September 1-30, 2002 (paper E006).