5100
S. Adimurthy et al. / Tetrahedron Letters 44 (2003) 5099–5101
Table 1. Iodination for aromatic compounds with KI/
KIO3/H+
Thus, we have reported our findings on the use of a
simple reagent system for an environmentally benign
and efficient procedure for the iodination of aromatic
compounds.
General procedure for the iodination:
4-Iodoanisole: A solution of anisole (1.00 g; 9.26 mmol),
potassium iodide (1.03 g; 6.22 mmol) and potassium
iodate (0.66 g; 3.08 mmol) was prepared in methanol (5
mL) and water (30 mL). This mixture was treated at
room temperature with dilute hydrochloric acid (9.5
mmol) over 40 to 45 minutes and stirred for an addi-
tional 2–3 h, diluted with water (50 mL) and extracted
with dichloromethane (25 mL×3). The combined
organic extract was washed with dilute sodium thiosul-
phate (5%), water, brine, dried over anhydrous sodium
sulphate and concentrated under reduced pressure to
give a thick oil (1.94 g; 90%). Further purification was
carried out by crystallization from cold hexane to
afford a white crystalline product (1.75 g; 81%), mp
52–54°C (Lit.19 53–54°C), which showed satisfactory
analytical and spectroscopic properties.
Acknowledgements
The authors wish to thank CSIR, New Delhi for the
financial assistance to A.V.B. under the Quick Hire
Scheme.
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for aromatic iodination describes a very low yield of
4-iodo-N,N-dimethylaniline from N,N-dimethylaniline.
It is remarkable to observe that the present reagent
system was very effective for this particular substrate
resulting in an excellent yield of 4-iodo-N,N-dimethyl-
aniline. The iodinated products reported in this study
were isolated by column chromatography over silica gel
and characterized by standard analytical means and by
comparison of their melting points with those reported.