Molecules 2001, 6
889
H, 1.7; I, 45.4; calcd: C, 30.03; H, 1.80; I, 45.32. h) For the pure 4-iodylbenzoic acid, C7H5IO4: found: C, 30.0;
H, 1.8; I, 45.3; calcd: C, 30.03; H, 1.80; I, 45.32.
Preparation of “2-Iodylbenzoic acid”, i. e. 1-Hydroxy-1,2-benziodoxol-3(1H)-one-1-oxide:
2-Iodobenzoic acid (2.48 g, 10 mmol) was slowly added portionwise, with stirring, to a solution of
NaHCO3 (0.86 g, 10.2 mmol) in water (20 mL) (foaming!). Next, NaIO4 (4.70 g, 22 mmol; 10%
excess) was added, and the mixture was stirred and refluxed for 12 h. After cooling to r.t., this was
poured, with stirring, into water (50 mL) acidified with conc. (98%) H2SO4 (0.6 mL). The strongly
acidic mixture (Congo Red) was left at r.t. for 30 min. The white precipitate was collected by filtration,
washed thoroughly with cold water (2 x 10 mL) next with Me2CO to remove the unreacted 2-
HOOCC6H4I, and air-dried in the dark to give 71% crude yield. Small crude sample was recrystallized
from boiling water to give the analytically pure product. The same procedure is appropriate for the
preparation of 4-iodylbenzoic acid, obtained from 4-IC6H4COONa (10 mmol) in 88% crude yield.
These two crude products did not oxidize KI in a saturated sodium borate solution, a reaction which
differentiates iodosyl compounds from iodyl compounds [15].
References and Notes
1. Willgerodt, C. Die organischen Verbindungen mit mehrwertigem Jod; Enke Verlag: Stuttgart,
1914.
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E.B. Usp. Khim. 1987, 56, 1444; pp 1453-1467 [Chem. Abstr. 1988, 108, 204265]; c) Kirschning,
A. J. Prakt. Chem./Chem.-Ztg. 1998, 340, 184; d) Pohnert, G. J. Prakt. Chem. 2000, 342, 731; e)
Tohma, H. Yakugaku Zasshi 2000, 120, 620 [Chem. Abstr. 2000, 133, 222460]; f) Arisawa, M.;
Toma, H.; Kita, Y. Yakugaku Zasshi 2000, 120, 1061 [Chem. Abstr. 2001, 134, 29586].
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4. Stang, P.J.; Zhdankin, V.V. Chem. Rev. 1996, 96, 1123.
5. Varvoglis, A. Hypervalent Iodine in Organic Synthesis; Academic Press: San Diego, 1997.
6. Recent reviews on organohypervalent iodine compounds and their applications in organic
synthesis: a) Kitamura, T.; Fujiwara, Y. Org. Prep. Proced. Int. 1997, 29, 409; b) Varvoglis, A.
Tetrahedron 1997, 53, 1179; c) Muraki, T.; Togo, H.; Yokoyama, M. Rev. Heteroatom Chem.
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Togo, H.; Hoshina, Y.; Nogami, G.; Yokoyama, M. Yuki Gosei Kagaku Kyokaishi 1997, 55, 90
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Tetrahedron 1998, 54, 10927; i) Varvoglis, A.; Spyroudis, S. Synlett 1998, 221; j) Ochiai, M.
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