Synthesis of 3‐Aryloxy‐2‐iodoemodines by Oxidation of Emodin with (Diacetoxyiodo)arenes

Daub, Katja S.; Habermann, Bernd; Hahn, Thilo; Teich, Lars; Eger, Kurt

doi:10.1002/ejoc.200300317

Cited by 16 publications

(18 citation statements)

References 23 publications

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“…38 mp = 120–122 °C; lit. 39 mp = 112–119 °C). 1 H-NMR (CDCl 3 ) δ 7.78 (dd, J = 1.2, 3.6 Hz, 1H), 7.64 (dd, J = 1.2, 5.2 Hz, 1H), 7.15–7.13 (m, 1H), 2.02 (s, 6H); 13 C NMR (CDCl 3 ) δ 177.0, 139.1, 134.9, 128.7, 106.3, 20.4.…”

Section: Methodsmentioning

confidence: 99%

Regiospecific Syntheses of Functionalized Diaryliodonium Tosylates via [Hydroxy(tosyloxy)iodo]arenes Generated in Situ from (Diacetoxyiodo)arenes

Chun

Pike

2012

J. Org. Chem.

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Ready access to 18F-labeled aryl synthons is required for preparing novel radiotracers for molecular imaging with positron emission tomography. Diaryiodonium salts react with cyclotron-produced no-carrier-added [18F]fluoride ion to produce [18F]aryl fluorides. We aimed to prepare functionalized diaryliodonium salts to serve as potential precursors for producing useful 18F-labeled aryl synthons, such as 18F-labeled halomethylbenzenes, benzaldehydes and benzoic acid esters. Such salts were designed to have one functionalized aryl ring, one relatively electron-rich ring, such as 4-methoxyphenyl or 2-thienyl, and a non-fluorine containing weakly nucleophilic anion. Generation of a [hydroxy(tosyloxy)iodo]arene from a functionalized (diacetoxyiodo)arene in situ followed by treatment with an electron-rich arene, such as anisole or thiophene, or with a functionalized arylstannane gave expedient regiospecific access to a wide range of functionally diverse diaryliodonium tosylates in moderate to high yields (44–98%). The described methodology broadens the scope for producing new functionalized diaryliodonium salts for diverse applications.

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Section: Methodsmentioning

confidence: 99%

Regiospecific Syntheses of Functionalized Diaryliodonium Tosylates via [Hydroxy(tosyloxy)iodo]arenes Generated in Situ from (Diacetoxyiodo)arenes

Chun

Pike

2012

J. Org. Chem.

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“…The aqua crown ether complex 4 a was obtained in 91 % yield as a white powder after repeated decantation with hexane and diethyl ether at À40 8C. Complex 4 b was prepared in a similar way from 3,5-dimethyl(diacetoxyiodo)-benzene [7] in 92 % yield. The aqua complex 4 a is soluble in dichloromethane, chloroform, acetonitrile, acetone, and methanol, but not in the less polar solvents diethyl ether and hexane.…”

mentioning

confidence: 99%

“…ORTEP drawing of 4a. Selected bond lengths [] and angles [8]: I1ÀC1 2.117(2), I1ÀO2 1.967(2), I1ÀO1 2.392(2), I1···O7 2.942(2), O3···H1 2.04(4), O5···H2 1.91(4), O9···H3 1.9582, C1-I1-O2 92.32(3), C1-I1-O1 81.80(8), O2-I1-O1 173.96(7). Scheme 1.…”

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confidence: 99%

Synthesis, Characterization, and Reaction of Crown Ether Complexes of Aqua(hydroxy)(aryl)iodonium Ions

et al. 2004

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The Koser reagent, [hydroxy(tosyloxy)iodo]benzene (1; Ts = p-toluenesulfonyl), is a useful oxidizing agent for a range of organic substrates.[1] It has been reported that upon dissolution in water the l 3 -iodane undergoes complete ionization to give the hydroxy(phenyl)iodonium cation (PhI + OH).[2] The hydroxy(phenyl)iodonium ion does not form an ion pair with a tosylate ion and is presumed to be ligated with at least one water molecule at an apical site of the iodine(iii) center. This aqua(hydroxy)(phenyl)iodonium ion 2 (L = H 2 O) is highly soluble in water with a pK a value of 4.30 at 20 8C.Iodosylbenzene is a polymer bridged by secondary I···O hypervalent interactions, [3] and hence is essentially insoluble in both nonreactive organic solvents and water at near neutral pH conditions; [4] however, at pH < 2.3 iodosylbenzene is highly soluble in water, in which 2 (L = H 2 O) was also assumed to be a primary monomeric species. [2] Aqua complexes of l 3 -iodanes with a water molecule coordinated to an iodine(iii) center are unique, and there are no well-established precedents. Therefore, direct evidence supporting the proposed structure of 2 (L = H 2 O) is highly desirable. Recently, Wirth and co-workers synthesized an interesting chiral hydroxyiodonium ion 3, in which the oxygen atom of the ortho methoxymethyl group replaces the tosylate ligand of the Koser reagent with a near-linear O À I···O triad. [5] We have reported the isolation and characterization of the crown ether complex 2·BF 4 À (L = [18]crown-6) of hydroxy-(phenyl)iodonium ion. In this complex, an oxygen atom of the crown ether is tightly bound to the iodine(iii) center at the apical site and forms a T-shaped structure with linear OÀI···O hypervalent bonding.[6] Herein, we report the first synthesis

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“…12 The iodonium nitrophenolate 22b is stable enough to afford the benzofuran regioisomers 27 and 28 through its reaction with alkynes under photochemical conditions.…”

Section: Methodsmentioning

confidence: 99%

Zwitterionic Iodonium Compounds: Useful Tools in Organic Synthesis

Malamidou‐Xenikaki¹,

Spyroudis²

2008

Synlett

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Synthesis of 3‐Aryloxy‐2‐iodoemodines by Oxidation of Emodin with (Diacetoxyiodo)arenes

Cited by 16 publications

References 23 publications

Regiospecific Syntheses of Functionalized Diaryliodonium Tosylates via [Hydroxy(tosyloxy)iodo]arenes Generated in Situ from (Diacetoxyiodo)arenes

Regiospecific Syntheses of Functionalized Diaryliodonium Tosylates via [Hydroxy(tosyloxy)iodo]arenes Generated in Situ from (Diacetoxyiodo)arenes

Synthesis, Characterization, and Reaction of Crown Ether Complexes of Aqua(hydroxy)(aryl)iodonium Ions

Zwitterionic Iodonium Compounds: Useful Tools in Organic Synthesis

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