Iodination of phenols using chloramine T and sodium iodide

Kometani, Tadashi; Watt, David S.; Ji, Tae H.

doi:10.1016/s0040-4039(00)94774-9

Cited by 77 publications

(38 citation statements)

References 4 publications

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“…Iodo-resiniferatoxin was prepared in one synthetic step from resiniferatoxin by iodination using the sodium iodide/Chloramine-T reagent system (Kometani et al, 1985). Iodination occurs selectively ortho to the hydroxyl substituent and cleanly if the reaction is not forced to completion by adding excess reagents or using prolonged reaction times.…”

Section: Methodsmentioning

confidence: 99%

Functional Properties of the High-Affinity TRPV1 (VR1) Vanilloid Receptor Antagonist (4-Hydroxy-5-iodo-3-methoxyphenylacetate ester) Iodo-Resiniferatoxin

Seabrook

Sutton²,

Jarolimek³

et al. 2002

J Pharmacol Exp Ther

117

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We have synthesized iodinated resiniferatoxin bearing a 4-hydroxy-5-iodo-3-methoxyphenylacetate ester (I-RTX) and have characterized its activity on rat and human TRPV1 (VR1) receptors, as well as in behavioral assays of nociception. In whole cell patch-clamp recordings from transfected cells the functional activity of I-RTX was determined. Currents activated by capsaicin exhibited characteristic outward rectification and were antagonized by capsazepine and I-RTX. On rat TRPV1 the affinity of I-RTX was 800-fold higher than that of capsazepine (IC 50 ϭ 0.7 and 562 nM, respectively) and 10-fold higher on rat versus human receptors (IC 50 ϭ 0.7 and 5.4 nM, respectively). The same difference was observed when comparing the inhibition of [ 3 H]RTX binding to rat and human TRPV1 membranes for both RTX and I-RTX. Additional pharmacological differences were revealed using protons as the stimulus. Under these conditions capsazepine only partly blocked currents through rat TRPV1 receptors (by 70 to 80% block), yet was a full antagonist on human receptors. In contrast, I-RTX completely blocked proton-induced currents in both species and that activated by noxious heat. I-RTX also blocked capsaicin-induced firing of C-fibers in a rat in vitro skin-nerve assay. Despite this activity and the high affinity of I-RTX for rat TRPV1, only capsazepine proved to be an effective antagonist of capsaicin-induced paw flinching in rats. Thus, although I-RTX has limited utility for in vivo behavioral studies it is a high-affinity TRPV1 receptor antagonist that will be useful to characterize the functional properties of cloned and native vanilloid receptor subtypes in vitro.The transient receptor potential TRPV1 vanilloid receptor (also known as VR1; see revised TRP channel nomenclature Montell et al., 2002) gates a nonselective cation channel that is expressed by sensory neurons and that can be activated by protons, heat, and capsaicin, the pungent ingredient of chili peppers (Caterina et al., 1997;Tominaga et al., 1998). Ligands acting at the TRPV1 vanilloid receptor subtype have the potential therapeutic utility to treat thermal hyperalgesia-related pain and some inflammatory conditions (for review, see Szallasi and Blumberg, 1999;Caterina and Julius, 2001). One of the first antagonists described for the capsaicin receptor was capsazepine (Bevan et al., 1992). This ligand has been used widely to explore the functional significance of TRPV1 receptors in pain. However it has relatively low micromolar affinity for TRPV1 receptors and because it also blocks voltage-gated calcium channels, this has made interpretation of functional data with this compound less straightforward (Docherty et al., 1997).To date, one of the highest affinity ligands reported for the TRPV1 receptor is the natural plant product resiniferatoxin (RTX), which was first isolated from Euphorbia resinifera (Szallasi and Blumberg, 1989). Interestingly, it has been shown recently that iodination of this agonist RTX confers antagonist-like properties to the ligand wit...

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Section: Methodsmentioning

confidence: 99%

Functional Properties of the High-Affinity TRPV1 (VR1) Vanilloid Receptor Antagonist (4-Hydroxy-5-iodo-3-methoxyphenylacetate ester) Iodo-Resiniferatoxin

Seabrook

Sutton²,

Jarolimek³

et al. 2002

J Pharmacol Exp Ther

117

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“…Commercially available 1 .lo-phenanthroline hydrate was dried by heating at 80°C for 24 h at 0.1 mm Hg. The following compounds were prepared from the stated starting materials according to known procedures: (iodomethy1)-trimethylstannane and (iodomethy1)tributylstannane (from diiodomethane) [32], 2.4-dichloro-6-iodophenol (from 2.4-dichlorophenol) [54], and N-(2-iodopheny1)-methanesutfonamide (from 2-iodoaniline) [ (31). 463 ( 3 9 , 291 (37).…”

Section: Methodsmentioning

confidence: 99%

Isolation of Transmetalation Intermediates in the Stille Cross‐Coupling Reaction of Stannanes: Synthesis of Palladacycles, Ligand Substitution, and Insertion Reactions

Mateo

Cárdenas

Fernández-Rivas

et al. 1996

Chemistry A European J

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A strategy based on a Stille cross-coupling reaction of organostannanes interrupted at the reductive elimination step has been applied to the synthesis of oxa-and azapalladacycles with the general formula cis-[PdArR(L),] . The synthesis of oxapalladacycles was achieved under mild conditions by reaction of 2-iodo-or 2-bromophenyloxymethylstannanes with [Pd(PPh,),]. The synthesis of an aza analogue was similarly carried out from the corresponding 2-iodoaniline derivative. One of the substituted oxapalladacycles rearranged to release steric strain between the palladium and a chloride substituent on the aryl ring, an isomerization promoted by traces of water. 0 P trametalationIn one case, the arylpalladium(I1) intermediate of oxidative addition was isolated by using a palladium(o) complex with a bidentate diphosphane. A variety of new palladacycles, including complexes with weakly coordinating ligands, were prepared by ligand substitution. Reaction of the palladacycles with dimethyl acetylenedicarboxylate led to the formation of chromenes or dihydroquinolines by insertion followed by reductive elimination.

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“…Diamino acid 95 was derived from the 8-amino-1-octanol starting material in the aforementioned manner after initial N-protection [52], and a library of -benzoylated structures was achieved chemoselectively using the corresponding Fujita-reagent [57]. In the most notable case (96) concomitant deprotection of the 2-tert-butyldimethylsilyl ether (TBDMS) function was possible during -acylation under conditions of pH10-11 to give 97 (Scheme 13b), and subsequent iodination with chloramine-T [58] gave mixtures containing 3-and 5-monoiodinated, and 3,5-diiodinated species, from which the desired 3-iodinated ( 125 I-labelled) product 98 was isolated chromatographically in 13% yield [52].…”

Section: • Synthesismentioning

confidence: 99%

ω -Phosphinyl-α -Amino Acids: Synthesis, and Development towards Use as Therapeutic Agents

Wardle¹,

Bligh²,

Hudson³

2007

COC

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Literature publications (up to September 2006) concerning the synthesis of -phosphinyl--amino acids and their development towards use as therapeutic agents are reviewed. General and asymmetric methodologies for the preparation of straight-chain examples are described, including AP3-7 modulators of glutamate-responsive excitatory amino acid (EAA) receptors (i.e. ionotropic NMDA-, and metabotropic GrpIII mGlu-receptors), and the glutamate synthetase inhibitor phosphinothricin. Focusing primarily on the development of methods for introducing phosphonate and aminocarboxylate functions to the appropriate scaffold, approaches to conformationally constrained -phosphinyl--amino acids are also investigated, along with their relevance to the development of therapeutic regimens towards neurodegenerative disorders.

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Iodination of phenols using chloramine T and sodium iodide

Cited by 77 publications

References 4 publications

Functional Properties of the High-Affinity TRPV1 (VR1) Vanilloid Receptor Antagonist (4-Hydroxy-5-iodo-3-methoxyphenylacetate ester) Iodo-Resiniferatoxin

Functional Properties of the High-Affinity TRPV1 (VR1) Vanilloid Receptor Antagonist (4-Hydroxy-5-iodo-3-methoxyphenylacetate ester) Iodo-Resiniferatoxin

Isolation of Transmetalation Intermediates in the Stille Cross‐Coupling Reaction of Stannanes: Synthesis of Palladacycles, Ligand Substitution, and Insertion Reactions

ω -Phosphinyl-α -Amino Acids: Synthesis, and Development towards Use as Therapeutic Agents

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Iodination of phenols using chloramine T and sodium iodide

Cited by 77 publications

References 4 publications

Functional Properties of the High-Affinity TRPV1 (VR1) Vanilloid Receptor Antagonist (4-Hydroxy-5-iodo-3-methoxyphenylacetate ester) Iodo-Resiniferatoxin

Functional Properties of the High-Affinity TRPV1 (VR1) Vanilloid Receptor Antagonist (4-Hydroxy-5-iodo-3-methoxyphenylacetate ester) Iodo-Resiniferatoxin

Isolation of Transmetalation Intermediates in the Stille Cross‐Coupling Reaction of Stannanes: Synthesis of Palladacycles, Ligand Substitution, and Insertion Reactions

&#969; -Phosphinyl-&#945; -Amino Acids: Synthesis, and Development towards Use as Therapeutic Agents

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ω -Phosphinyl-α -Amino Acids: Synthesis, and Development towards Use as Therapeutic Agents