Superactivity and dual reactivity of the system N-iodosuccinimide-H2SO4 in the iodination of deactivated arenes

Chaikovskii, V. K.; Филимонов, В. Д.; Skorokhodov, V. I.; Огородников, В. Д.

doi:10.1134/s1070428007090035

Cited by 13 publications

(13 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Detailed GC-MS study on the products of reactions of compound I with TIG-H 2 SO 4 , DIH-H 2 SO 4 , and NIS-H 2 SO 4 showed ( Table 1) that the use of stoichiometric amounts of the reagents (calculated on the active iodine) does not ensure complete conversion of I (Table 1, run nos. 1-3), and 30-35% of the initial compound remains unchanged.A similar conversion of other substrates at the same reagent-to-substrate ratio was noted by us previously [3][4][5][6]. Approximately similar selectivities were observed in the iodination with TIG-H 2 SO 4 and DIH-H 2 SO 4 .…”

supporting

confidence: 77%

“…A similar conversion of other substrates at the same reagent-to-substrate ratio was noted by us previously [3][4][5][6]. Approximately similar selectivities were observed in the iodination with TIG-H 2 SO 4 and DIH-H 2 SO 4 .…”

supporting

confidence: 77%

“…In the iodination with common iodinating systems, the reactivity and selectivity may be evaluated using the reaction with toluene as an example [2]. However, the procedure based on determination of the ratio of o-and p-iodotoluenes cannot be applied to reactions with superelectrophilic iodinating systems [3][4][5][6], which lead to the formation of a mixture of polyiodotoluenes containing mostly tri-and tetraiodo derivatives. Therefore, to estimate the selectivity of superelectrophilic iodinating systems we compared the compositions of products formed in the iodination of o-nitrotoluene (I) with reagents generated by dissolution of 1,3,4,6-tetraiodoglycoluril (TIG), 1,3-diiodo-5,5-dimethylhydantoin (DIH), and N-iodosuccinimide (NIS) in sulfuric acid [3,5,6] (Scheme 1).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Evaluation of the reactivity and regioselectivity of superelectrophilic iodinating systems

2009

Self Cite

View full text Add to dashboard Cite

Iodination of o-nitrotoluene in H 2 SO 4 or CF 3 SO 3 H at 0°C with compounds having a nitrogeniodine bond leads to the formation of isomeric mono-and diiodo derivatives whose ratio differs from the statistical value. The reaction of nitrobenzene with 2 equiv of N-I reagents in trifluoromethanesulfonic acid at 0°C takes less than 1 min and yields 79-85% of m-iodonitrobenzene. The electrophilic reactivity of the iodinating agents was estimated by quantum-chemical methods.The rate of electrophilic substitution reactions in the aromatic series and isomeric composition of the products are largely determined by the electrophile nature. In keeping with the Brown selectivity relationship, stronger electrophiles exhibit lower intramolecular selectivity in substitution reactions in the benzene ring [1]. The most reactive electrophiles give rise to a mixture of regioisomers whose ratio approaches statistical value. In the iodination with common iodinating systems, the reactivity and selectivity may be evaluated using the reaction with toluene as an example [2]. However, the procedure based on determination of the ratio of o-and p-iodotoluenes cannot be applied to reactions with superelectrophilic iodinating systems [3][4][5][6], which lead to the formation of a mixture of polyiodotoluenes containing mostly tri-and tetraiodo derivatives. Therefore, to estimate the selectivity of superelectrophilic iodinating systems we compared the compositions of products formed in the iodination of o-nitrotoluene (I) with reagents generated by dissolution of 1,3,4,6-tetraiodoglycoluril (TIG), 1,3-diiodo-5,5-dimethylhydantoin (DIH), and N-iodosuccinimide (NIS) in sulfuric acid [3, 5, 6] (Scheme 1).Traditional methods for the determination of the reactivity and regioselectivity of iodinating systems by analysis of the iodination products of nitroarene I cannot be used, for nitrotoluenes do not undergo iodination by common methods at 0°C. Detailed GC-MS study on the products of reactions of compound I with TIG-H 2 SO 4 , DIH-H 2 SO 4 , and NIS-H 2 SO 4 showed ( Table 1) that the use of stoichiometric amounts of the reagents (calculated on the active iodine) does not ensure complete conversion of I (Table 1, run nos. 1-3), and 30-35% of the initial compound remains unchanged.A similar conversion of other substrates at the same reagent-to-substrate ratio was noted by us previously [3][4][5][6]. Approximately similar selectivities were observed in the iodination with TIG-H 2 SO 4 and DIH-H 2 SO 4 . In the reaction with N-iodosuccinimide, the fraction of 4-iodo-2-nitrotoluene (II) was slightly larger than the fraction of 6-iodo-2-nitrotoluene (III), but the substrate conversion was lower.The reactions in the presence of 2 equiv of the iodinating agents (Table 1, run nos. 4-6) are characterized by appreciably reduced para-selectivity. However,

show abstract

supporting

confidence: 77%

supporting

confidence: 77%

mentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of the reactivity and regioselectivity of superelectrophilic iodinating systems

2009

Self Cite

View full text Add to dashboard Cite

show abstract

“…The silyl-containing compound 3 was desilylated on treatment with K 2 CO 3 , to produce 3,6-diethynyl-9,10-diethoxyphenanthrene (4) (Scheme 1). Rather than proceed via bromination, iodination of 1 was tried using several procedures; however, most of these attempts produced 3,6-diiodophenanthrenedione as the main product, together with many inseparable side-products [43][44][45]. The organic precursors were characterized by a combination of elemental analyses, mass spectrometry and IR, and 1 H and 13 C-NMR spectroscopies.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

DNA-Binding and Anticancer Activity of Binuclear Gold(I) Alkynyl Complexes with a Phenanthrenyl Bridging Ligand

et al. 2020

View full text Add to dashboard Cite

3,6-Diethynyl-9,10-diethoxyphenanthrene (4) was synthesized from phenanthrene and employed in the synthesis of the binuclear gold(I) alkynyl complexes (R3P)Au(C≡C–3-[C14H6-9,10-diethoxy]-6–C≡C)Au(PR3) (R = Ph (5a), Cy (5b)). The diyne 4 and complexes 5a and 5b were characterized by NMR spectroscopy, mass spectrometry, and elemental analysis. UV-Vis spectroscopy studies of the metal complexes and precursor diyne show strong π → π* transitions in the near UV region that red shift by ca. 50 nm upon coordination at the gold centers. The emission spectrum of 4 shows an intense fluorescence band centered at 420 nm which red shifts, slightly upon coordination of 4 to gold. Binding studies of 4, 5a, and 5b against calf thymus DNA were carried out, revealing that 4, 5a, and 5b have ≥40% stronger binding affinities than the commonly used intercalating agent ethidium bromide. The molecular docking scores of 4, 5a, and 5b with B-DNA suggest a similar trend in behavior to that observed in the DNA-binding study. Unlike the ligand 4, promising anticancer properties for 5a and 5b were observed against several cell lines; the DNA binding capability of the precursor alkyne was maintained, and its anticancer efficacy enhanced by the gold centers. Such phenanthrenyl complexes could be promising candidates in certain biological applications because the two components (phenanthrenyl bridge and metal centers) can be altered independently to improve the targeting of the complex, as well as the biological and physicochemical properties.

show abstract

“…For example, N-iodosuccinimide in one of the strongest acids, trifluoromethanesulfonic acid, is capable of iodinating deactivated arenes, in particular nitrobenzene, at room temperature due to formation of iodine trifluoromethanesulfonate ISO 3 CF 3 as a hypoiodite-like species [6]. Enhancement of the reactivity of N-iodosucinimide was also observed in the presence of CF 3 COOH [7] and H 2 SO 4 [8,9], presumably due to generation in situ of CF 3 COOI and IOSO 3 H. This may be illustrated by Scheme 1 where HY is a protic acid, and IY is a hypoiodite-like species with enhanced electrophilicity. Likewise, 1,3-diiodo-5,5-dimethylhydantoin [9] and tetraiodoglycoluril [10] were reported to behave similarly in concentrated sulfuric acid.…”

mentioning

confidence: 91%

Quantum-chemical study on the relation between thermodynamic parameters in the iodination of benzene with N-I and O-I reagents and pK a values of the corresponding NH and oh acids

Функ

Chaikovskii

2010

Russ J Org Chem

Self Cite

View full text Add to dashboard Cite

Thermodynamic parameters of direct iodination of benzene with several iodinating agents were calculated using semiempirical (PM3), ab initio (3-21G**), and DFT (B3LYP/LanL2DZ) methods, as well as in terms of the polarization continuum model (PCM or Tomasi model). A close to linear correlation was found between the calculated thermodynamic parameters (ΔH ≠ , ΔG ≠ ) and pK T and experimental pK a values of acids whose anions are incorporated into iodine-containing intermediates.Methods for direct iodination of aromatic compounds may be divided into two large groups. The first group includes procedures utilizing a combination of molecular iodine and an oxidant, and the set of available oxidants is very wide. Methods of the second group are based on the use of compounds having an iodine-heteroatom bond. Strong electronegativity of the heteroatom in such compounds induces a partial positive charge on the iodine atom, so that its electrophilicity increases. Examples of oxidative iodinating systems are I 2 -HNO 3 -H 2 SO 4 -AcOH, I 2 -oleum, I 2 -CrO 3 , I 2 -HgO, I 2 -HIO 3 , I 2 -HIO 4 , I 2 -KMnO 4 , I 2 -CH 3 CO 3 H, I 2 -PhI(OCOCF 3 ) 2 , etc.[1]. Most of these systems are capable of iodinating not only activated but also some deactivated arenes. In all cases, oxidation of molecular iodine with formation of electrophilic intermediates like I + or I 3 + is assumed.Iodinating reagents possessing iodine-heteroatom bonds include: iodine chloride (ICl), hypoiodites (HOI, CH 3 COOI, CF 3 COOI, HSO 3 OI, TsOI, TfOI), N-iodo imides (N-iodosuccinimide [1], N-iodosaccharin [2], 1,3-diiodo-5,5-dimethylhydantoin [3], tetraiodoglycoluril [4]), and N-iodoacetamide [5]. Iodine chloride, N-iodo imides, and N-iodoacetamide are fairly stable compounds, whereas hypoiodite-like compounds are only postulated as independent iodinating species generated in situ from iodinating reagent and the corresponding acid. It is well known that ICl, N-iodo imides, and N-iodoacetamide are weak iodinating agents, and their activity considerably increases upon addition of strong acids such as sulfuric, trifluoroacetic, trifluoromethanesulfonic, etc. For example, N-iodosuccinimide in one of the strongest acids, trifluoromethanesulfonic acid, is capable of iodinating deactivated arenes, in particular nitrobenzene, at room temperature due to formation of iodine trifluoromethanesulfonate ISO 3 CF 3 as a hypoiodite-like species [6]. Enhancement of the reactivity of N-iodosucinimide was also observed in the presence of CF 3 COOH [7] and H 2 SO 4 [8,9], presumably due to generation in situ of CF 3 COOI and IOSO 3 H. This may be illustrated by Scheme 1 where HY is a protic acid, and IY is a hypoiodite-like species with enhanced electrophilicity. Likewise, 1,3-diiodo-5,5-dimethylhydantoin [9] and tetraiodoglycoluril [10] were reported to behave similarly in concentrated sulfuric acid.Although available experimental data show that the electrophilicity of iodine species generated in strongly acidic medium considerably increases, no quantitative studies were perf...

show abstract

Superactivity and dual reactivity of the system N-iodosuccinimide-H2SO4 in the iodination of deactivated arenes

Cited by 13 publications

References 11 publications

Evaluation of the reactivity and regioselectivity of superelectrophilic iodinating systems

Evaluation of the reactivity and regioselectivity of superelectrophilic iodinating systems

DNA-Binding and Anticancer Activity of Binuclear Gold(I) Alkynyl Complexes with a Phenanthrenyl Bridging Ligand

Quantum-chemical study on the relation between thermodynamic parameters in the iodination of benzene with N-I and O-I reagents and pK a values of the corresponding NH and oh acids

Contact Info

Product

Resources

About