Use Of Molecular Iodine Research Articles

Comparing the Use of Molecular Iodine and Copper(II) Compounds as an Oxidizing Agent of Metals and Alloys under Regeneration thereof in the Course of Processing

Comparing the Use of Molecular Iodine and Copper(II) Compounds as an Oxidizing Agent of Metals and Alloys under Regeneration thereof in the Course of Processing

IEDDA Reaction of the Molecular Iodine-Catalyzed Synthesis of 1,3,5-Triazines via Functionalization of the sp3 C-H Bond of Acetophenones with Amidines: An Experimental Investigation and DFT Study.

The present work reports an inverse electron demand Diels-Alder (iEDDA)-type reaction to synthesize 1,3,5-trizines from acetophenones and amidines. The use of molecular iodine in a catalytic amount facilitates the functionalization of the sp3 C-H bond of acetophenones. This is a simple and efficient methodology for the synthesis of 1,3,5-triazines in good to excellent yields under transition-metal-free and peroxide-free conditions. The reaction is believed to take place via an in situ iodination-based oxidative elimination of formaldehyde. DFT calculations at the M062X/6-31+G(d,p) level were employed to investigate the reaction mechanism. Reaction barriers for the cycloaddition as well as a formaldehyde expulsion steps were computed, and a multistep mechanism starting with the nucleophilic attack by benzamidine on an in situ generated imine intermediate has been proposed. Both local and global reactivity descriptors were used to study the regioselectivity of the addition steps.

Abstract 2243: Elucidating the mechanism of action of molecular iodine on breast cancer cells

Abstract Each year, over 1.7 million women are diagnosed with breast cancer worldwide and about 35% of these diagnosed are expected to die from the disease. A significant barrier to improving treatment of breast cancer lies in our incomplete understanding of breast cancer initiation and metastasis. Regular use of molecular iodine has been shown to reduce the sensitivity of breast cells to the proliferative effects of estrogen, resulting in normalization of breast tissue.The aim of the current study was to evaluate the mechanisms of molecular iodine on two common breast cancer sub-types using well-established breast cancer cell lines. In order to study Luminal A and triple-negative breast cancer in vitro, MCF7 (cells from a luminal A subtype) and MDA-MB231 (cells from a triple-negative subtype), were treated with molecular iodine at various concentrations to measure proliferation and cell death. This was subsequently followed by gene expression analysis of key important molecular markers, which are primarily responsible for cell growth and apoptosis. Primary human mammary epithelial cells derived from healthy female donor were used as an internal control. Data from this study indicated that molecular iodine had potent inhibitory effects on cell growth and showed a dramatic increase in cell death in both breast cancer cell lines. Gene expression analysis using quantitative RT-PCR further confirmed that cell cycle genes controlling G1-S phase transition were largely up-regulated. Changes were not seen in Cyclin B expression levels, which further suggest that cells were arrested before entry into cell division. BCL-2, PPAR-α and PPAR-γ were also up-regulated along with down-regulation of Caspase 3, suggesting molecular iodine induced cell death through activation of a caspase-independent apoptosis pathway. Interestingly, mesenchymal-epithelial transition (MET) occurrence was noticed upon molecular iodine treatment as indicated by sharp increase of GATA3 and E-Cadherin and significant down-regulation of Vimentin in invasive MDA-MB231 cells. Our current study enables us to understand a molecular mechanism controlling tumor cell growth and demonstrates potent cellular effects of molecular iodine on breast cancer cell lines. These results also demonstrate promising effects of molecular iodine for regulation of breast cancer EMT differentiation, which is required for tumor initiation and metastasis. Further studies are underway to determine possible effects of molecular iodine in these breast cancer subtypes using in vitro 3D models. Note: This abstract was not presented at the meeting. Citation Format: Zack Xu, Xin Chen, Noymi Yam, kin Chan, Usha Nagavarapu. Elucidating the mechanism of action of molecular iodine on breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2243. doi:10.1158/1538-7445.AM2017-2243

Increased Electric Conductivity upon I2 Uptake and Gas Sorption in a Pillar-Layered Metal-Organic Framework.

The use of molecular iodine to tune the electrical conductivity in metal-organic frameworks is an effective but seldom investigated strategy. Herein, the single-crystal-to-single-crystal transformation of [Co1.5 (bdc)1.5 (H2 bpz)]⋅DMF⋅4 H2 O (1) to [Co1.5 (bdc)1.5 (H2 bpz)]⋅0.5 I2 ⋅DMF (I2 @1) (H2 bdc=1,4-benzenedicarboxylic acid, H2 bpz=3,3',5,5'-tetramethyl-4,4'-bipyrazole) upon I2 loading caused a three orders of magnitude enhancement in electrical conductivity of the framework. Single-crystal X-ray diffraction revealed that I2 exists as a single molecule embedded in the channels of framework, and the C-H⋅⋅⋅I hydrogen bonds between I2 molecules and phenyl units on the porous surface of the framework were suggested to participate in n→σ* host-guest charge transfer, leading to increased electrical conductivity in I2 @1. Furthermore, 1 displayed moderate adsorption selectivity for CO2 over CH4 and N2 .

Synthetic, Crystallographic, and Computational Studies of Extensively Hydrogen Bonded Bilayers in Thermally Stable Adamantane Hydroperoxides

AbstractThe use of molecular iodine as a heterogeneous catalyst for the peroxidation of adamantan‐2‐one with 30 % H2O2 resulted in an unexpected hydroperoxydiadamantyl peroxide and oxahomoadamantan‐5‐one, in addition to the expected adamantanyl bishydroperoxide. The crystal structures of both the hydroperoxides are reported for the first time. Crystallographic studies revealed that these peroxides are stabilized by extensive intra‐ and intermolecular hydrogen bonds, which are combined in hydrogen‐bonded double layers. These bilayers envelop the hydrophilic interiors consisting of sensitive peroxy groups with the outer surface covered by hydrophobic adamantane groups. The bilayers are held together by weak van der Waals interactions at the layer boundary, which further enhances the thermal stability. Thermal studies demonstrate the remarkable stability of crystalline hydroperoxides at room temperature. A computational study rationalizes the stability of these peroxides. NCI (non‐covalent interactions) plots help to decipher the nature of the interaction between the adamantane units as stabilizing dispersion contacts. QTAIM (quantum theory of atoms in molecules) topological analysis also indicates the presence of strong intermolecular hydrogen bonds along with a number of weak dihydrogen contacts.

Passivation Using Molecular Halides Increases Quantum Dot Solar Cell Performance.

A solution-based passivation scheme is developed featuring the use of molecular iodine and PbS colloidal quantum dots (CQDs). The improved passivation translates into a longer carrier diffusion length in the solid film. This allows thicker solar-cell devices to be built while preserving efficient charge collection, leading to a certified power conversion efficiency of 9.9%, which is a new record in CQD solar cells.

Synthesis of anionic amphiphilic diblock copolymers of poly(styrene) and poly(acrylic acid) by reverse iodine transfer polymerization (RITP) in solution and emulsion

offer the appealing prospect of synthesizing these amphiphilic block copolymers. However, there are numerous drawbacks arising from the use of each technique in terms of the high cost of the control agents as in NMP and RAFT, the cumbersome removal of the catalyst in the ATRP catalytic system and the instability problems of the transfer agents requiring thereby special precautions during storage. In the respect of overcoming the problems posed by the common CRP techniques, great interest is involved in adopting and developing the innovative CRP method called Reverse Iodine Transfer Polymerization (RITP) 7-8 which was developed by our group. This method comprises a degenerative chain transfer mechanism and its simplicity rests on the use of molecular iodine (or its precursors such as sodium iodide, NaI) 9-10 for the in situ generation of transfer agents. Herein, we report the synthesis of amphiphilic diblock copolymers of poly(styrene), (PS) and poly(acrylic acid) (PAA) from the easy cleavable tert-butyl acrylate precursor, by reverse iodine transfer polymerisation (RITP) in solution and emulsion. Experimental Materials. Tert-butyl acrylate (tBA, Aldrich, 98%) was extracted three times with 5% aqueous NaOH and then washed with distilled water. After drying over CaCl2 and filtering off the drying agent, the monomer was distilled under reduced pressure. Styrene (Acros, 99%) and toluene (BDH, 99%) were distilled under reduced pressure before use. 2,2'- Azobis(isobutyronitrile) (AIBN, Fluka, 98 %) was purified by recrystallization in methanol. Iodine (I2, Aldrich, 99.8%), trifluroacetic acid (TFA, Aldrich, 99%), dichloromethane (DCM) (Fluka), potassium persulfate (KPS, Aldrich, 99%), sodium 1-hexadecanesulfonate (M= 328.49 g.mol -1 , Lancaster, 99%), and Mersolat H40 (Lanxess, 40% aqueous solution) were used as received. Water was deionized by passing it through columns packed with ion exchange resins. Instrumentation. The samples were characterized by 1

Molecular-iodine-catalyzed aerobic photooxidative C–C bond formation between tertiary amines and carbon nucleophiles

This paper reports a useful method for molecular-iodine-catalyzed aerobic photooxidative C–C bond formation between tertiary amines and carbon nucleophiles. This reaction provides a practical method for C–C bond formation through the use of molecular iodine, harmless visible light irradiation, and molecular oxygen as the terminal oxidant.

Organic Domino Reactions Catalyzed by Molecular Iodine

Molecular iodine has established itself as an efficient catalyst in organic synthesis to attain several organic transformations. Domino reactions involve the synthesis of a target molecule in a single step where three or more components are reacting simultaneously. Thus these types of domino reactions are carried out in the presence of iodine as a catalyst. They have more significance and are fascinating in organic synthesis. The use of molecular iodine as catalyst in various domino reactions along with the recent patents is discussed in this review. Keywords: Biginelli reaction, domino reaction, imino-Diels-Alder (Povarov) reaction, Mannich reaction, Michael reaction and molecular iodine.

ChemInform Abstract: Molecular Iodine: Recent Application in Heterocyclic Synthesis

AbstractReview: 132 refs.

Molecular Iodine: Recent Application in Heterocyclic Synthesis

In this review, the use of molecular iodine as a catalyst in the synthesis of heterocyclic compounds is presented and reviewed. In recent years, the use of molecular iodine in organic chemistry has received considerable attention because the chemical (a) is inexpensive and readily available, (b) is less toxic than alternatives, (c) has an easy workup method, and (d) is a moisture-stable, mild Lewis acid. Many of the reactions using iodine are associated with mild conditions, greater stero- and regioselectivities, short reaction times, and simplicity in their operation. Keywords: Molecular iodine, catalyst, heterocyclic compounds, synthesis, hormones, antibiotics, alkaloids, herbicides, corrosion inhibitors, antiaging drugs, sensitizers, stabilizing agents, electropositive metallic halogen, Chilesn saltpeter, Courtois

Molecular Iodine: A Versatile Catalyst for the Synthesis of 4-Aryl-3-methyl-1-phenyl-1H-benzo[h]pyrazolo[3,4-b]quinoline-5,10-diones in Water

Water has therefore become an attractive medium for many organic reactions, not only for the advantages con-cerning the avoidance of expensive, catalysts and solvents, but also for some unique reactivity and selectivity. In recent years, the use of molecular iodine in organic synthesis has received considerable attention due to powerful catalytic activity for various organic transformations.

Molecular Iodine-Mediated Cyclization of Tethered Heteroatom-Containing Alkenyl or Alkynyl Systems

Molecular iodine has established itself as a readily available and easy-to-handle electrophilic and oxidizing reagent used in various organic transformations. In this review attention is focused on the use of molecular iodine in promoting cyclization (iodocyclization and cyclodehydroiodination) of tethered heteroatom-containing alkenyl or alkynyl systems.

Highly Selective Catalytic Friedel – Crafts Acylation of Activated Aromatic Compounds Using the I2.DMF Complex as Catalyst

A novel method has been developped for synthesizing aryl ketones by means of I2-DMF mediated Friedel – Crafts acylation of aromatic substrates. The reaction is applicable to activated aromatic compounds. The present process is carried out under conditions involving minimal wastes and energy-consumption as compared to the use of molecular iodine. Keywords: I2-DMF, AlCI3-DMF, anisole, aromatic substrates, heteroaromatic substrates, Friedel-Crafts reaction

Efficient Baeyer–Villiger Oxidation of Ketones using Molecular Iodine/H2O2 as Heterogeneous Catalytic System

The use of molecular iodine as a catalyst for the oxidation of ketones using hydrogen peroxide in the presence of acetic acid at room temperature is reported.

Deoxygenative Allylation of Benzyl Acetates and Cinnamyl Alcohols Catalyzed by Molecular Iodine

Abstract Benzyl acetates undergo smooth deoxygenative allylation with allyltrimethylsilane in the presence of 10 mol % of molecular iodine under mild conditions to afford the corresponding allyl derivatives in excellent yields and with high selectivity. Cinnamyl alcohols also react readily with allylsilane under similar conditions. The use of molecular iodine makes this method quite simple, more convenient and cost effective.

Living Radical ab Initio Emulsion Polymerization of n-Butyl Acrylate by Reverse Iodine Transfer Polymerization (RITP): Use of Persulfate as Both Initiator and Oxidant

Reverse iodine transfer polymerization (RITP) represents a new straightforward way to prepare controlled macromolecular architectures and relies on the use of molecular iodine (I2) as control agent. In this work, a one-step ab initio emulsion polymerization of n-butyl acrylate in the presence of molecular iodine has been successfully performed with potassium persulfate playing the dual role of radical initiator and oxidant. The polymerization was initiated by potassium persulfate at T = 85 °C with sodium 1-hexadecanesulfonate as surfactant, yielding a stable and uncolored latex. The hydrolytically disproportionated iodine was regenerated by potassium persulfate as oxidant (also serving as radical initiator), leading to the expected targeted molecular weight (e.g., butyl acrylate conversion = 99%, Mn,theoretical = 10 100 g mol-1, Mn,SEC = 9800 g mol-1, Mw/Mn = 1.8, particle diameter dp = 83 nm with a monomodal particle size distribution). The use of potassium persulfate as both radical initiator and oxidant offers a convenient way to overcome the upward deviation of the molecular weights due to hydrolytic disproportionation of iodine, which was a limitation for the implementation of the RITP process in dispersed aqueous media. The persulfate is able to regenerate iodine, and hence the molecular weight of the polymer chains can be accurately controlled by the concentration of iodine. Furthermore, a poly(butyl acrylate)-b-poly(butyl acrylate-co-styrene) block copolymer was synthesized in seeded emulsion polymerization, proving the living character of the polymerization.

Iodine-promoted Prins-cyclization of ketones — A facile synthesis of spirocyclic-4-iodo-tetrahydropyrans and 5,6-dihydro-2H-pyrans

Homoallylic and homopropargylic alcohols undergo smooth coupling with ketones in the presence of molecular iodine at ambient temperature to produce spirocyclic-4-iodotetrahydropyrans and 5,6-dihydro-2H-pyrans, respectively, in high yields in a short reaction time with high selectivity. The use of molecular iodine makes this procedure quite simple, more convenient, and cost-effective.Key words: Prins-cyclization, iodine, homopropargylic alcohol, spirocyclic-4-iodopyrans.

Synthetic Use of Molecular Iodine for Organic Synthesis.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Synthetic Use of Molecular Iodine for Organic Synthesis

The synthetic use of molecular iodine is described. Iodine is a universal oxidizing agent, especially for the oxidation of alcohols and aldehydes to esters, nitriles and amides. Further applications are the introduction of protecting groups, deprotection, iodocyclization, C-C bond formation, and formation of heterocycles.