- Synthesis, characterization and initial evaluation of 5-nitro-1- (trifluoromethyl)-3H-1λ3,2-benziodaoxol-3-one
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The synthesis of 5-nitro-1-(trifluoromethyl)-3H-1λ3,2- benziodaoxol-3-one (3), a hypervalent-iodine-based electrophilic trifluoromethylating reagent, is described. Whereas considerations based on cyclic voltammetry and X-ray structural properties would predict an inferior reactivity when compared to the non-nitrated derivative 2, 19F NMR kinetic studies showed that this new derivative is almost one order of magnitude more reactive. Furthermore, differential scanning calorimetry measurements indicated that, in addition, it is also safer to handle.
- Santschi, Nico,Sarott, Roman C.,Otth, Elisabeth,Kissner, Reinhard,Togni, Antonio
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- Synthesis of isocoumarins via Pd/C-mediated reactions of o-iodobenzoic acid with terminal alkynes
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The coupling reaction of o-iodobenzoic acid with terminal alkynes by using a catalyst system of 10% Pd/C-Et3N-CuI-PPh3 has been studied in a variety of solvents. 3-Substituted isocoumarins were formed in good yields and with good reg
- Subramanian, Venkataraman,Batchu, Venkateswara Rao,Barange, Deepak,Pal, Manojit
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- Singlet Oxygen Generation from a Water-Soluble Hypervalent Iodine(V) Reagent AIBX and H2O2: An Access to Artemisinin
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Herein, we report an efficient method for the chemical generation of 1O2 by treatment of H2O2 with AIBX, a highly water-soluble, bench-stable, recyclable hypervalent iodine(V) reagent developed by our group. The generation of 1O2 was confirmed by the following results: (1) capture of 1O2 with the sodium salt of anthracene-9,10-bis(ethanesulfonate) produced the corresponding endoperoxide and (2) TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) produced by the oxidation of 2,2,6,6-tetramethylpiperidine with 1O2 generated using the AIBX/H2O2 system was detected by electron spin resonance spectroscopy. To illustrate the potential utility of this method for organic synthesis, we used the AIBX/H2O2 system to perform typical reactions of 1O2: [2 + 2]/[4 + 2] cycloadditions, Schenck ene reactions, and heteroatom oxidation reactions, which afforded the corresponding products in high yields. Moreover, we used the method to synthesize the antimalarial drug artemisinin. Finally, we demonstrated that AIBX could be regenerated after the reaction by means of a workup involving extraction and removal of water to obtain a precursor of AIBX, which could then be re-oxidized.
- Hu, Ze-Nan,Shen, Hui-Jie,Zhang, Chi
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supporting information
(2021/06/21)
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- One-Pot Synthesis and Conformational Analysis of Six-Membered Cyclic Iodonium Salts
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Two one-pot procedures for the construction of carbon-bridged diaryliodonium triflates and tetrafluoroborates are described. Strong Br?nsted acids enable the effective Friedel-Crafts alkylation with diversely substituted o-iodobenzyl alcohol derivatives, providing diphenylmethane scaffolds, which are subsequently oxidized and cyclized to the corresponding dibenzo[b,e]iodininium salts. Based on NMR investigations and density functional theory (DFT) calculations, we could verify the so-far-undescribed existence of two stable isomers in cyclic iodonium salts substituted with aliphatic side chains in the carbon bridge.
- Caspers, Lucien D.,Spils, Julian,Damrath, Mattis,Lork, Enno,Nachtsheim, Boris J.
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p. 9161 - 9178
(2020/08/14)
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- One-Pot C-H Arylation/Lactamization Cascade Reaction of Free Benzylamines
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An efficient method has been developed for the synthesis of seven-membered biaryl lactams involving Pd-catalyzed, native amine-directed, ortho-arylation of benzylamines followed by in situ lactamization. This cascade sequence is enabled by the use of 2-iodobenzoates, which facilitates C-H arylation from the free amine under conditions that typically require an improved directing group approach. This reaction is characterized by a broad substrate scope with good functional group tolerance. The need for an ester versus carboxylic acid-functionalized coupling partner is also explored, as is the potential for synthesizing eight-membered biaryl lactams. Various applications are also investigated, including access to the aza-brassinolide core.
- Chand-Thakuri, Pratibha,Landge, Vinod G.,Kapoor, Mohit,Young, Michael C.
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p. 6626 - 6644
(2020/07/14)
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- [Bis(trifluoroacetoxy)iodo]p-nitrobenzene and [bis(trifluoroacetoxy)iodo]pentafluorobenzene as lead reagents for the direct ring contraction of lactams to pyrrolidines
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Two 3-iodanes, namely [bis(trifluoroacetoxy)iodo]p-nitrobenzene and [bis(trifluoroacetoxy)iodo]pentafluorobenzene, were used to effect the direct ring-contraction of lactams to pyrrolidines. Intense reaction optimization was necessary but only
- Aubert-Nicol, Samuel,Heinrich, Nora,Lessard, Jean,Spino, Claude
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p. 484 - 501
(2019/08/01)
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- Oxidation of secondary alcohols using solid-supported hypervalent iodine catalysts
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It is shown how secondary alcohols are oxidized to provide the corresponding ketones by use of Oxone and solid-supported hypervalent iodine catalysts. Under experimentally simple conditions with acetonitrile at elevated temperatures, excellent conversions were achieved with low catalyst loadings (0.2-5 mol%) when employing the conjugates 5 and 6 derived from IBX and IBS. The catalysts are broadly applicable to a range of alcohol substrates. Of primary importance with respect to sustainability issues, the metal-free catalysts are easily removed from the reaction mixture through filtration, and they can be re-used in oxidation processes for multiple times, without loss of catalytic activity.
- Ballaschk, Frederic,Kirsch, Stefan F.
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supporting information
p. 5896 - 5903
(2019/11/11)
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- Regioselectivity Influences in Platinum-Catalyzed Intramolecular Alkyne O-H and N-H Additions
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The steric and electronic drivers of regioselectivity in platinum-catalyzed intramolecular hydroalkoxylation are elucidated. A branch point is found that divides the process between 5-exo and 6-endo selective processes, and enol ethers can be accessed in good yields for both oxygen heterocycles. The main influence arises from an electronic effect, where the alkyne substituent induces a polarization of the alkyne that leads to preferential heteroatom attack at the more electron-deficient carbon. The electronic effects are studied in other contexts, including hydroacyloxylation and hydroamination, and similar trends in directionality are predominant although not uniformly observed.
- Costello, Jeff P.,Ferreira, Eric M.
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supporting information
p. 9934 - 9939
(2019/12/24)
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- Copper-catalyzed domino reaction of carbodiimides and benzoic acid derivatives for the synthesis of quinazolinediones
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Quinazolinediones were obtained from 2-iodobenzoic acids and carbodiimide derivatives under mild reaction conditions via a copper-catalyzed domino reaction. The absence of an external base was essential to avoid the generation of amide by-products. Both alkyl- and aryl-substituted carbodiimides gave the corresponding quinazolinediones. However, the use of aryl-substituted carbodiimides resulted in low yields due to an undesired elimination process.
- Duangjan, Chanikan,Rukachaisirikul, Vatcharin,Saithong, Saowanit,Kaeobamrung, Juthanat
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supporting information
p. 3537 - 3540
(2018/08/29)
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- 2-Iodo-N-isopropyl-5-methoxybenzamide as a highly reactive and environmentally benign catalyst for alcohol oxidation
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Several N-isopropyliodobenzamides were evaluated as catalysts for the oxidation of benzhydrol to benzophenone in the presence of Oxone (2KHSO5·KHSO4·K2SO4) as a co-oxidant at room temperature. A study on the substituent effect of the benzene ring of N-isopropyl-2-iodobenzamide on the oxidation revealed that its reactivity increased in the following order of substitution: 5-NO2 2Me, 3-OMe 5-OAc 5-Cl H, 4-OMe 5-Me 5-OMe. The oxidation of various benzylic and aliphatic alcohols using a catalytic amount of the most reactive 5-methoxy derivative successfully resulted in moderate to excellent yields of the corresponding carbonyl compounds. The high reactivity of the 5-methoxy derivative at room temperature is a result of the rapid generation of the pentavalent species from the trivalent species during the reaction. 5-Methoxy-2-iodobenzamide would be an efficient and environmentally benign catalyst for the oxidation of alcohols, especially benzylic alcohols.
- Yakura, Takayuki,Fujiwara, Tomoya,Yamada, Akihiro,Nambu, Hisanori
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supporting information
p. 971 - 978
(2019/11/11)
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- Palladium-Catalyzed, Norbornene-Mediated, ortho-Amination ipso-Amidation: Sequential C-N Bond Formation
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A palladium-catalyzed, norbornene-mediated ortho- and ipso-C-N bond-forming Catellani reaction is reported. This reaction proceeds through a sequential intermolecular amination followed by intramolecular cyclization of a tethered amide. The products, ortho-aminated dihydroquinolinones, were generated in moderate to good yields and are present in bioactive molecules. This work highlights the challenge of competing intra- vs intermolecular palladium-catalyzed processes.
- Whyte, Andrew,Olson, Maxwell E.,Lautens, Mark
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supporting information
p. 345 - 348
(2018/01/27)
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- A photoredox-neutral Smiles rearrangement of 2-aryloxybenzoic acids
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We report on the use of visible light photoredox catalysis for the radical Smiles rearrangement of 2-aryloxybenzoic acids to obtain aryl salicylates. The method is free of noble metals and operationally simple and the reaction can be run under mild batch or flow conditions. Being a redox neutral process, no stoichiometric oxidants or reductants are needed.
- Gonzalez-Gomez, Jose C.,Ramirez, Nieves P.,Lana-Villarreal, Teresa,Bonete, Pedro
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supporting information
p. 9680 - 9684
(2017/11/30)
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- Synthesis of DIBAC analogues with excellent SPAAC rate constants
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In search for increased reactivity in strain-promoted azide alkyne cycloadditions (SPAAC), the synthesis of new and more reactive cyclooctynes is of pivotal importance. To identify cyclooctynes with enhanced reactivity, without loss of stability, the synthesis and kinetic analysis of new dibenzoazacyclooctyne (DIBAC) analogues were conducted. Starting from iodobenzyl alcohol analogues and ortho-ethynylaniline various substituted dihydrodibenzo[b,f]azocines were produced. Subsequent bromination and elimination proved to be difficult depending on the aromatic substitution pattern, yielding chloro-, bromo-, and methoxy-substituted DIBACs in moderate yield. In the elimination reaction towards nitro- and Br,Cl-DIBAC, the corresponding cyclooctene was obtained instead of the cyclooctyne. Additionally, a dimethoxy-substituted DIBAC analogue was prepared following an alternative route involving light-induced deprotection of a cyclopropenone derivative. In total, four DIBAC analogues were successfully prepared showing excellent rate constants in the SPAAC reaction ranging from 0.45 to 0.9 M-1 s -1, which makes them comparable to the fastest cyclooctynes currently known. This journal is the Partner Organisations 2014.
- Debets, Marjoke F.,Prins, Jasper S.,Merkx, Donny,Van Berkel, Sander S.,Van Delft, Floris L.,Van Hest, Jan C. M.,Rutjes, Floris P. J. T.
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supporting information
p. 5031 - 5037
(2014/07/07)
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- SUBSTITUTED AZADIBENZOCYCLOOCTYNE COMPOUNDS AND THEIR USE IN METAL-FREE CLICK REACTIONS
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The invention relates to a substituted azadibenzocyclooctyne compound according to Formula (5): The invention also relates to a conjugate wherein a substituted azadibenzocyclooctyne according to the invention is conjugated to a label, and to the use of these conjugates for bioorthogonal labeling, imaging or modification of a target molecule, e.g. surface modification. The invention further relates to a method for the modification of a target molecule, wherein a conjugate according to the invention is reacted with a compound comprising a 1,3-dipole or a 1,3-(hetero)diene.
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Page/Page column 28-29
(2014/12/12)
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- Intriguing substituent effect in modified Hoveyda-Grubbs metathesis catalysts incorporating a chelating iodo-benzylidene ligand
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A series of modified Hoveyda-Grubbs catalysts incorporating a chelating iodo-benzylidene ligand were prepared and characterized. The presence of electron-withdrawing ring substituents in the para position to the iodide was found to decrease the catalytic activity, revealing that dissociation of the Ru...I-Ar bond is not the rate-determining step.
- Barbasiewicz, Michal,Blocki, Krzysztof,Malinska, Maura,Pawlowski, Robert
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supporting information
p. 355 - 358
(2013/02/22)
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- Facile oxidation of alcohols to aldehydes or ketones with 1-acetoxy-5-nitro-1,2-benziodoxole-3(1 H)-one
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Various benzylic alcohols and aliphatic secondary alcohols were smoothly oxidized to the corresponding aromatic aldehydes, aromatic ketones, and aliphatic ketones, respectively, with the novel 1-acetoxy-5-nitro-1,2- benziodoxole-3(1H)-one (ANBX) alone, a trivalent iodine prepared from the oxidation of 2-iodo-5-nitrobenzoic acid with MCPBA. The present reaction is the first effective method for the oxidation of alcohols with a trivalent iodine alone under mild reaction conditions. Georg Thieme Verlag Stuttgart New York.
- Iinuma, Masataka,Moriyama, Katsuhiko,Togo, Hideo
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p. 1707 - 1711
(2013/09/02)
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- Copper(II)chloride-mediated cyclization reaction of N-alkoxy- orthoalkynylbenzamides
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A regioselective intramolecular cyclization/halogenation reaction of N-alkoxy-o-alkynylbenzamides with CuCl2/NCS was developed. The corresponding 3-(chloromethylene)isobenzofuran-1-ones were exclusively obtained via 5-exo-dig cyclization in moderate to excellent yields within 0.5-1 h. This approach has been successfully used to synthesize a biaryl compound by the Suzuki-Miyaura reaction.
- Jithunsa, Manita,Ueda, Masafumi,Miyata, Okiko
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supporting information; experimental part
p. 518 - 521
(2011/04/16)
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- Design, synthesis, structure, and dehydrogenation reactivity of a water soluble o-iodoxybenzoic acid derivative bearing a trimethylammonium group
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5-Trimethylammonio-1, 3-dioxo-1, 3-dihydro-1λ5-benzo[d][1, 2]iodoxol-1-ol anion (AIBX 1a), an o-iodoxybenzoic acid (IBX) derivative having the trimethylammonium moiety on its phenyl ring, possesses very good solubility in water and distinct oxidative properties from IBX, which is demonstrated in the oxidation of various β-keto esters to the corresponding dehydrogenated products using water as cosolvent. The regeneration of AIBX 1a can be easily realized from the reaction mixture due to its good water solubility.2011 American Chemical Society.
- Cui, Li-Qian,Dong, Zhi-Lei,Liu, Kai,Zhang, Chi
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supporting information; experimental part
p. 6488 - 6491
(2012/02/02)
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- 2-iodoxybenzenesulfonic acid as an extremely active catalyst for the selective oxidation of alcohols to aldehydes, ketones, carboxylic acids, and enones with oxone
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Electron-donating group-substituted 2-iodoxybenzoic acids (IBXs) such as5-Me-IBX (1g), 5-MeO-IBX (1h), and 4,5-Me2-IBX were superior to IBX 1a as catalysts for the oxidation of alcohols with Oxone (a trad emark of DuPont) under nonaqueous conditions, although Oxone was almost insoluble in most organic solvents. The catalytic oxidation proceeded more rapidly and cleanly in nitromethane. Furthermore, 2-iodoxybenzenesulfonic acid (IBS, 6a) was much more active than modified IBXs. Thus, we established a highly efficient and selective method for the oxidation of primary and secondary alcohols to carbonyl compounds such as aldehydes, carboxylic acids, and ketones with Oxone in nonaqueous nitromethane, acetonitrile, or ethyl acetate in the presence of 0.05-5molpercentof 6a, which was generated in situ from 2-iodobenzenesulfonic acid (7a) or its sodium salt. Cycloalkanones could be further oxidized to α,β- cycloalkenones or lactones by controlling the amounts of Oxone under the same conditions as above. When Oxone was used under nonaqueous conditions, Oxone wastes could be removed by simple filtration. Based on theoretical calculations, we considered that the relatively ionic character of the intramolecular hypervalent iodine-OSO2 bond of IBS might lower the twisting barrier of the alkoxyperiodinane intermediate 16.
- Uyanik, Muhammet,Akakura, Matsujiro,Ishihara, Kazuaki
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supporting information; experimental part
p. 251 - 262
(2009/06/28)
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- Synthesis of new crosslinkable co-polymers containing a push-pull zinc porphyrin for non-linear optical applications
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In this paper, the synthesis of a crosslinkable co-polymer containing new push-pull arylethynyl zinc porphyrins is described. The synthesis of porphyrin chromophores, analogous to Therien's porphyrin (J. Am. Chem. Soc. 1996, 118, 1497-1503) functionalized
- Monnereau, Cyrille,Blart, Errol,Montembault, Véronique,Fontaine, Laurent,Odobel, Fabrice
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p. 10113 - 10121
(2007/10/03)
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- Activated iododerivatives for the treatment of cancer and AIDS
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A series of activated iodo-benzamide derivatives are described as antineoplastic and antiviral drug compounds. The compounds generally possess a chelating group, a thiol trapping group and an activating group. The presumptive mechanism of action in preven
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- Palladium-catalysed heteroannulation with terminal alkynes: A highly regio- and stereoselective synthesis of (Z)-3-aryl(alkyl)idene isoindolin-1- ones
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A highly regio- and stereoselective method for the synthesis of (Z)-3- aryl(alkyl)idene isoindolin-1-ones through palladium-copper catalysis is described. 2-Iodobenzamide 1 and its substituted derivatives 2-10 were reacted with terminal alkynes 11-19 in the presence of (PPh3)2PdCl2, CuI, and Et3N in DMF mostly at 80°C for 16 h to yield the 2-alkynyl substituted benzamides 20-38, 40-45, 77 which could then be cyclised with NaOEt in EtOH to the 3-aryl(alkyl)idene isoindolin-1-ones 46-49, 51, 53-55, 57, 59-71, 73 and 75. In certain cases, the isoindolin-1-ones 50, 52, 56 and 58 could be directly obtained by the palladium-catalysed reactions. (C) 2000 Elsevier Science Ltd.
- Kundu, Nitya G.,Khan, M. Wahab
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p. 4777 - 4792
(2007/10/03)
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- 13C NMR Study of 2-Iodoso- and 2-Iodoxy-benzoic Acids and Their Sodium Salts
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The 13C NMR spectra for selected 2-iodosobenzoic acids, their sodium salts and the sodium salts of the corresponding iodoxybenzoic acids were measured and carbon assignments made using 2D and NOE experiments and relaxation times.Iodoso and iodoxy groups deshielded the ipso-carbon in these compounds by approximately 25 and 55 ppm, repectively, relative to the corresponding iodo compounds.The 13C NMR spectrs of the 2-iodosobenzoate anions were almost identical with those of the corresponding free acids, both possessing cyclic structures.The iodoxybenzoic acids are either insoluble in, or oxidize, suitable NMR solvents (i.e.DMSO-d6, DMF-d7).The cyclic structure postulated for iodoxybenzoate anions is supported by their 13C chemical shifts.----Key words 13C NMR 2-Iodosobenzoic acids 2-Iodoxybenzoic acids Sodium 2-iodosobenzoates Sodium 2-iodoxybenzoates
- Katritzky, Alan R.,Duell, Bradley L.,Gallos, John K.
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p. 1007 - 1011
(2007/10/02)
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