- The crystal structure of the Dess-Martin periodinane
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We report the elusive X-ray structure of the Dess-Martin periodinane (DMP), a hypervalent iodine reagent popular amongst synthetic chemists. In the solid state, the highly crystalline compound forms an intricate coordination polymer held together by intermolecular halogen and hydrogen bonds.
- Schroeckeneder, Albert,Stichnoth, Desiree,Mayer, Peter,Trauner, Dirk
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Read Online
- Process for preparing Dess-Martin reagent through solid superacid catalysis
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The invention belongs to the technical field of organic synthesis, and discloses a process for preparing a Dess-Martin reagent through solid superacid catalysis. The process comprises the following steps of: S1, oxidation reaction, specifically, mixing potassium bromate and tap water, adding solid superacid HERD-Cat-1, stirring and heating the materials to 40-90 DEG C; adding o-iodobenzoic acid in batches, reacting for 1-8 hours at the temperature after addition of the o-iodobenzoic acid, performing cooling, and then centrifugally washing a product with water and washing with an organic solvent to obtain an IBX wet product; S2, acetylation reaction, specifically, adding the IBX wet product into an organic solvent, performing dissolving and filtering, recovering solid superacid HERD-Cat-1, adding a catalyst and acetic anhydride, heating to 40-80 DEG C, performing a reaction, performing cooling and crystallizing, and performing centrifugation and drying to obtain the Dess-Martin reagent. After the solid superacid is used for catalysis, generation of a large amount of waste acid is avoided, and meanwhile the purity of IBX is high. The process has the advantages of short reaction steps, high chemical purity, simplicity in operation, low cost, high production safety, environmental friendliness and the like, and is suitable for industrial production.
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Paragraph 0014; 0021-0022; 0024-0025; 0027-0028; 0030-0031
(2021/07/31)
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- SCALEABLE PREPARATION OF POLYKETIDES
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Disclosed herein, inter alia, are methods of making polyketide compounds.
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Paragraph 0315
(2021/02/12)
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- Preparation method of β - carotene with high total trans content
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The invention provides a preparation method of β - carotene with a high total trans content. Starting from the vitamin A derivative, C20 phosphine salt is obtained through reaction with triphenylphosphine, and the C20 phosphine salt is subjected to condensation reaction under the action IBX high iodine compound and base to obtain β - carotene containing cis-trans, and then the β - carotene with high trans content is obtained under the action of a transition metal loading catalyst. The method avoids the use of a strong oxidizing agent in the traditional process, is environmentally friendly and can reduce the peroxidation of β - carotene, so that the reaction yield is increased, and the transition metal catalyst enables the obtained β - carotene content to be full. Trans increase.
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Paragraph 0047-0049
(2021/09/01)
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- METHOD FOR PRODUCING HYPERVALENT IODINE COMPOUND USING HYPOCHLORITE
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PROBLEM TO BE SOLVED: To provide a method for producing a hypervalent iodine compound as a 2-iodobenzoic acid derivative that is safer and more convenient than the conventional method. SOLUTION: The method includes mixing 2-iodobenzoic acid as a starting material with hypochlorite or hypochlorite aqueous solution. During the reaction, depending on whether acetic acid or acetic anhydride is present or not in the mixture, IBA, IBA-OAc, IBX can be produced separately and selectively. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPO&INPIT
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Paragraph 0033-0035
(2020/10/03)
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- Method for preparing 2-iodoxybenzoic acid
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The invention relates to a method for preparing 2-iodoxybenzoic acid, and belongs to the technical field of synthesis of rings containing a halogen atom as a heterocyclic atom. The method comprises the following steps: adding an oxidant to 2-iodobenzoic acid used as a raw material, carrying out a reaction in an acidic solution at 50-120 DEG C for 1-6 h, and purifying the obtained reaction productto obtain the 2-iodoxybenzoic acid. The method has the advantages of small toxicity, mild technologic conditions, economical and cheap property and suitableness for industrialization when applied to the synthesis of a catalyst.
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Paragraph 0019-0024; 0031-0035; 0063-0066
(2019/02/13)
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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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- Preparation method of oxidizing agent IBX
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The invention discloses a preparation method of 2-iodoxy benzoic acid. The preparation method includes: 2-iodobenzoic acid, potassium hydrogen sulfate and the like are used as the raw materials to prepare the product 2-iodoxy benzoic acid through one-step reaction. The preparation method has the advantages that the preparation method is simple and stable in process operation, easy in product separation and high in yield, and product purity reaches 99.5% or above; the raw materials are cheap and easy to obtain, the production cost of existing biological, medicinal and chemical intermediates islowered greatly, and industrial large-scale production is benefited.
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Paragraph 0023; 0024; 0026; 0028; 0030; 0033; 0034; 0039
(2019/01/14)
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- Preparation method of DMP (Dess-Martin periodinane)
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The invention discloses a preparation method of a DMP (Dess-Martin periodinane). The target product DMP is obtained through two steps of reactions with 2-iodobenzoic acid, potassium hydrogen persulfate, glacial acetic acid, acetic anhydride and the like as raw materials. The process is convenient and stable, the product is easy to separate and high in yield, the method is environmentally friendly,the comprehensive yield is 82% or above, the raw materials are cheap and easy to obtain, and industrial mass production is facilitated.
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Paragraph 0034-0037; 0040; 0043; 0045-0053
(2019/01/13)
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- Dynamic kinetic resolution of bis-aryl succinic anhydrides: Enantioselective synthesis of densely functionalised γ-butyrolactones
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The efficient Dynamic Kinetic Resolution (DKR) of disubstituted anhydrides has been shown to be possible for the first time. Using an ad hoc designed organocatalyst and an enantio- and diastereoselective cycloaddition process with aldehydes, stereochemically complex γ-butyrolactone derivatives can be obtained-with control over three contiguous stereocentres, one of which is all carbon quaternary.
- Claveau, Romain,Twamley, Brendan,Connon, Stephen J.
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supporting information
p. 3231 - 3234
(2018/04/05)
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- Palladium-Catalyzed Direct β-C?H Arylation of Ketones with Arylboronic Acids in Water
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A palladium-catalyzed direct β-C?H arylation of ketones was developed under mild conditions in water, featuring commercially available arylboronic acids as nucleophilic aryl sources and o-iodoxybenzoic acid as the oxidant. The method provides a concise route to access β-arylated ketones. Preliminary studies indicated that direct asymmetric β-C?H arylation of ketones could be achieved by this strategy. (Figure presented.).
- Hu, Xiaoyun,Yang, Xiaobo,Dai, Xi-Jie,Li, Chao-Jun
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supporting information
p. 2402 - 2406
(2017/07/22)
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- Regulation of liver X receptor target genes by 22-functionalized oxysterols. Synthesis, in silico and in vitro evaluations
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The endogenous oxysterol 22(R)-hydroxycholesterol (22RHC, 1) is an LXR agonist which upregulates genes of critical involvement in human cholesterol- and lipid metabolism. In contrast, its synthetic epimer 22(S)-hydroxycholesterol (22SHC, 8) has shown specific antagonistic effects in recent studies, avoiding unwanted side effects provided by potent LXR agonists. In terms of LXR modulation, the aim of this study was to compare 22SHC (8), 22RHC (1) and synthesized ligands with keto- and amide functionality in the 22nd position of the cholesterol scaffold. 22SHC (8) and 22RHC (1) performed as expected while 22-ketocholesterol (22KC, 10) revealed an attractive in vitro profile for further investigation in terms of anti-atherosclerotic properties as selective upregulation of the ATP-binding cassette transporter ABCA1 was observed. A new synthesized amide derivate, Fernholtz cyclohexylamide (13) was shown to reduce lipogenesis in a dose-responsive manner and abolish the effect of the potent LXR agonist T0901317 when administered simultaneously.
- Viktorsson, Elvar ?rn,Gabrielsen, Mari,Kumarachandran, Nugalya,Sylte, Ingebrigt,Rongved, P?l,?strand, Ove Alexander H?gmoen,Kase, Eili Tranheim
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supporting information
p. 119 - 127
(2017/01/13)
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- 2-Iodoxybenzoic Acid Tosylates: the Alternative to Dess–Martin Periodinane Oxidizing Reagents
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Two powerful hypervalent iodine(V) oxidants, DMP-OTs (1-tosyloxy-1,1-diacetoxy-1H-1λ5-benzo[d][1,2]iodoxol-3-one) and IBX-OTs (1-tosyloxy-1-oxo-1H-1λ5-benzo[d][1,2]iodoxol-3-one) show high reactivity in the oxidation of structurally complex primary and secondary alcohols, which are highly functionalized polyketide or terpene fragments or steroids. The yields of the corresponding carbonyl compounds are even higher for the protocol that uses pyridine as additive. The oxidations proceed very rapidly at room temperature leaving the protective groups and π-systems intact and affording the corresponding carbonyl compounds in good to excellent yields. Moreover, IBX-OTs is an efficient reagent for the oxidative dehydrogenation of steroidal alcohols to the corresponding enones. (Figure presented.).
- Yusubov, Mekhman S.,Postnikov, Pavel S.,Yusubova, Roza Ya.,Yoshimura, Akira,Jürjens, Gerrit,Kirschning, Andreas,Zhdankin, Viktor V.
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p. 3207 - 3216
(2017/09/11)
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- Preparation method of N-Boc biphenyl alaninal
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The invention discloses a preparation method of N-Boc-biphenyl alaninal, and the preparation method comprises the following steps: the N-Boc-biphenyl alaninal can be obtained by oxidation reaction of N-Boc-biphenyl alaninol and 2-iodoxybenzoic acid in an organic solvent. The method has the advantages of simple operation, high yield, high purity, low cost and little pollution, and is suitable for industrial production.
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Paragraph 0033-0034
(2017/08/28)
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- An efficient synthesis of iminoquinones by a chemoselective domino ortho-hydroxylation/oxidation/imidation sequence of 2-aminoaryl ketones
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An efficient chemoselective domino oxidative homocoupling of 2-aminoaryl ketones in the presence of 2-iodoxybenzoic acid (IBX) for the synthesis of iminoquinone has been developed. The domino reaction proceeds via three consecutive steps, such as domino ortho-hydroxylation of 2-aminoaryl ketones, oxidation of a phenol derivative to benzoquinone and dimerization through imine formation to yield iminoquinone. Importantly, this reaction allows the recycling of the oxidant IBX by recovering the by-product iodosobenzoic acid (IBA) and oxidizing it back to IBX. A four step domino strategy for the synthesis of iminoquinone through in situ generation of 2-amino benzophenone from (2-amino phenyl)(phenyl)methanol was also developed.
- Chandrasekar, Selvaraj,Sekar, Govidasamy
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p. 3053 - 3060
(2016/03/19)
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- IBX-mediated oxidation of unactivated cyclic amines: application in highly diastereoselective oxidative Ugi-type and aza-Friedel-Crafts reactions
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The first o-iodoxybenzoic acid (IBX) mediated oxidation of unactivated amines to imines is described. A range of meso-pyrrolidines were shown to be suitable substrates. The chemical space was further explored with one-pot oxidative Ugi-type and aza-Friedel-Crafts reactions, which proved to be highly diastereoselective.
- De Graaff,Bensch,Van Lint, Matthijs J.,Ruijter,Orru
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supporting information
p. 10108 - 10112
(2015/10/20)
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- IBX oxidation of benzenedimethanols in the presence of cucurbit[8]uril
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The cucurbit[8]uril (Q[8]) mediated oxidation of benzenedimethanols with o-iodoxybenzoic acid (IBX) in aqueous solution has been investigated, and the results reveal the supramolecular catalysis depends on the electronic and geometric structure of substrate. In the cases of o-benzenedimethanol (1a) and m-benzenedimethanol (1b), the IBX oxidation could be obviously enhanced by the addition of Q[8] at different extent. There is no observation of the catalytic activity of Q[8] when p-benzenedimethanol (1c) is subjected to the IBX oxidation. The addition amount of Q[8] is discussed herein, and the addition of more than 10% mol catalyst cannot improve the oxidation much more. The investigation of host-guest interactions by isothermal titration calorimetry implies the supramolecular catalysis is related to the formation of complexes between benzenedimethanols and cucurbit[8]uril. The supramolecular catalysis of Q[8] (cucurbit[8]uril) on the IBX (o-iodoxybenzoic acid) oxidation of o,m,p-benzenedimethanols in aqueous solvent and the host-guest interactions have been investigated.
- Cong, Hang,Chen, Qiuju,Geng, Qingxia,Tao, Zhu,Yamato, Takehiko
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p. 545 - 549
(2015/05/27)
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- Unexpected dehomologation of primary alcohols to one-carbon shorter carboxylic acids using o-iodoxybenzoic acid (IBX)
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A novel and efficient transformation of primary alcohols to one-carbon shorter carboxylic acids using IBX is reported. Mechanistic studies revealed that the combination of IBX and molecular iodine produces a different active hypervalent iodine species.
- Xu, Shu,Itto, Kaori,Satoh, Masahide,Arimoto, Hirokazu
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supporting information
p. 2758 - 2761
(2014/03/21)
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- Regioselective dehydrogenation of 3-keto-steroids to form conjugated enones using o-iodoxybenzoic acid and trifluoroacetic acid catalysis
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Mild and regioselective conversion of 3-keto-5α- and 3-keto-5β-steroids (trans A/B- and cis A/B-ring juncture, respectively) to the corresponding enones (Δ1- and Δ4-3- ketones) by treatment with o-iodoxybenzoic acid (IBX) catalyzed by trifluoroacetic acid (TFA) in DMSO, is described. The IBX-mediated reaction involved dehydrogenation of the α- and β-hydrogen atoms of the 3-ketones to give the enones regioselectively in good isolated yields without concomitant formation of related dienones and trienones.
- Iida, Takashi,Omura, Kaoru,Sakiyama, Ryou,Kodomari, Mitsuo
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- Solution Phase Processes for the Manufacture of Macrocyclic Depsipeptides and New Intermediates
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The invention relates to a method or process for solution phase chemical manufacture of depsipeptides of the formula I, wherein the symbols have the meaning defined in the description, to new intermediates and their manufacture, as well as related invention embodiments.
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Page/Page column
(2014/04/18)
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- A macrolactonisation approach to the cembrane carbocycle of bielschowskysin
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By judicious choice of a conformationally constraining unit to predispose cyclisation to a 15-membered ring, we present a straightforward strategy to a cembranolide precursor of bielschowskysin by the Sonogashira coupling of two readily prepared fragments (from d-glucose and l-malic acid) followed by a facile β-acylketene macrolactonisation reaction.
- Yang, Eugene G.,Sekar, Karthik,Lear, Martin J.
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supporting information
p. 4406 - 4408
(2013/07/26)
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- Synthesis and nanostructures of 5,10,15,20-tetrakis(4-piperidyl)porphyrin
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A new water-soluble porphyrin, 5,10,15,20-tetrakis(4-piperidyl)porphyrin (T(4-Pip)P), has been synthesized. T(4-Pip)P is related to the extensively studied water-soluble porphyrin 5,10,15,20-tetrakis(4-pyridyl)porphyrin (T(4-Py)P) but has substituents with different electronic and hydrogen-bonding properties and is soluble over a much larger pH range due to the higher pK a of its conjugate acid T(4-H-Pip)P4+. Investigations of the ionic self-assembly reactions of T(4-H-Pip)P4+ with anionic water-soluble porphyrins reveal that it forms nanoscale materials.
- Jacobsen, John L.,Berget, Patrick E.,Varela, Michael C.,Vu, Tony,Schore, Neil E.,Martin, Kathleen E.,Shelnutt, John A.,Santos, Luís M.,Medforth, Craig J.
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p. 10507 - 10515
(2013/11/19)
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- 2-Iodoxybenzoic acid organosulfonates: Preparation, X-ray structure and reactivity of new, powerful hypervalent iodine(v) oxidants
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New powerful hypervalent iodine(v) oxidants, tosylate and mesylate derivatives of 2-iodoxybenzoic acid (IBX), were prepared by the reaction of IBX with the corresponding sulfonic acids. Single crystal X-ray crystallography of the diacetate derivative of IBX-tosylate revealed an unusual heptacoordinated iodine geometry without any significant intermolecular secondary interactions.
- Yusubov, Mekhman S.,Svitich, Dmitrii Yu.,Yoshimura, Akira,Nemykin, Victor N.,Zhdankin, Viktor V.
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supporting information
p. 11269 - 11271
(2013/12/04)
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- An efficient synthesis of 7α,12α-dihydroxy-4-cholesten-3-one and its biological precursor 7α-hydroxy-4-cholesten-3-one: Key intermediates in bile acid biosynthesis
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This paper describes a method for the chemical synthesis of 7α,12α-dihydroxy-4-cholesten-3-one (1a) and its biological precursor, 7α-hydroxy-4-cholesten-3-one (1b), both of which are key intermediates in the major pathway of bile acid biosynthesis from cholesterol. The principal reactions involved were (1) building of the cholesterol (iso-octane) side chain by 3-carbon elongation of the cholane (iso-pentane) one, (2) oxidation sequence to transform the 3a-hydroxy group of the steroidal A/B-ring to the desired 4- en-3-one system, and (3) appropriate protection strategy for hydroxy groups in the positions at C-7 and C-12 in the steroid nucleus. The absolute structure of 1a and 1b were confirmed by NMR and X-ray crystallography. The targeted compounds 1a and 1b, prepared in 11 steps from 2a and 2b respectively, should be useful for biochemical studies of bile acid biosynthesis or clinical studies of bile acid metabolism, as plasma levels of 1b (also termed C4) have been shown to correlate highly with the rate of bile acid biosynthesis in man.
- Ogawa, Shoujiro,Zhou, Biao,Kimoto, Yusuke,Omura, Kaoru,Kobayashi, Akiko,Higashi, Tatsuya,Mitamura, Kuniko,Ikegawa, Shigeo,Hagey, Lee R.,Hofmann, Alan F.,Iida, Takashi
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p. 927 - 937
(2013/10/21)
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- Chemo-selective oxidation of hydroxybenzyl alcohols with IBX in the presence of hemicucurbit[6]uril
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The chemo-selective oxidation of bifunctional substrates via a supramolecular strategy has been achieved. IBX (o-iodoxybenzoic acid) oxidations of hydroxybenzyl alcohols produce the corresponding aldehyde and o-quinones, while the presence of HemiQ[6] can restrain the IBX oxidation of phenolic hydroxyl groups to afford the aldehyde product. The conversion and reaction rate are greatly affected by the structures of substrates, and the stereo effect and electronic effect play very important roles in the selective oxidation system. Various spectroscopies, including 1H NMR (proton nuclear magnetic resonance), IR (infrared), and UV-vis (ultra violet-visible) have been employed to confirm the host-guest interaction of HemiQ[6] with hydroxybenzyl alcohols.
- Cong, Hang,Yamato, Takehiko,Tao, Zhu
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p. 3778 - 3783
(2013/11/06)
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- Regio-and enantioselective bioreduction of methyleneketoesters using both polymeric resin and cellulose matrix
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Methyleneketoesters were prepared in >90% yield by performing an IBX oxidation of Morita-Baylis-Hillman adducts. A methodology was developed to achieve methyl 3-aryl-3-keto-2-methylenepropanoate reduction using a screening of yeast strains in three different reaction procedures to obtain products with both high yield and diastereoselectivity. The reactions conducted in water provided inferior yields (50%) for substrates 2b-c. Employing Amberlite XAD7HP which was a substrate reservoir that also immediately extracted the products from the reaction medium after their formation, syn-4a-c and anti-4a-c were isolated in 60-70% yield, with high stereoselectivity (98-99% ee). The best results were obtained using substrates adsorbed on filter paper which provided products yields above 70%, a 99% ee and a diastereomoeric ratio (syn-4: anti-4) 9:1. Cellulose matrix has excellent potential to be successfully employed in general biocatalytic reactions.
- Chaves, Michel R.B.,Moran, Paulo J.S.,Rodrigues, J. Augusto R.
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- Oxidative homologation of aldehydes to α-ketoaldehydes by using iodoform, o-iodoxybenzoic acid, and dimethyl sulfoxide
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An efficient three-step synthetic route to α-ketoaldehydes starting from aryl aldehydes is reported. The aldehydes were treated with iPrMgCl and iodoform to obtain β-diiodoalcohols, which were then oxidized with o-iodoxybenzoic acid at room temperature to the corresponding β-diiodoketones. Subsequent reaction of the β-diiodoketone to the α-ketoaldehyde occurred under oxygen transfer from dimethyl sulfoxide. These sensitive products were in situ cyclized with o-phenylenediamine to form the stable monosubstituted quinoxalines, which could be characterized and isolated easily. α-Ketoaldehydes are a versatile, highly reactive moiety for the synthesis of heterocyclic compounds. We investigated the transformation of aldehydes into α-ketoaldehydes via β-diiodoketone intermediates and finally applied the procedure to the synthesis of peptidic substrates. Copyright
- Zall, Andrea,Bensinger, Dennis,Schmidt, Boris
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experimental part
p. 1439 - 1447
(2012/04/04)
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- Enantioselective total synthesis of pladienolide B: A potent spliceosome inhibitor
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An enantioselective and convergent total synthesis of pladienolide B (1) is described. Pladienolide B binds to the SF3b complex of a spliceosome and inhibits mRNA splicing activity. The synthesis features an epoxide opening reaction, an asymmetric reduction of a β-keto ester, and a cross metathesis strategy for the side chain synthesis.
- Ghosh, Arun K.,Anderson, David D.
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supporting information
p. 4730 - 4733
(2013/01/15)
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- Enantioselective direct aldol reactions of achiral ketones with racemic enolizable α-substituted aldehydes: Scope and limitations
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Aldol reactions of racemic enolizable dioxolan-protected α-substituted-β-ketoaldehydes with representative achiral ketones catalyzed by proline or 5-(2-pyrrolidine-2-yl)-1H-tetrazole in wet DMSO proceed with dynamic kinetic resolution (or via DYKAT with an α-substituted- β-alkoxyaldehyde) to give adducts with high dr and ee. Georg Thieme Verlag Stuttgart.
- Ward, Dale E.,Jheengut, Vishal,Beye, Garrison E.,Gillis, H. Martin,Karagiannis, Athanasios,Becerril-Jimenez, Fabiola
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supporting information; experimental part
p. 508 - 512
(2011/04/24)
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- Asymmetric de novo synthesis of fluorinated d-glucitol and d-mannitol analogues
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A highly efficient anti-SE2′ electrophilic fluorination of enantioenriched allylsilanes a subsequent dihydroxylation of the resulting allylic fluorides were used as key steps for the synthesis of three fluorinated carbohydrate analogues, 1,5-di-O-benzyl-2-deoxy-2-fluoro-d-glucitol, 2,6-di-O-benzyl-5-deoxy-5-fluoro-l-glucitol and 1,5-di-O-benzyl-2-deoxy-2-fluoro-d-mannitol. A new catalytic asymmetric route to 1-benzyloxy-4-trimethylsilyl-but-3-yn-2-ol, a common precursor to two advanced allylsilanes, is also described featuring a Noyori asymmetric transfer hydrogenation reaction.
- Giuffredi, Guy T.,Purser, Sophie,Sawicki, Marcin,Thompson, Amber L.,Gouverneur, Veronique
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experimental part
p. 910 - 920
(2009/09/25)
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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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- COMPOUNDS AND METHODS FOR TREATING INFLAMMATORY AND FIBROTIC DISORDERS
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Disclosed are compounds and methods for treating inflammatory and fibrotic disorders, including methods of modulating a stress activated protein kinase (SAPK) system with an active compound, wherein the active compound exhibits low potency for inhibition of the p38 MAPK; and wherein the contacting is conducted at a SAPK-modulating concentration that is at a low percentage inhibitory concentration for inhibition of the p38 MAPK by the compound. Also disclosed are derivatives and analogs of pirfenidone, useful for modulating a stress activated protein kinase (SAPK) system.
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Page/Page column 86
(2009/12/28)
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- Stereoselective cyclization reactions of IBX-generated alkoxyamidyl radicals
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In this paper, a method for the generation of alkoxyamidyl radicals is presented. These N-centered radicals can efficiently be formed starting from the corresponding acylated alkoxyamines using IBX as an oxidant. Stereoselective 5-exo and 6-exo reactions with these N-heteroatom-centered radicals leading to isoxazolidines and [1,2]oxazinanes are discussed. The N-O bond in the heterocycles can readily be cleaved with SmI2 to provide N-acylated 1,3-amino alcohols.
- Janza, Birgit,Studer, Armido
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p. 6991 - 6994
(2007/10/03)
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- Mild oxidation of alcohols with O-lodoxybenzoic acid (IBX) in ionic liquid 1-butyl-3-methyl-imidazolium chloride and water
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(Matrix presented) A mild, efficient, and eco-friendly procedure for the oxidation of alcohols with IBX in ionic liquid [bmim]Cl and water has been developed. Simply stirring of a solution of the alcohol and IBX in [bmim]Cl/water at room temperature followed by extraction with ether or ethyl acetate and removal of the solvent gives excellent yields of the corresponding carbonyl compounds. Recycling and reuse of the oxidant and ionic liquid have also been reported.
- Liu, Zhi,Chen, Zhen-Chu,Zheng, Qin-Guo
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p. 3321 - 3323
(2007/10/03)
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- Magnesium amide base-mediated enantioselective deprotonation processes
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A novel homochiral magnesium bisamide has been readily prepared and, following careful optimisation, this species has been shown to react efficiently with a series of prochiral 4-substituted cyclohexanones in the presence of TMSCl to give the corresponding silyl enol ethers in enantiomeric ratios of up to 95:5. Additionally, the same chiral base system has been shown to be highly effective in the desymmetrisation of cis-2,6-disubstituted cyclohexanones, providing excellent levels of both conversion and enantioselection (up to >99.5:0.5 er). Furthermore, the magnesium bisamide has also been shown to mediate a kinetic resolution process with the corresponding trans-disubstituted substrates, allowing access to enantioenriched enol ethers and ketones.
- Henderson, Kenneth W,Kerr, William J,Moir, Jennifer H
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p. 4573 - 4587
(2007/10/03)
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- Racemic and enantiopure 4-(piperidine-2′-yl)-pyridazines: Novel synthesis of anabasine-analogues with potential nicotinic acetylcholine receptor agonist activity - A new approach via Diels-Alder reaction with inverse electron demand
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A novel multistep synthesis of anabasine analogues bearing a bioisosteric pyridazine moiety instead of a pyridine nucleus in 2-position of the piperidine ring of the alkaloid is described. Starting materials are racemic 2-hydroxymethyl-piperidine, racemic pipecolic acid or (S)-(-)-piperidine-1,2-dicarboxylic-acid-1-tert-butyl ester. Key step of this synthetic approach is a Diels-Alder cycloaddition process with inverse electron demand utilizing diverse 1,2,4,5-tetrazines as electron-deficient dienes and the new racemic or enantiopure 2-(2′-methoxyethenyl)-piperidine as electron-rich dienophile. In this [4+2]-cycloadditions 1,2,4,5-tetrazines serve as synthons for introducing the pyridazine ring in the 2-position of the piperidine moiety.
- Stehl, Astrid,Seitz, Gunther,Schulz, Karen
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p. 1343 - 1354
(2007/10/03)
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- Syntheses of (diacetoxyiodo)arenes or iodylarenes from iodoarenes, with sodium periodate as the oxidant
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Easy, safe, and effective novel methods for preparing either (diacetoxyiodo)-(arenes, ArI(OAc)2, or iodylarenes, ArIO2, from the corresponding iodoarenes, ArI, using sodium periodate as the oxidant are presented in this paper. In order to obtain 2- and 4-iodylbenzoic acids, the respective sodium salts of 2- and 4-iodobenzoic acids should be used as the starting substrates, because mixtures containing the corresponding iodosyl derivatives as the main products along with the intended iodyl compounds are produced from the free parent acids.
- Kazmierczak, Pawel,Skulski, Lech,Kraszkiewicz, Lukasz
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p. 881 - 891
(2007/10/03)
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- Hypervalent Iodine Oxidations: Structure and Kinetics of the Reactive Intermediates in the Oxidation of Alcohols and 1,2-diols by o-Iodoxybenzoic Acid (IBX) and Dess-Martin Periodinane. A Comparative 1H-NMR Study
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Alcohols and 1,2-diols oxidation by o-iodoxybenzoic acid (IBX) has been examined by 1H-NMR spectroscopy.Reversible formation of reactive intermediates, iodic esters 5, has been observed, and their structures in DMSO-d6 solution have been defined as 10-I-4 axial alkoxyiodinane oxides by comparison of the chemical shift difference data with those obtained for Dess-Martin periodinane (DMP)-alcoholate and -diolate adducts.The dichotomous behaviour exhibited by IBX and DMP with 1,2-diols can be explained in terms of the different architecture of the reactive intermediates involved in the oxidation.With aliphatic alcohols, kinetic evidences support a two-step reaction mechanism involving a fast pre-equilibrium step leading to 5, followed by a rate-determining disproportionation step.With electronically activated benzyl alcohol, the attainment of pre-equilibrium is largely dependent on initial water concentration as a consequence of a particularly high K2 value.The influence of the alcohol structure on measured equilibrium (Keq) and rate constants (K2) and the effect of water on the overall reaction rate are discussed.
- Munari, Sergio De,Frigerio, Marco,Santagostino, Marco
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p. 9272 - 9279
(2007/10/03)
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- A Mild Oxidizing Reagent for Alcohols and 1,2-Diols: o-Iodoxybenzoic Acid (IBX) in DMSO
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o-Iodoxybenzoic acid (IBX) smoothly oxidizes primary and secondary alcohols to aldehydes and ketones, respectively. 1,2-Diols are converted to α-ketols or α-diketones without any oxidative cleavage of the glycol C-C bond.IBX oxidations are easily conducted in DMSO solution at room temperature, with yields ranging from good to quantitative.
- Frigerio, Marco,Santagostino, Marco
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p. 8019 - 8022
(2007/10/02)
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- A useful 12-i-5 triacetoxyperiodinane (the dess-martin periodinane) for the selective oxidation of primary or secondary alcohols and a variety of related 12-i-5 species1a
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The stable 10-I-4 species 1-hydroxy-1,3-dihydro-3,3-bis(trifluoromethyl)-1,2-benziodoxole 1-oxide ((fluoroalkoxy)iodinane oxide 7) is the ring-closed form of o-iodoxyhexafluorocumyl alcohol. It is prepared by the oxidation of chloroiodinane 6 with potassium bromate in aqueous sulfuric acid. The X-ray crystal structure of the tetrabutylammonium salt of 7 (10-I-4 anion 10) showed the unusual feature of an apical, negatively charged oxide ligand. Iodinane oxides 1 and 7 are readily converted to stable 12-1-5 periodinanes by treatment with carboxylic acid anhydrides or sulfur tetrafluoride. Tris(acyloxy)periodinanes 13 and 14 (derived from the ring-closed form of o-iodoxybenzoic acid), 1-hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide (1), and 17 and 18 (derived from 7) are extraordinarily stable. 1,1,1-Triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one (13), the "Dess-Martin Periodinane", is an extremely useful reagent for the conversion of primary and secondary alcohols to aldehydes and ketones at 25°C. It does not oxidize aldehydes to carboxylic acids under these conditions. It selectively oxidizes alcohols in the presence of furan rings or sulfides and does not react with vinyl ethers. Geraniol is oxidized to geranial by 13 without isomerization to nerol. Benzylic or allylic alcohols are selectively oxidized in the presence of saturated alkanols. The alcohol oxidation mechanism involves intermediates with alkoxy ligands replacing acetoxy ligands at the 12-I-5 iodine. It also oxidizes N-benzylbenzamide to benzaldehyde. Four other 12-I-5 species, 1,1,1-tris(trifluoroacetoxy)-1,1-dihydro-1,2-benziodoxol-3(1H)-one (14), 1,1,1,-trinuoro-1,1-dihydro-1,2-benziodoxol-3(1H)-one (15), 1,1,1-tris(acetoxy)-1,1,1,3-tetrahydro-3,3-bis(trifluoromethyl)-1,2-benziodoxole (17), and 1,1,1 -tris(trifluoroacetoxy)-1,1,1,3-tetrahydro-3,3-bis(trifluoromethyl)-1,2- benziodoxole (18), also oxidize alcohols to aldehydes and ketones. All of the tris(acyloxy)periodinanes undergo facile ligand exchange with alcohols. The reaction between triacetoxyperiodinane 13 and pinacol gives an isolable, crystalline, spirobicyclic periodinane, 25. The acetoxy group of periodinane 25 undergoes degenerate ligand exchange with acetic acid rapidly on the NMR time scale.
- Dess, Daniel B.,Martin
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p. 7277 - 7287
(2007/10/02)
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- Readily Accessible 12-I-5 Oxidant for the Conversion of Primary and Secondary Alcohols to Aldehydes and Ketones
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Periodinane 2 is a mild, selective reagent for the oxidation of primary and secondary alcohols to aldehydes and ketones.
- Dess, D. B.,Martin, J. C.
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p. 4155 - 4156
(2007/10/02)
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