- 164. The Mild Bromination of Adamantane and (Trimethylsilyl)adamantanes
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Small amounts of H2O or MeOH catalyze the reaction of Br2 with adamantane and its 1-(trimethylsilyl) and 1,3-bis(trimethylsilyl) derivatives.
- Grob, Cyril A.,Sawlewicz, Pawel
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- H-coupled electron transfer in alkane C-H activations with halogen electrophiles
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The mechanisms for the reactions of isobutane and adamantane with polyhalogen electrophiles (HHal2+, Hal3+, Hal5+, and Hal7+, Hal = Cl, Br, or I) were studied computationally at the MP2 and B3LYP levels of theory with the 6-31G** (C, H, Cl, Br) and 3-21G* (I) basis sets, as well as experimentally for adamantane halogenations in Br2, Br2/HBr, and I+Cl-/CCl4. The transition structures for the activation step display almost linear C···H···Hal interactions and are characterized by significant charge transfer to the electrophile; the hydrocarbon moieties resemble the respective radical cation structures. The regiospecificities for polar halogenations of the 3°C-H bonds of adamantane, the high experimental kinetic isotope effects (kH/kD = 3-4), the rate accelerations in the presence of Lewis and proton (HBr) acids, and the high kinetic orders for halogen (7.5 for Br2) can only be understood in terms of an H-coupled electron-transfer mechanism. The three centered-two electron (3c-2e) electrophilic mechanistic concept based on the attack of the electrophile on a C-H bond does not apply; electrophilic 3c-2e interactions dominate the C-H activations only with nonoxidizing electrophiles such as carbocations. This was shown by a comparative computational analysis of the electrophilic and H-coupled electron-transfer activation mechanisms for the isobutane reaction with an ambident electrophile, the allyl cation, at the above levels of theory.
- Fokin, Andrey A.,Shubina, Tatyana E.,Gunchenko, Pavel A.,Isaev, Sergey D.,Yurchenko, Alexander G.,Schreiner, Peter R.
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- Nuclear Spin-Spin Coupling via Nonbonded Interactions. 2. γ-Substituent Effects for Vicinal Coupling Constant Involving 13C
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The well-known γ effect on 13C chemical shielding is shown to have a counterpart in vicinal coupling constants 3JCX involving a 13C nuclear spin and a trans-oriented nuclear spin X.Experimental and theoretical results for vicinal 13C1-C2-C3-1H and 13C1-C2-C3-13C coupling constants in a number of C3-substituted aliphatic compounds in the trans arrangement and alicyclic compounds show a substantial decrease relative to the parent compound.By means of modified INDO-FTP molecular orbital procedures, which permit investigation of the importance of nonbonded interactions, it is shown that the γ-substituent effects arise in a complex way from the nonbonded interactions associated with groups bonded to the C3 or γ-carbon atom.A major factor is the positive contribution to 3JCX(180 grad) from the hydrogen atoms on the γ-carbon atom of the parent compound.Methyl groups on C3 make negative contributions; a major factor is the interaction between the hydrogen atoms of the C1 methyl and the hydrogen atoms of the methyl groups on the C3 carbon atom.It is further shown that other substituents also make negative contributions, and that hydrogen atoms on the γ substituents are not essential for the observation of a negative γ effect on vicinal constants.The γ-susbtituent effects on vicinal 13C-X coupling constants appear to be general phenomena of substantial magnitude; their recognition is important for conformational and other coupling-constant studies as they lead to results which appear to be anomalous.
- Barfield, Michael,Marshall, J. L.,Canada, E. D.
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- Electrochemical-induced radical allylation via the fragmentation of alkyl 1,4-dihydropyridines
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Aldehydes are abundant chemical motifs presented in natural products and pharmaceuticals. As a radical precursor, its application is limited. Dihydropyridines (DHPs) can act as masked aldehydes, providing alkyl radicals under the activation of Lewis acid, heat, SET oxidant and light irradiation. Herein, we report the direct activation of 4-alkyl DHPs via single electron transfer at the anode. C–C bond homolysis at the C4-position of DHP generated the corresponding alkyl radical, which was captured subsequently by 2-phenyl and 2-ethoxy carbonyl allyl bromide. The following intramolecular elimination reaction afforded 20 different radical allylation products bearing various alkyl substituents with yields up to 92%.
- Chen, Xiaoping,Luo, Xiaosheng,Wang, Ping
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- Method for synthesizing and preparing amantadine dry product
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The invention discloses a synthesis and preparation method of an amantadine dry product, and relates to the technical field of amantadine preparation. The method mainly comprises adamantane, nitrogendioxide, ozone, hydrazine hydrate, ethanol, diethyl ether, ferric chloride hexahydrate and activated carbon, and comprises the following steps: synthesis of a nitro compound: adding adamantane and dichloromethane into a flask according to a ratio of 1g: 120ml, stirring at a certain temperature, introducing 30 equivalents of nitrogen dioxide under a certain condition, introducing ozone at a low speed, reacting for 30 minutes, adding a sodium bicarbonate solution, washing the organic phase to be neutral, performing drying, and carrying out rotary evaporation to obtain the product 1-nitro adamantane. The dry amantadine product is prepared through a hydrazine hydrate reduction method, corresponding purification is conducted, the whole reaction process is mild, the process steps are simple andconvenient, the requirement for equipment is simple, the conversion rate is very high, and the method has the value of industrial batch production popularization.
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Paragraph 0057-0063; 0068
(2021/03/13)
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- Amantadine hydrochloride and preparation method thereof
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The invention discloses amantadine hydrochloride and a preparation method thereof, and relates to the technical field of amantadine hydrochloride synthesis. The method aims at solving the problems that the reaction time is too long and the yield of amantadine hydrochloride is not high. The amantadine hydrochloride is prepared from the following components, by weight: 5mmol of nitro compound, 5g ofcatalyst, 15ml of absolute ethyl alcohol, 15ml of concentrated hydrochloric acid, 15ml of hydrazine hydrate and 3ml of sodium hydroxide solution, The preparation method of amantadine hydrochloride comprises the following steps: respectively adding a nitro compound, absolute ethyl alcohol and a catalyst into a 50mL flask; in the production process of the hydrazine hydrate catalytic reduction method, no pollution is caused, the yield is high, the reaction conditions are mild, the yield of the nitro compound is 90%, the conversion rate of the nitro compound subjected to hydrazine hydrate catalytic reduction is 98.5%, the yield of the obtained amantadine hydrochloride is 89.5%, and compared with other processes, the yield is higher, the operation is simple, and the efficiency is high.
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Paragraph 0065-0072; 0081-0088
(2021/03/18)
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- Manganese/bipyridine-catalyzed non-directed C(sp3)–H bromination using NBS and TMSN3
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A Mn(II)/bipyridine-catalyzed bromination reaction of unactivated aliphatic C(sp3)?H bonds has been developed using N-bromosuccinimide (NBS) as the brominating reagent. The reaction proceeded in moderate-to-good yield, even on a gram scale. The introduced bromine atom can be converted into fluorine and allyl groups.
- Sneh, Kumar,Torigoe, Takeru,Kuninobu, Yoichiro
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supporting information
p. 885 - 890
(2021/05/05)
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- Thiourea-Mediated Halogenation of Alcohols
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The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.
- Mohite, Amar R.,Phatake, Ravindra S.,Dubey, Pooja,Agbaria, Mohamed,Shames, Alexander I.,Lemcoff, N. Gabriel,Reany, Ofer
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p. 12901 - 12911
(2020/11/26)
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- Mechanism of Ni-catalyzed oxidations of unactivated C(sp3)-H Bonds
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The Ni-catalyzed oxidation of unactivated alkanes, including the oxidation of polyethylenes, by meta-chloroperbenzoic acid (mCPBA) occur with high turnover numbers under mild conditions, but the mechanism of such transformations has been a subject of debate. Putative, high-valent nickel-oxo or nickel-oxyl intermediates have been proposed to cleave the C-H bond, but several studies on such complexes have not provided strong evidence to support such reactivity toward unactivated C(sp3)-H bonds. We report mechanistic investigations of Ni-catalyzed oxidations of unactivated C-H bonds by mCPBA. The lack of an effect of ligands, the formation of carbon-centered radicals with long lifetimes, and the decomposition of mCPBA in the presence of Ni complexes suggest that the reaction occurs through free alkyl radicals. Selectivity on model substrates and deuterium-labeling experiments imply that the m-chlorobenzoyloxy radical derived from mCPBA cleaves C-H bonds in the alkane to form an alkyl radical, which subsequently reacts with mCPBA to afford the alcohol product and regenerate the aroyloxy radical. This free-radical chain mechanism shows that Ni does not cleave the C(sp3)-H bonds as previously proposed; rather, it catalyzes the decomposition of mCPBA to form the aroyloxy radical.
- Qiu, Yehao,Hartwig, John F.
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supporting information
p. 19239 - 19248
(2020/11/13)
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- Dual nickel- and photoredox-catalyzed reductive cross-coupling of aryl vinyl halides and unactivated tertiary alkyl bromides
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A novel reductive cross-coupling of aryl vinyl halides and unactivated tertiary alkyl bromides has been realized via photoredox/nickel dual catalysis to produce vinyl arene derivatives bearing all-carbon quaternary centers with excellent E-selectivity. A stoichiometric metal reductant could be avoided by employing commercially available N,N,N′,N′-tetramethylethylenediamine (TMEDA) as the terminal reductant.
- Yu, Weijie,Chen, Long,Tao, Jiasi,Wang, Tao,Fu, Junkai
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supporting information
p. 5918 - 5921
(2019/05/27)
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- Synthesis and cytotoxicity of novel simplified eleutherobin analogues as potential antitumour agents
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Mixed simplified structures containing the paclitaxel and eleutherobin pharmacophore moieties were analyzed using molecular docking techniques and synthesized based on adamantane and 8-oxabicyclo[3.2.1]octane scaffolds. The crucial role of substituents' stereochemistry in biological activity is discussed. At micromolar concentrations the selected analogues interfered with tubulin dynamics in vitro and in a living organism. Furthermore, new compounds were cytotoxic against human tumour cell lines. The simplified eleutherobin analogues may be considered as prototypes of a new class of antitumour agents.
- Sosonyuk, Sergey E.,Peshich, Anita,Tutushkina, Anastasia V.,Khlevin, Dmitry A.,Lozinskaya, Natalia A.,Gracheva, Yulia A.,Glazunova, Valeria A.,Osolodkin, Dmitry I.,Semenova, Marina N.,Semenov, Victor V.,Palyulin, Vladimir A.,Proskurnina, Marina V.,Shtil, Alexander A.,Zefirov, Nikolay S.
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supporting information
p. 2792 - 2797
(2019/03/12)
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- Preparation method of rimantadine hydrochloride preparation
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The invention discloses a preparation method of a rimantadine hydrochloride preparation. The preparation method comprises the following steps: preparation of 1-bromoadamantane, preparation of amantadecanoic acid, preparation of adamantanecarbonyl chloride, preparation of adamantyl methy ketone, preparation of 1-amantadine methyl ketone oxime, preparation of rimantadine hydrochloride, and preparation of the rimantadine hydrochloride preparation. The preparation of adamantyl methy ketone comprises the following steps: adding (CH3)3Sb and nickelous formate into a flask; dropwise adding an acetonitrile solution of adamantanecarbonyl chloride, wherein adamantanecarbonyl chloride reacts with (CH3)3Sb to generate adamantyl methy ketone; after reaction, pouring a reaction liquid into ice water; and filtering and drying the mixture to obtain a light yellow precipitate, thereby obtaining the adamantyl methy ketone. The preparation method has the beneficial effects that the preparation method ofrimantadine hydrochloride preparation is good in environmental protection, mild in condition of a synthetic method, simple and feasible in process and high in product yield.
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Paragraph 0026; 0028; 0037; 0046
(2019/02/04)
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- Synthesizing method of rimantadine hydrochloride
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The invention discloses a synthesizing method of rimantadine hydrochloride. The synthesizing method comprises the following steps of preparing of 1-bromoadamantane, preparing of adamantane carboxylicacid, preparing of adamantanecarbonyl chloride, preparing of adamantyl methyl ketone, preparing of 1-amantadine methyl ketone oxime, preparing of rimantadine hydrochloride, and preparing of a rimantadine hydrochloride preparation; in the preparing process of adamantyl methyl ketone: adding trimethylaluminum and cerium formate into a flask, then dripping a benzene solution of adamantanecarbonyl chloride, and enabling the adamantanecarbonyl chloride and the trimethylaluminum to react and generate adamantyl methyl ketone; after reaction is finished, pouring a reaction solution into ice water, filtering and drying, so as to obtain a light yellow precipitate, namely the adamantyl methyl ketone. The synthesizing method has the beneficial effects that the conditions are mild, and the technology is simple and feasible; the usage amount of catalyst is small, the environment-friendly effect is realized, and the yield of product is high.
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Paragraph 0022; 0025; 0027; 0035; 0043
(2019/02/21)
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- A kind of anti-influenza virus preparation
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The present invention discloses an anti-influenza virus preparation, including 1 - bromo adamantane preparation, adamantane formic acid preparation, adamantane chloride preparation, adamantane methyl preparation, 1 - adamantane methyl oxime preparation, hydrochloric acid rimantadine preparation, anti-influenza virus preparation, wherein the adamantane methyl preparation steps are as follows: in the flask to join the three trimethylaluminum, formic acid cerium, then dropwise adamantane formyl chloride [...], the adamantane chloride with three methyl aluminum reaction generating adamantane methyl ketone, after the reaction is completed in the reaction liquid into ice water, then filtering, drying, the resulting pale yellow precipitate adamantane methyl ketone. The beneficial effects: preparation method of this invention mild condition, the process is simple and feasible, high product yield, the system anti- influenza virus preparation can be effective prevention and treatment of type a/b influenza virus infection, also can effectively alleviate the symptoms of the common cold.
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Paragraph 0026; 0028; 0037; 0046
(2019/03/15)
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- Preparation method of 1-adamantyl methy ketone
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The invention belongs to the field of preparation of chemical intermediates, and particularly relates to a preparation method of 1-adamantyl methy ketone. The preparation method comprises the following steps of step 1, enabling adamantane and liquid bromine to react, so as to obtain 1-bromoadamantane; step 2, using concentrated sulfuric acid as a catalyst, adding the 1-bromoadamantane and n-hexane, and dripping formic acid, so as to obtain 1-adamantanecarboxylic acid; step 3, enabling the 1-adamantanecarboxylic acid and thionyl chloride to react, heating and refluxing, extracting by benzene, and directly applying the extracting liquid for the reaction in next step; step 4, dripping a mixed solution of benzene, diethyl malonate and anhydrous ethyl alcohol into a mixed solution of magnesiumpowder, iodine, anhydrous ethyl alcohol and benzene, dripping a benzene solution of 1-adamantanecarbonyl chloride, extracting by benzene, drying and distilling, so as to obtain 2- adamantanecarbonyl diethyl malonate; step 5, adding glacial acetic acid, water and concentrated sulfuric acid into the residue. The preparation method has the advantage that the yield rate is high.
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Paragraph 0011; 0014
(2019/06/08)
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- Production method of 1-bromoadamantane
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The invention discloses a production method of 1-bromoadamantane. The production method of the 1-bromoadamantane is characterized by comprising the steps of using adamantane as an initial raw material, using 1,3-dibromo-5,5-dimethylhydantoin as a green bromination agent, and carrying out a mild bromination reaction in trichloromethane to obtain a high-purity target product. According to the production method of the 1-bromoadamantane, a synthesis technology is environmentally friendly, operation is convenient, and the raw materials are cheap and easy to obtain, so that the production method ofthe 1-bromoadamantane is suitable for large-scale industrial production.
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Paragraph 0024-0037
(2019/10/17)
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- Novel memantine analogue and synthesis method thereof
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The invention provides a novel memantine analogue and salts thereof. The structure of the memantine analogue is expressed as a formula I which is as shown in description. The invention also disclosesa synthesis method of the compound expressed as the formula I. The novel memantine analogue has better activity; the novel memantine analogue is more beneficial to clinical application and further development and research of the medicines.
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Paragraph 0020; 0029; 0033-0036
(2019/02/04)
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- Novel rimantadine analog and synthetic method thereof
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The invention provides a novel rimantadine analog. The novel rimantadine analog has a structure shown in formula (I). The rimantadine analog has high activity and is more beneficial to clinical use and further development and research of drugs.
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Paragraph 0033; 0035; 0037; 0038; 0039; 0040
(2019/04/17)
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- Sulphide as a leaving group: Highly stereoselective bromination of alkyl phenyl sulphides
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A conceptionally novel nucleophilic substitution approach to synthetically important alkyl bromides is presented. Using molecular bromine (Br2), readily available secondary benzyl and tertiary alkyl phenyl sulphides are converted into the corresponding bromides under exceptionally mild, acid- and base-free reaction conditions. This simple transformation allows the isolation of elimination sensitive benzylic β-bromo carbonyl and nitrile compounds in mostly high yields and purities. Remarkably, protic functionalities such as acids and alcohols are tolerated. Enantioenriched benzylic β-sulphido esters, readily prepared by asymmetric sulpha-Michael addition, produce the corresponding inverted bromides with high stereoselectivities, approaching complete enantiospecificity at -40 °C. Significantly, the reported benzylic β-bromo esters can be stored without racemisation for prolonged periods at -20 °C. Their synthetic potential was demonstrated by the one-pot preparation of γ-azido alcohol (S)-5 in 90% ee. NMR studies revealed an initial formation of a sulphide bromine adduct, which in turn is in equilibrium with a postulated dibromosulphurane intermediate that undergoes C-Br bond formation.
- Canestrari, Daniele,Cioffi, Caterina,Biancofiore, Ilaria,Lancianesi, Stefano,Ghisu, Lorenza,Ruether, Manuel,O'Brien, John,Adamo, Mauro F.A.,Ibrahim, Hasim
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p. 9042 - 9050
(2019/10/22)
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- Catalytic Bromination of Alkyl sp3C-H Bonds with KBr/Air under Visible Light
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Alkyl sp3C-H bonds of cycloalkanes and functional branch/linear alkanes have been successfully brominated with KBr using air or O2 as an oxidant at room temperature to 40 °C. The reactions are carried out in the presence of catalytic NaNO2 in 37% HCl (aq)/solvent under visible light, combining aerobic oxidations and photochemical radical processes. For various alkane substrates, CF3CH2OH, CHCl3, or CH2Cl2 is employed as an organic solvent, respectively, to enhance the efficiency of bromination.
- Zhao, Mengdi,Lu, Wenjun
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supporting information
p. 5264 - 5267
(2018/09/12)
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- KOtBu as a single electron donor? Revisiting the halogenation of alkanes with CBr4 and CCl4
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The search for reactions where KOtBu and other tert-alkoxides might behave as single electron donors led us to explore their reactions with tetrahalomethanes, CX4, in the presence of adamantane. We recently reported the halogenation of adamantane under these conditions. These reactions appeared to mirror the analogous known reaction of NaOH with CBr4 under phase-transfer conditions, where initiation features single electron transfer from a hydroxide ion to CBr4. We now report evidence from experimental and computational studies that KOtBu and other alkoxide reagents do not go through an analogous electron transfer. Rather, the alkoxides form hypohalites upon reacting with CBr4 or CCl4, and homolytic decomposition of appropriate hypohalites initiates the halogenation of adamantane.
- Emery, Katie J.,Young, Allan,Arokianathar, J. Norman,Tuttle, Tell,Murphy, John A.
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supporting information
(2018/05/22)
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- Highly selective halogenation of unactivated C(sp3)-H with NaX under co-catalysis of visible light and Ag@AgX
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The direct selective halogenation of unactivated C(sp3)-H bonds into C-halogen bonds was achieved using a nano Ag/AgCl catalyst at RT under visible light or LED irradiation in the presence of an aqueous solution of NaX/HX as a halide source, in air. The halogenation of hydrocarbons provided mono-halide substituted products with 95% selectivity and yields higher than 90%, with the chlorination of toluene being 81%, far higher than the 40% conversion using dichlorine. Mechanistic studies demonstrated that the reaction is a free radical process using blue light (450-500 nm), with visible light being the most effective light source. Irradiation is proposed to cause AgCl bonding electrons to become excited and electron transfer from chloride ions induces chlorine radical formation which drives the substitution reaction. The reaction provides a potentially valuable method for the direct chlorination of saturated hydrocarbons.
- Liu, Shouxin,Zhang, Qi,Tian, Xia,Fan, Shiming,Huang, Jing,Whiting, Andrew
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p. 4729 - 4737
(2018/10/23)
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- Preparation method of alkane brominated material
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The invention relates to a preparation method of an alkane brominated material. The preparation method comprises the following steps: adding alkane, a bromine-containing compound or elemental bromine,a catalyst and acid into a solvent; adding the solvent into a light-transmission reaction container under air or oxygen atmosphere; sealing; performing stirring reaction under constant pressure and light illumination conditions; then analyzing a nuclear magnetic yield, and performing extraction, drying, filtration, distillation under reduced pressure and column separation to obtain the alkane brominated material. Compared with the prior art, the preparation method disclosed by the invention has the advantages that by using low-cost and safe bromic salt as a bromine source, the air as an oxidizing agent and a nitrogen-containing reagent as the catalyst, reaction is carried out under the conditions of constant temperature and constant pressure, so that energy conservation and economy are realized, and the preparation method is convenient and safe to operate and is environmentally friendly.
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Paragraph 0049-0050
(2018/09/08)
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- Preparation and properties of a novel solution of hydrogen bromide (HBr) in 1,4-dioxane: An alternative reagent to HBr gas without protic solvents
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A solution of hydrogen bromide (HBr) in 1,4-dioxane was prepared and investigated for its ability to brominate alcohols, and hydrobrominate alkenes. This study revealed that the brominating ability of this HBr/1,4-dioxane solution is equal or superior to that of hydrobromic acid or HBr in acetic acid. The solution of HBr in 1,4-dioxane is robust, exhibiting no decomposition of the solvent, and retaining 97% of its original concentration, when kept at ?25 °C for 30 days. This solution is a liquid alternative to HBr gas without protic solvents.
- Nishio, Yuya,Mifune, Ryota,Sato, Taisuke,Ishikawa, Shin-ich,Matsubara, Hiroshi
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p. 1190 - 1193
(2017/03/02)
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- PROCESS FOR THE PREPARATION OF ORGANIC BROMIDES
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The present invention provides a process for the preparation of organic bromides, by a radical bromodecarboxylation of carboxylic acids with a bromoisocyanurate.
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Paragraph 00169; 00171; 00201
(2017/07/28)
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- Silver-Catalyzed Decarboxylative Bromination of Aliphatic Carboxylic Acids
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The silver-catalyzed Hunsdiecker bromination of aliphatic carboxylic acids is described. With Ag(Phen)2OTf as the catalyst and dibromoisocyanuric acid as the brominating agent, various aliphatic carboxylic acids underwent decarboxylative bromination to provide the corresponding alkyl bromides under mild conditions. This method not only is efficient and general but also enjoys wide functional group compatibility. An oxidative radical mechanism involving Ag(II) intermediates is proposed.
- Tan, Xinqiang,Song, Tao,Wang, Zhentao,Chen, He,Cui, Lei,Li, Chaozhong
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supporting information
p. 1634 - 1637
(2017/04/11)
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- Novel sulfonate-containing halogen-free flame-retardants: Effect of ternary and quaternary sulfonates centered on adamantane on the properties of polycarbonate composites
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In order to find a more environmentally friendly flame retardant, we have designed a novel halogen-free flame-retardant (FR) system consisting of ternary and quaternary sulfonates centered on adamantane. They are named 1,3,5-tri(phenyl-4-sodium sulfonate)adamantane (AS3) and 1,3,5,7-tetrakis(phenyl-4-sodium sulfonate)adamantane (AS4), respectively. Both kinds of FRs were synthesized and compounded with polycarbonate (PC) to study their effects on the properties of PC composites. The results show that the new FR system can improve PC flame retardancy efficiently, and has mechanical strength advantages as well. The PC composites with only 0.1 wt% AS3 or 0.08 wt% AS4 can pass vertical burning tests (UL-94) V-0 level, with increasing the value of limiting oxygen index (LOI) to 31.2% or 32.3%. Moreover, they can maintain ideal mechanical properties compared to neat PC simultaneously. Finally, the flame retardant mechanism of this system was verified via thermal analysis, morphology and chemical structure analysis of the char residues.
- Zhu, Dong Yu,Guo, Jian Wei,Xian, Jia Xing,Fu, Shu Qin
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p. 39270 - 39278
(2017/08/21)
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- Preparation of manganese/Graphite oxide composite using permanganate and graphite: Application as catalyst in bromination of hydrocarbons
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A highly efficient one-pot preparation of manganese/graphite oxide (MnOX/GO) composite from graphite and KMnO4 is described. Hummers preparation method of GO requires a stoichiometric amount of KMnO4, as a result, the method produces a large amount of reduced Mn species. The Mn residue generally is a waste, therefore, we envisioned converting it to value-Added materials. A MnOX/GO composite was prepared in one-pot by treating the unpurified GO with aqueous KOH. The composite was characterized by XRD, XAFS, SEM and TEM. Among various applications of the MnOX/GO composite, we applied it as a recyclable catalyst for bromination of saturated hydrocarbons, one of the most basic but important chemical transformations. The MnOX/GO composite is expected to be an efficient catalyst because of the high surface area and high accessibility of substrates derived from the 2- dimensional sheet structure. When the reaction of a saturated hydrocarbon and Br2 in the presence of catalytic MnOX/GO was performed under fluorescent light irradiation, a brominated product was formed in high yield in a short reaction time. GO could strongly bind with Mn to prevent elution to the liquid phase, enabling the high recyclability.
- Suzuki, Hideyuki,Nishina, Yuta
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- A 1 - adamantane preparation method (by machine translation)
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The invention discloses a 1 - adamantane preparation method, which belongs to the technical field of chemical industry. Comprising the following steps: (1) adamantane is added to the bromine and water in the mixed systems of, sequentially through the three temperature stages insulation reaction, reaction to produce 1 - bromoadamantane, containing the 1 - bromoadamantane mixing system; (2) the step (1) the prepared containing 1 - bromoadamantane mixed system, atmospheric distillation excess of bromine, the temperature control of the mixed system, an aqueous solution of sodium sulfite adds by drops burnt, thermal insulation reaction, to prepare the 1 - adamantane mellow thick; (3) the step (2) the prepared 1 - adamantane mellow thick added to the water and the water miscible organic solvent in the mixed solvent, adding activated carbon, heating, filtering, the filtrate crystallization, filtering, to obtain the 1 - adamantane. Preparation method of this invention, the operation is simple, and less safety risk, three wastes, high yield, is suitable for industrial production. (by machine translation)
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Paragraph 0049; 0051; 0054; 0056; 0059; 0061
(2017/08/29)
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- An efficient and selective method for the iodination and bromination of alcohols under mild conditions
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A straightforward and effective procedure for the conversion of a variety of alcohols into the corresponding alkyl iodides and bromides is described using KX/P2O5 (X = I, Br). The reactions were easily carried out in acetonitrile under mild conditions. Using this method, the selective conversion of benzylic alcohols in the presence of aliphatic alcohols was achieved.
- Khazdooz, Leila,Zarei, Amin,Aghaei, Hamidreza,Azizi, Ghobad,Gheisari, Mohammad Mehdi
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p. 168 - 171
(2015/12/30)
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- Hydroxylation versus Halogenation of Aliphatic C?H Bonds by a Dioxygen-Derived Iron–Oxygen Oxidant: Functional Mimicking of Iron Halogenases
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An iron–oxygen intermediate species generated in situ in the reductive activation of dioxygen by an iron(II)–benzilate complex of a monoanionic facial N3ligand, promoted the halogenation of aliphatic C?H bonds in the presence of a protic acid and a halide anion. An electrophilic iron(IV)–oxo oxidant with a coordinated halide is proposed as the active oxidant. The halogenation reaction with dioxygen and the iron complex mimics the activity of non-heme iron halogenases.
- Chatterjee, Sayanti,Paine, Tapan Kanti
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supporting information
p. 7717 - 7722
(2016/07/07)
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- Catalytic Access to Alkyl Bromides, Chlorides and Iodides via Visible Light-Promoted Decarboxylative Halogenation
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Herein is reported the catalytic, visible light-promoted, decarboxylative halogenation (bromination, chlorination, and iodination) of aliphatic carboxylic acids. This operationally-simple reaction tolerates a range of functional groups, proceeds at room temperature, and is redox neutral. By employing an iridium photocatalyst in concert with a halogen atom source, the use of stoichiometric metals such as silver, mercury, thallium, and lead can be circumvented. This reaction grants access to valuable synthetic building blocks from the large pool of cheap, readily available carboxylic acids.
- Candish, Lisa,Standley, Eric A.,Gómez-Suárez, Adrián,Mukherjee, Satobhisha,Glorius, Frank
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supporting information
p. 9971 - 9974
(2016/07/19)
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- A method for synthesizing diamond ethylamine
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The invention discloses a synthetic method for rimantadine. The synthetic method is characterized by comprising the following steps: firstly, obtaining 1-bromoadamantane by reacting adamantine with liquid bromine; then, acidifying to obtain adamantanecarboxylic acid after reacting 1-bromoadamantane with magnesium and anhydrous ether; obtaining adamantine carbonyl chloride by performing reflux reaction on tehadamantanecarboxylic acid with thionyl chloride; obtaining adamantane methyl ketone by reacting the adamantine carbonyl chloride with (CH3)2CdCu; and finally, obtaining the rimantadine by hydriding and reacting adamantane methyl ketone with hydrochloric acid and ammonia water in the presence of sodium borohydride. The synthetic method disclosed by the invention is gentle in condition, simple in follow-up processing, high in yield, cheap in raw material and low in synthesis cost.
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Paragraph 0041; 0042
(2017/03/22)
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- KOtBu: A Privileged Reagent for Electron Transfer Reactions?
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Many recent studies have used KOtBu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive. These reaction classes include coupling reactions of halobenzenes and arenes, reductive cleavages of dithianes, and SRN1 reactions. Direct electron transfer would imply that alkali metal alkoxides are willing partners in these electron transfer reactions, but the literature reports provide little or no experimental evidence for this. This paper examines each of these classes of reaction in turn, and contests the roles proposed for KOtBu; instead, it provides new mechanistic information that in each case supports the in situ formation of organic electron donors. We go on to show that direct electron transfer from KOtBu can however occur in appropriate cases, where the electron acceptor has a reduction potential near the oxidation potential of KOtBu, and the example that we use is CBr4. In this case, computational results support electrochemical data in backing a direct electron transfer reaction.
- Barham, Joshua P.,Coulthard, Graeme,Emery, Katie J.,Doni, Eswararao,Cumine, Florimond,Nocera, Giuseppe,John, Matthew P.,Berlouis, Leonard E. A.,McGuire, Thomas,Tuttle, Tell,Murphy, John A.
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supporting information
p. 7402 - 7410
(2016/07/06)
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- Process for preparation of amantadine free amine amantadine by use of amantadine hydrochloride
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The present invention discloses a process for preparation of amantadine free amine amantadine by use of amantadine hydrochloride, and the process is characterized as follows: in a reaction vessel, water and the amantadine hydrochloride are added in order, the mass ratio of water to amantadine hydrochloride is 1:4, and after even stirring, the pH value is adjusted to 10 with sodium hydroxide or sodium carbonate; and after solid precipitation, the stirring is continued for 0.5h, and a pure free amine amantadine product can be obtained by filtering, washing with water, and drying.
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Paragraph 0005
(2017/02/09)
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- Bromination of adamantane and its derivatives with tetrabromomethane catalyzed by iron compounds
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Catalytic bromination of adamantane and its derivatives with tetrabromomethane catalyzed by iron compounds has been performed. The favorable ratio of catalyst and reagents and the conditions of a selective synthesis of bromine-substituted adamantanes have been developed.
- Khusnutdinov,Shchadneva,Khisamova
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p. 184 - 187
(2015/04/14)
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- Halogen Exchange Reaction of Aliphatic Fluorine Compounds with Organic Halides as Halogen Source
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The halogen exchange reaction of aliphatic fluorine compounds with organic halides as the halogen source was achieved. Treatment of alkyl fluorides (primary, secondary, or tertiary fluorides) with a catalytic amount of titanocene dihalides, trialkyl aluminum, and polyhalomethanes (chloro or bromo methanes) as the halogen source gave the corresponding alkyl halides in excellent yields under mild conditions. In the case of a fluorine/iodine exchange, no titanocene catalyst is needed. Only C-F bonds are selectively activated under these conditions, whereas alkyl chlorides, bromides, and iodides are tolerant to these reactions.
- Mizukami, Yuki,Song, Zhiyi,Takahashi, Tamotsu
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supporting information
p. 5942 - 5945
(2016/01/09)
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- Site-selective aliphatic C-H bromination using N -bromoamides and visible light
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Transformations that selectively functionalize aliphatic C-H bonds hold significant promise to streamline complex molecule synthesis. Despite the potential for site-selective C-H functionalization, few intermolecular processes of preparative value exist. Herein, we report an approach to unactivated, aliphatic C-H bromination using readily available N-bromoamide reagents and visible light. These halogenations proceed in useful chemical yields, with substrate as the limiting reagent. The site selectivities of these radical-mediated C-H functionalizations are comparable (or superior) to the most selective intermolecular C-H functionalizations known. With the broad utility of alkyl bromides as synthetic intermediates, this convenient approach will find general use in chemical synthesis.
- Schmidt, Valerie A.,Quinn, Ryan K.,Brusoe, Andrew T.,Alexanian, Erik J.
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supporting information
p. 14389 - 14392
(2014/12/10)
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- Direct bromination of hydrocarbons catalyzed by Li2MnO 3 under oxygen and photo-irradiation conditions
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A method for the direct bromination of hydrocarbons with Br2 using a ubiquitous and inexpensive catalyst is highly desirable. Herein, we report the selective mono-bromination of hydrocarbons in good yield using Li2MnO3 as a catalyst under irradiation with a fluorescent room light. This new catalyst can be recycled. The effect of light was investigated using action spectra, which revealed that the reaction occurred on the surface of the catalyst.
- Nishina, Yuta,Morita, Junya,Ohtani, Bunsho
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p. 2158 - 2162
(2013/03/13)
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- Evaluation of cyclopentyl methyl ether (CPME) as a solvent for radical reactions
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We have explored the potential of cyclopentyl methyl ether (CPME) as a solvent for radical reactions. Hydrostannation, hydrosilylation, hydrothiolation, and tributyltin hydride mediated reductions were successfully carried out in CPME. GC-MS analysis indicated that CPME degraded into methyl pentanoate, cyclopentanone, 2-cyclopenten-1-ol, and cyclopentanol under thermal radical conditions, albeit only slightly. We also achieved radical-containing one-pot reactions in CPME as a demonstration of its applicability to multi-step reactions.
- Kobayashi, Shoji,Kuroda, Hiroyuki,Ohtsuka, Yuta,Kashihara, Takashi,Masuyama, Araki,Watanabe, Kiyoshi
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p. 2251 - 2259
(2013/03/29)
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- Synthesis and ring-opening reaction of novel 1,3-dehydroadamantanes possessing phenyl and alkoxyl substituents
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A series of novel 1,3-dehydroadamantanes (DHAs) possessing phenyl or alkoxyl substituents, such as 5-phenyl-1,3-dehydroadamantane, 5-butyl-7-phenyl-1,3-dehydroadamantane, 5-methoxy-1,3-dehydroadamantane, 5-butoxy-1,3-dehydroadamantane, 5-butyl-7-methoxy-1,3-dehydroadamantane, and 5-butoxy-7-butyl-1,3-dehydroadamantane were synthesized and subjected to react with acidic compounds. 1,3-Dibromoadamantanes carrying phenyl or alkoxyl substituents were converted into the corresponding DHAs via the intramolecular Wurtz-type coupling reactions with lithium metal in THF in 23-62% yields. Ring-opening reactions of DHAs readily occurred with acetic acid or methanol under acidic conditions to form various 1-acetoxyadamantanes or 1-methoxyadamantanes containing phenyl or alkoxyl groups. The resulting 1-butyl-3-methoxy-5-phenyladamantane, 1-acetoxy-3-butyl-5-phenyladamantane, 1-acetoxy-3-butyl-5-methoxyadamantane, 1-acetoxy-3-butoxy-5-butyladamantane, and 1-butoxy-3-butyl-5-methoxyadamantane possessed stereogenic center. The high reactivity of the inverted 1,3-carbon-carbon σ-bond in DHAs toward the acidic compounds indicated the high electron density, which was supported by the sp2 character of cyclopropane rings in DHAs estimated by J C-H coupling constants in the 13C NMR analyzes.
- Inomata, Sotaro,Harada, Yusuke,Matsuoka, Shin-Ichi,Ishizone, Takashi
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p. 3238 - 3248
(2013/04/24)
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- Brominated methanes as photoresponsive molecular storage of elemental Br2
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The photochemical generation of elemental Br2 from brominated methanes is reported. Br2 was generated by the vaporization of carbon oxides and HBr through oxidative photodecomposition of brominated methanes under a 20 W low-pressure mercury lamp, wherein the amount and situations of Br2 generation were photochemically controllable. Liquid CH 2Br2 can be used not only as an organic solvent but also for the photoresponsive molecular storage of Br2, which is of great technical benefit in a variety of organic syntheses and in materials science. By taking advantage of the in situ generation of Br2 from the organic solvent itself, many organobromine compounds were synthesized in high practical yields with or without the addition of a catalyst. Herein, Br2 that was generated by the photodecomposition of CH2Br2 retained its reactivity in solution to undergo essentially the same reactions as those that were carried out with solutions of Br2 dissolved in CH 2Br2 that were prepared without photoirradiation. Furthermore, HBr, which was generated during the course of the photodecomposition of CH2Br2, was also available for the substitution of the OH group for the Br group and for the preparation of the HBr salts of amines. Furthermore, the photochemical generation of Br2 from CH2Br2 was available for the area-selective photochemical bleaching of natural colored plants, such as red rose petals, wherein Br2 that was generated photochemically from CH 2Br2 was painted onto the petal to cause radical oxidations of the chromophoric anthocyanin molecules. The generation of Br 2 from brominated methanes occurred upon photoirradiation under O2. The solutions that contained elemental Br2 were useful for the synthesis of organobromine compounds and the macroscopic photochemical bleaching of colored plants. Copyright
- Kawakami, Kazumitsu,Tsuda, Akihiko
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p. 2240 - 2252
(2012/11/06)
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- In situ phosphine oxide reduction: A catalytic appel reaction
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Several important reactions in organic chemistry thrive on stoichiometric formation of phosphine oxides from phosphines. To avoid the resulting burden of waste and purification, cyclic phosphine oxides were evaluated for new catalytic reactions based on in situ regeneration. First, the ease of silane-mediated reduction of a range of cyclic phosphine oxides was explored. In addition, the compatibility of silanes with electrophilic halogen donors was determined for application in a catalytic Appel reaction based on in situ reduction of dibenzophosphole oxide. Under optimized conditions, alcohols were effectively converted to bromides or chlorides, thereby showing the relevance of new catalyst development and paving the way for broader application of organophosphorus catalysis by in situ reduction protocols. Copyright
- Van Kalkeren, Henri A.,Leenders, Stefan H. A. M.,Hommersom, C. Rianne A.,Rutjes, Floris P. J. T.,Van Delft, Floris L.
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supporting information; experimental part
p. 11290 - 11295
(2011/10/19)
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- Efficient organic transformations mediated by ZrOCl28H 2O in Water
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Operationally simple and environmentally benign methods for some organic transformations comprising reductive coupling of sulfonyl chlorides, chemoselective deoxygenation of sulfoxides, and halogenation of alcohols mediated by ZrOCl28H2O/MX in water have been developed.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Heidari, Mahdieh
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experimental part
p. 1470 - 1482
(2011/10/05)
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- Selective hydroxylation of adamantane and its derivatives
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A general method was developed for hydroxylation into the nodal position of adamantane and its 1- and 2-substituted derivatives employing systems H 2O-CBr4 (BrCCl3, CCl4) in the presence of complexes of Pd, Ni, Ru, Co, Mo, W, and Fe. The oxidants in the systems are hypochlorous (HOCl) or hypobromous (HOBr) acids generated from water and halomethanes under the reaction conditions.
- Khusnutdinov,Shchadneva,Mukhametshina,Dzhemilev
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scheme or table
p. 1137 - 1142
(2009/12/03)
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- Hexabromoacetone and ethyl tribromoacetate: a highly efficient reagent for bromination of alcohol
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A new and efficient method for the bromination of alcohols utilizing Br3CCOCBr3/PPh3 and Br3CCO2Et/PPh3 is described. Various alcohols can be converted smoothly into their corresponding alkyl bromides in high yields under mild conditions with short reaction times. Based upon 1H NMR studies using competitive reactions between selected brominating agents and Cl3CCN, Br3CCOCBr3 displays the highest reactivity approximately nine times that of CBr4.
- Tongkate, Pratoomrat,Pluempanupat, Wanchai,Chavasiri, Warinthorn
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p. 1146 - 1148
(2008/09/18)
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- 4-Aminophenyldiphenylphosphinite (APDPP), a new heterogeneous and acid scavenger phosphinite - Conversion of alcohols, trimethylsilyl, and tetrahydropyranyl ethers to alkyl halides with halogens or N-halosuccinimides
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A new heterogeneous phosphinite, 4-aminophenyldiphenylphosphinite (APDPP), is prepared and used for the efficient conversion of alcohols, trimethylsilyl ethers, and tetrahydropyranyl ethers to their corresponding bromides, iodides, and chlorides in the presence of molecular halogens or N-halosuccinimides. The amino group in this phosphinite acts as an acid scavenger and removes the produced acid. A simple filtration easily removes the phosphinate by-product.
- Iranpoor, Nasser,Firouzabadi, Habib,Gholinejad, Mohammad
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p. 1006 - 1012
(2007/10/03)
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- Facile conversion of alcohols into their bromides and iodides by N-bromo and N-iodosaccharins/triphenylphosphine under neutral conditions
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N-Bromo and N-iodosaccharins in the presence of triphenylphosphine convert alcohols into the corresponding bromides and iodides in good to excellent yields at room temperature under neutral conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Ebrahimzadeh, Farzaneh
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p. 1771 - 1775
(2007/10/03)
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- Silicaphosphine (Silphos): A filterable reagent for the conversion of alcohols and thiols to alkyl bromides and iodides
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Silicaphosphine (Silphos), [P(Cl)3-n(SiO2) n], as a new heterogeneous reagent is introduced. This reagent converts alcohols and thiols to their corresponding bromides and iodides in the presence of X2 (X=Br, I) in refluxing CH3CN in high to quantitative yields. Use of Silphos provides a highly practical method for the easy separation of the Silphos oxide byproduct by a simple filtration.
- Iranpoor, Nasser,Firouzabadi, Habib,Jamalian, Arezu,Kazemi, Foad
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p. 5699 - 5704
(2007/10/03)
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- METHOD FOR PRODUCING HALOGENATED ADAMANTANES
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PROBLEM TO BE SOLVED: To provide a method for producing a high-purity halogenated adamantanes having a small content of an impurity having halogens at the different positions and in the different proportions from those of the objective material. SOLUTION: The method for producing the halogenated adamantanes comprises using adamantanols having at least one hydroxy group bonded to an adamantane ring as a raw material, and mixing and reacting the adamantanols with a halosulfonic acid. The hydroxy groups possessed by the adamantanols are substituted with halogen atoms to provide the corresponding halogenated adamantanes. The control of the halogenated positions and the number thereof is very easy because the hydroxy groups are preferentially substituted with the halogen atoms by the method compared to the case in which the adamantane having no hydroxy group is used as the raw material and the hydrogen atom is substituted so as to be halogenated. As a result, the high-purity halogenated adamantanes having the low content of the impurities, especially the halogenated adamantanes except the objective material are obtained by using the high-purity adamantanols as the raw material in the method.
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Page/Page column 6
(2008/06/13)
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