- Concerning the preparation of 6-bromotryptamine
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Most of the previous syntheses of the marine natural product 6-bromotryptamine have almost certainly led to partial debromination resulting in an impure product containing tryptamine. We show that loss of bromine occurs when lithium aluminum hydride is employed as a reducing agent in the final reaction step leading to 6-bromotryptamine. Reductive-debromination is also likely to intrude during some of the syntheses of 6-bromoindole, the typical precursor to 6-bromotryptamine. None of the seven described syntheses of 6-bromotryptamine that involve a reduction sequence from 6-bromoindole have reported elemental analyses as a measure of purity.
- Scott Wiens,Johnson, Jerry L.,Gribble, Gordon W.
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- Nitration of deactivated aromatic compounds via mechanochemical reaction
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A variety of deactivated arenes were nitrated to their corresponding nitro derivatives in excellent yields under high-speed ball milling condition using Fe(NO3)3·9H2O/P2O5 as nitrating reagent. A radical involved mechanism was proposed for this facial, eco-friendly, safe, and effective nitration reaction.
- Wu, Jian-Wei,Zhang, Pu,Guo, Zhi-Xin
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supporting information
(2021/05/05)
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- The polyhedral nature of selenium-catalysed reactions: Se(iv) species instead of Se(vi) species make the difference in the on water selenium-mediated oxidation of arylamines
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Selenium-catalysed oxidations are highly sought after in organic synthesis and biology. Herein, we report our studies on the on water selenium mediated oxidation of anilines. In the presence of diphenyl diselenide or benzeneseleninic acid, anilines react with hydrogen peroxide, providing direct and selective access to nitroarenes. On the other hand, the use of selenium dioxide or sodium selenite leads to azoxyarenes. Careful mechanistic analysis and 77Se NMR studies revealed that only Se(iv) species, such as benzeneperoxyseleninic acid, are the active oxidants involved in the catalytic cycle operating in water and leading to nitroarenes. While other selenium-catalysed oxidations occurring in organic solvents have been recently demonstrated to proceed through Se(vi) key intermediates, the on water oxidation of anilines to nitroarenes does not. These findings shed new light on the multifaceted nature of organoselenium-catalysed transformations and open new directions to exploit selenium-based catalysis.
- Capperucci, Antonella,Dalia, Camilla,Tanini, Damiano
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supporting information
p. 5680 - 5686
(2021/08/16)
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- Pd-Catalyzed Decarboxylative Ortho-Halogenation of Aryl Carboxylic Acids with Sodium Halide NaX Using Carboxyl as a Traceless Directing Group
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A highly regioselective Pd-catalyzed carboxyl directed decarboxylative ortho-C-H halogenation of cheap o-nitrobenzoic acids with NaX (X = I, Br) under aerobic conditions has been established. The utility of the method has been demonstrated by the gram-scale reaction and derivatization of the product. Experimental results have confirmed Pd and Bi played critical roles in the transformation and indicated the transformation might proceed via 2-halo-6-nitrobenzoic acid derivative intermediate.
- Fu, Zhengjiang,Jiang, Yongqing,Wang, Shuiliang,Song, Yuanyuan,Guo, Shengmei,Cai, Hu
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supporting information
p. 3003 - 3007
(2019/05/10)
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- Preparation method of substituted nitrobenzene compound
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The invention discloses a preparation method of a substituted nitrobenzene compound. The method comprises the following steps: carrying out a decarboxylation reaction as shown below on a compound II under the action of alkali in a solvent at the temperature of 150 to 250 DEG C to obtain a compound I; the alkali is one or more of carbonates and bicarbonates of alkali metals. Compared with some metal-catalyzed decarboxylation methods, the preparation method of the substituted nitrobenzene compound has the advantages of simple operation, low production cost, convenient post-treatment and high yield, and more application values in industrial production.
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Paragraph 0088-0091
(2019/03/29)
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- A general electrochemical strategy for the Sandmeyer reaction
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Herein we report a general electrochemical strategy for the Sandmeyer reaction. Using electricity as the driving force, this protocol employs a simple and inexpensive halogen source, such as NBS, CBrCl3, CH2I2, CCl4, LiCl and NaBr for the halogenation of aryl diazonium salts. In addition, we found that these electrochemical reactions could be performed using anilines as the starting material in a one-pot fashion. Furthermore, the practicality of this process was demonstrated in the multigram scale synthesis of aryl halides using highly inexpensive graphite as the electrode. A series of detailed mechanism studies have been performed, including radical clock and radical scavenger study, cyclic voltammetry analysis and in situ electron paramagnetic resonance (EPR) analysis.
- Liu, Qianyi,Sun, Beiqi,Liu, Zheng,Kao, Yi,Dong, Bo-Wei,Jiang, Shang-Da,Li, Feng,Liu, Guoquan,Yang, Yang,Mo, Fanyang
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p. 8731 - 8737
(2018/12/10)
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- A one-pot-three-step route to triazolotriazepinoindazolones from oxazolino-2H-indazoles
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A one-pot-three-step method has been developed for the conversion of oxazolino-2H-indazoles into triazolotriazepinoindazolones with three points of diversity. Step one of this process involves a propargyl bromide-initiated ring opening of the oxazolino-2H-indazole (available by the Davis-Beirut reaction) to give an N1-(propargyl)-N2-(2-bromoethyl)-disubstituted indazolone, which then undergoes -CH2Br → -CH2N 3 displacement (step two) followed by an uncatalyzed intramolecular azide-alkyne 1,3-dipolar cycloaddition (step three) to form the target heterocycle. Employing 7-bromooxazolino-2H-indazole allows for further diversification through, for example, palladium-catalyzed coupling chemistry, as reported here.
- Conrad, Wayne E.,Rodriguez, Kevin X.,Nguyen, Huy H.,Fettinger, James C.,Haddadin, Makhluf J.,Kurth, Mark J.
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supporting information; experimental part
p. 3870 - 3873
(2012/10/07)
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- Halodeboronation of organotrifluoroborates using tetrabutylammonium tribromide or cesium triiodide
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Halodeboronation of organotrifluoroborates using commercially available tetrabutylammonium tribromide (TBATB) or cesium triiodide in aqueous medium is reported. The mild, transition metal-free method has proven to be tolerant of a wide range of functional groups. High regio- and chemoselectivity are observed. Two synthetic routes to (Z)-dibromoalkenes from alkynes, through stereodefined (Z)-2-bromoalkenyltrifluoroborates and (Z)-1,2-bis(boryl) alkenyltrifluoroborates, have been developed using the TBATB mediated bromodeboronation as the key step.
- Yao, Min-Liang,Kabalka, George W.,Blevins, David W.,Reddy, Marepally Srinivasa,Yong, Li
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experimental part
p. 3738 - 3743
(2012/06/30)
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- Chemoselective bromodeboronation of organotrifluoroborates using tetrabutylammonium tribromide: Application in (Z)-dibromoalkene syntheses
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(Chemical Equation Presented) Tetrabutylammonlum trlbromlde (TBATB) has been found to be a unique bromodeboronatlon reagent for organotrlf luoroborates. When compared to previously reported bromodeboronatlon methods, the mild and metal-free reaction conditions tolerate a wider range of functional groups. High reglo- and chemoselectlvlty are observed In the presence of both unsaturated carbon-carbon bonds and aldehyde functional groups. An efficient synthetic route to (Z)-dlbromoalkenes from terminal alkynes has been developed using the TBATB-medlated bromodeboronatlon as a key step.
- Yao, Min-Liang,Reddy, Marepally Srinivasa,Li, Yong,Walfish, Ingrid,Blevins, David W.,Kabalka, George W.
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supporting information; experimental part
p. 700 - 703
(2010/04/02)
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- Syntheses of 4-methoxymethylbenzyl permethrinates containing fluorine and their insecticidal activity
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In order to investigate the relationship between the position of fluorine atom and insecticidal activity about 4-methoxymethylbenzyl permethrinates containing fluorine, 2 and 3-fluoro-4-methoxymethylbenzyl (±)-cis-permethrinate were synthesized. Their insecticidal activities were tested and the fluorine effect of title compounds was discussed.
- Zou, Xinzhuo,Qiu, Zongxing
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p. 173 - 179
(2007/10/03)
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- An improved synthetic procedure for 6,6′-dibromoindigo (Tyrian purple)
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Tyrian purple was the most precious dye of antiquity. We describe a simple synthetic procedure that yields the actual dye, 6,6′-dibromoindigo 1, in considerably improved overall yield and of analytical purity, also being amenable to scale-up.
- Imming,Imhof,Zentgraf
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p. 3721 - 3727
(2007/10/03)
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- An oxidative transformation of N′-phenylhydrazide to t-butyl ester using a copper(II) halide-lithium t-butoxide system
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Reactions of hydrazides or N1-phenylhydrazides with a copper(II) reagent prepared from copper(II) bromide and lithium t-butoxide smoothly proceeded to give the corresponding t-butyl ester in high yield.
- Yamaguchi, Jun-Ichi,Aoyagi, Takashi,Fujikura, Ryohei,Suyama, Takayuki
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p. 466 - 467
(2007/10/03)
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- ipso Nitration. XXVII. The crystal structure and stereochemistry of 3-bromo-6-methyl-6-nitrocyclohexa-2,4-dienyl acetate, 5-bromo-2-methyl-6-nitrocyclohexa-2,4-dienyl acetate, and 3-bromo-6-methyl-6-nitrocyclohexa-2,4-dienyl chloride
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The adduct obtained on nitration of 4-bromotoluene in acetic anhydride is (Z)-3-bromo-6-methyl-6-nitrocyclohexa-2,4-dienyl acetate.Its stereoselective rearrangement product, obtained on thermolysis in the presence of p-cresol, is (Z)-5-bromo-2-methyl-6-nitrocyclohexa-2,4-dienyl acetate.Reaction with hydrogen chloride in ether is also stereospecific and gives (Z)-3-bromo-6-methyl-6-nitrocyclohexa-2,4-dienyl chloride.The crystal structures of these compounds are reported.
- Bushnell, Gordon W.,Fischer, Alfred,Henderson, George N.,Mahasay, Sumit Ray
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p. 2382 - 2387
(2007/10/02)
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- Synthesis and some reactions of 6-bromooxindole
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An efficient synthesis of 4- and 6-bromooxindoles, previously unknown compounds, from 6- and 4-amino-2-nitrotoluenes and the transformation of 6-bromooxindole to 3-acylated derivatives are described.
- Kosuge,Ishida,Inaba,Nukaya
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p. 1414 - 1418
(2007/10/02)
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- ipso-Nitration: Formation of Nitronium Acetate Adducts in the Nitration of p-Acetamido-, p-Halogeno-, and p-Methoxy-toluenes, and α-p-Tolyloxyisobutyric acid
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Low-temperature nitration of the title compounds in acetic anhydride gives 1,2-nitronium acetate adducts, except p-fluorotoluene which gives both 1,2 and 1,4 adducts and α-p-tolyloxyisobutyric acid which gives a spiro adduct.
- Fischer, Alfred,Fyles, Deborah L.,Henderson, George N.
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p. 513 - 514
(2007/10/02)
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