Monobromination of Activated Aromatic Compounds with Polyvinylbenzyltriphenylphosphonium Supported Tribromide

Chloromethylated crosslinked co‐polyvinylbenzene‐divinylbenzene (2% DVB) was treated with triphenylphosphine and then with sodium bromate and hydrobromic add to afford red colored insoluble polyvinylbenzyltriphenylphosphonium supported tribromide. This reagent could be used as a mild and efficient monobrominating reagent for activated aromatic compounds such as phenols, aromatic ethers, aromatic amines and acetylanilines with good yields and high para‐selectivity.     

Regioselective Bromination of Aromatic Amines and Phenols Using N-Benzyl-DABCO Tribromide

N-Benzyl-DABCO tribromide, a stable, solid organic ammonium tribromide, has been used as a bromine source for the regioselective and high-yielding bromination of aromatic amines and phenols. Mono-bromination proceeds well in the presence of a stoichiometric amount of bromine source at room temperature.     

Practical and Regioselective Halogenations of Aromatic Compounds Using Tetrabutylammonium Peroxydisulfate

Abstract

The halogenated aromatic compounds have been important intermediates for various synthetic methods. Electron-rich aromatic compounds were easily iodinated using tetrabutylammonium peroxydisulfate (1) and iodine in mild conditions with excellent yields. Bromination was achieved using 1 and bromine, and regioselective bromination of highly activated aromatic compounds was also achieved using 1 and lithium bromide in mild conditions with excellent yields.     

Urea Nitrate : A Reagent for Regioselective Nitration of Aromatic Amines

Nitration o f the aromatic amines with urea nitrate in sulphuric acid gave exclusively the p-isomer and when the p-position is blocked, the nitration occurred to give a m-nitroaniline derivative in excellent yields. However, nitration was not effected at o-position. Mechanistic aspect of this reaction is also discussed.     

Regioselective Photochemical and Microwave Mediated Monobromination of Aromatic Compounds using 2,4,4,6–Tetrabromo‐2,5‐cyclohexadienone

Bromination of different aromatic substrates have been described using 2,4,4,6‐tetrabromo‐2,5‐cyclohexadienone in conjunction with microwave and ultraviolet radiations. Important features of the work include high regioselectivity obtained in very short to moderate reaction time, atom economy, and recyclability of the reagent.     

Facile Synthesis of 1,5-Benzothiazepines in Water Using Tetrabutylammonium Tribromide

Abstract

A simple, environmentally benign, and efficient method was developed for the preparation of 1,5-benzothiazepines via a one-pot condensation reaction of 2-aminothiophenol with 1,3-diaryl- 2-propenones using tetrabutylammonium tribromide as an efficient and versatile catalyst in water.     

Solvent Incorporation in Bromination of Alkynes With Tetrabutylammonium Tribromide in Methanol

ABSTRACT: The reaction of tetrabutylammonium tribromide (TBABr₃) with mono and disubstituted alkynes in methanol at 20°C leads to the formation of mainly the corresponding α,α-dibromo, β,β-dimethoxyalkane and the E-(α,β)-dibromoalkene. The additions are faster using sonication.     

Regioselective Aromatic Monobromination of Alkyl Phenyl Ethers with NaClO2, NaBr,Mn(acac)3, and Montmorillonite K10 in Dichloromethane

Regioselective and high-yielding nuclear monobromination of aromatic ethers can be accomplished with a combination of NaClO₂, NaBr, and Mn(acac)₃ catalyst in dichloromethane under mild and neutral conditions with the aid of Montmorillonite K10.     

芳香化合物在碘或碘化铵催化作用下的单溴代反应

研究了芳香化合物在碘或碘化铵催化作用下的单溴代选择性反应, 该反应是经过有机高价碘中间体进行的. 通过该反应, 富电子芳香化合物在碘或碘化铵催化作用下很容易与溴化钾、 间氯过氧苯甲酸、 对甲苯磺酸和少量苯的混合物发生反应, 常温下短时间内得到产率良好并具有区域选择性的单溴代芳香化合物. 考察了反应条件的影响, 提出了可能的反应机理, 为简单快速合成单溴代芳香化合物提供了新方法.     

Reaction of Aminoethynylphosphonates with Primary Aromatic Amines

Addition of primary aromatic amines to aminoethynylphosphonates proceeds chemo-and regio-selectively without an acidic catalyst and affords unsymmetrical phosphonoacetamidines. The probable reaction mechanism involves amine addition followed by prototropic isomerization. The method described extends the range of synthetic approaches to various unsymmetrical phosphorylated amidines. Reaction of the starting aminoethynylphosphonates with primary aliphatic amines possessing bulky substituents results in quantitative formation of the corresponding diaminoethynylphosphonates. The structure of the obtained compounds was proved by ¹H, ¹³C, and ³¹P NMR spectroscopy.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 1, 2005, pp. 5–10.Original Russian Text Copyright © 2005 by Panarina, Aleksandrova, Dogadina, Ionin.     

Kinetics and Mechanism of Oxidation of Hydroquinone by Tetrabutylammonium Tribromide Ion in Aqueous Acetic Acid

The oxidation of hydroquinone by environmentally benign tetrabutyl ammonium tribromide (TBATB) was carried out in 50% V/V aqueous acetic acid medium under pseudo-first-order conditions, keeping a large excess of hydroquinone over the oxidant. The main reactive species of oxidant and substrate were found to be the Br₃^-\mathrm{Br}_{3}^{-} ion and hydroquinone, respectively. The reaction proceeds with prior complex formation between the reactants followed by its slow decomposition to generate semiquinone and bromine radicals. The complex formation was kinetically verified by its Michaelis–Menten plot. The solvent effect was verified by using Grunwald–Winstein equation which is consistent with an S_N2 mechanism. The formation constants for the complex and rate constant for the slow decomposition step were determined by studying the reaction at five different temperatures. The values of formation constant of the complex and the rate constant for its decomposition were determined at these temperatures. The activation parameters with respect to the slow step of the reaction have also been determined.     

Derivatizat Ion of Primary Aromatic Amines with Fluorescamine

Abstract

Fluorescamine forms stable, fluorescent derivatives with sterically-unhindered primary aromatic amines in both aqueous (borate buffer, pH 9/acetonitrile) and nonaqueous (pyridine/-acetonitrile) media. Aromatic amines with a substituent such as a methyl group or an aromatic ring ortho to the amine functionality either derivatized poorly or not at all because of steric hindrance.     

Nucleophilic Functionalization of Tropylium Salts with Aromatic Amines

Russian Journal of Organic Chemistry - The mini-review systematizes recently published data on nucleophilic N- and C-amination of electron-deficient tropylium salts with aromatic amines.     

对-甲苯乙酮与芳香醛和芳香胺的Mannich反应

Mannich反应是合成新化合物的重要方法 [1] ,其对应的产物 Mannich碱常常具有广泛的生物活性 [2 ] .文献报道 ,对 -甲苯乙酮的 Mannich碱具有抑癌 [3]和麻醉拮抗 [4 ]等生物活性 ,但是文献中对 -甲苯乙酮 Mannich碱的合成却是从胺交换法 [5] 、酮交换法 [6] 、查耳酮与胺的 Michael加成[7] 、Schiff碱与酮的缩合 [8～ 14 ] 、β-内酰胺与有机锂的亲核裂解 [15] 等间接方法得到的 .即使是从直接法合成 ,一般也是甲醛参与的 Mannich反应 .虽然芳香醛和芳香胺同时参与的 Mannich反应已有报道 [16] ,但对 -甲苯乙酮与芳香醛和芳香胺直接进行…     

Iodination of Aromatic Amines with Iodine and Silver Sulfate

Iodination of aromatic amines with iodine / silver sulfate at room temperature gives iodo-products in good (46-96%) yield.     

The Reaction of Electron-Deficient Cyclopropane Derivatives with Aromatic Amines

Abstract

N-Aryl-trans,trans-α-carboxyl-β-benzoyl-γ-aryl-γ-butyrolactams were synthesized in high yields with high stereoselectivity by the reaction of electron-deficient cyclopropane derivatives, cis-1-benzoyl-2-aryl-6,6-dimethyl-5,7-dioxo-spiro-[2 (a) Zhang , J. ; Blazecka , P. G. ; Davidson , J. G. First direct reductive amination of mucochloric acid: A simple and efficient method for preparing highly functionalized α,β-unsaturated γ-butyrolactams . Org. Lett. 2003 , 5 , 553 – 556 ; (b) Sarma, K. D.; Zhang, J.; Curran, T. T. Novel synthons from mucochloric acid: The first use of α,β-dichloro-γ-butenolides and γ-butyrolactams for direct vinylogous aldol addition. J. Org. Chem. 2007, 72, 3311–3318 . [Google Scholar] 5 (a) Chen , Y. L. ; Ding , W. Y. A simple approach to highly stereoselective synthesis of β γ-trans-γ-butyrolactones . Chem. J. Chin. Univ. 1998 , 19 , 1614 – 1616 ; (b) Chen, Y. L.; Ding, W. Y.; Cao, W. G.; Lu, C. Stereoselective synthesis of N-aryl-trans,trans-α-carboxyl-β-methoxycarbonyl-γ-aryl-γ-butyrolactones. Synth. Commun. 2002, 32, 1953–1960.  [Google Scholar]]-4,8-octadiones, with aromatic amines. The reaction mechanism was proposed.     

Photoredox Catalyzed Dealkylative Aromatic Halogen Substitution with Tertiary Amines

A reaction of aromatic halides bearing electron-withdrawing groups with tertiary amines in the presence of an iridium catalyst under blue light irradiation is described. Products of the aromatic substitution of the halide by the dialkylamino fragment are obtained. The interaction of aryl radicals with tertiary amines to generate zwitterionic radical species is believed to be the key factor responsible for the reaction efficiency.