1131-40-4Relevant academic research and scientific papers
Characterization of a Cyanobacterial Haloperoxidase and Evaluation of its Biocatalytic Halogenation Potential
Frank, Annika,Seel, Catharina Julia,Groll, Michael,Gulder, Tanja
, p. 2028 - 2032 (2016)
Vanadium-dependent haloperoxidases (VHPOs) are a class of halogenating enzymes found in fungi, lichen, algae, and bacteria. We report the cloning, purification, and characterization of a functional VHPO from the cyanobacterium Acaryochloris marina (AmVHPO), including its structure determination by X-ray crystallography. Compared to other VHPOs, the AmVHPO features a unique set of disulfide bonds that stabilize the dodecameric assembly of the protein. Easy access by high-yield recombinant expression, as well as resistance towards organic solvents and temperature, together with a distinct halogenation reactivity, make this enzyme a promising starting point for the development of biocatalytic transformations.
Molybdenum(VI) amino triphenolate complexes as catalysts for sulfoxidation, epoxidation and haloperoxidation
Romano, Francesco,Linden, Anthony,Mba, Miriam,Zonta, Cristiano,Licini, Giulia
, p. 2937 - 2942 (2010)
Two molybdenum(VI) complexes bearing a C3 symmetrical amino tris-tert-butylphenolate ligand have proved to be air- and water-tolerant catalysts that efficiently catalyse, in high yields and selectivity, the oxidation of sulfides, olefins and halides. In particular high turnover frequencies and turnover numbers (TOF and TON) have been obtained for the cyclooctene epoxidation (catalyst loading down to 0.05%, TONs up to 88,000 and TOFs up to 7500h-1). Copyright
Regioselective Oxybromination of Benzene and Its Derivatives by Bromide Anion with a Mononuclear Nonheme Mn(IV)-Oxo Complex
Sharma, Namita,Lee, Yong-Min,Li, Xiao-Xi,Nam, Wonwoo,Fukuzumi, Shunichi
, p. 14299 - 14303 (2019)
Oxybromination of aromatic compounds by high-valent metal-oxo intermediates has yet to be explored despite extensive studies on the oxybromination of aliphatic C-H bonds of hydrocarbons. Herein, we report the regioselective oxybromination of methoxy-substituted benzenes by a nonheme MnIV-oxo complex binding scandium ions, [(Bn-TPEN)MnIV(O)]2+-(Sc(OTf)3)2 (1), in the presence of tetrabutylammonium bromide. The regioselective oxybromination occurs at the carbon atom with the highest positive charge via electron transfer (ET) from the methoxy-substituted benzenes to 1. ET driving force dependence of the rate constants of ET from methoxy-substituted benzenes to 1 is well fitted in light of the Marcus theory of ET. Under photoirradiation, the oxybromination of benzene by 1 can be achieved via ET from benzene to the photoexcited state of 1, although no reaction occurs between benzene and the ground state of 1 in the dark. To the best of our knowledge, this is the first example of reporting the stoichiometric regioselective oxybromination of the benzene ring by a synthetic high-valent Mn(IV)-oxo complex and the catalytic regioselective oxybromination reaction with a Mn(II) complex and a terminal oxidant.
Discrete spherical hexadecavanadates incorporating a bromide with oxidative bromination activity
Kato, Naohiro,Hayashi, Yoshihito
, p. 11804 - 11811 (2013)
Two discrete hexadecavanadates, (n-Bu4N)4[V 16O38(X)] (X = Cl- (1) and X = Br- (2)), were synthesized by a reaction of [V10O26] 4- with a template anion resulting in the incorporation of chloride or bromide in the {V16} spherical cluster framework. The reaction of [V 10O26]4- with p-toluenesulfonic acid proceeded under an aerobic environment to give 2 in the presence of an excess amount of bromide anion, which acted as both a template anion and a reducing reagent for the formation of the mixed-valence framework. For the synthesis of cluster 1, additional reductive conditions were required due to the weak reducing ability of the chloride anion. The crystal structures of 1 and 2 were determined using single-crystal X-ray diffraction analysis. Both were found to consist of a discrete [VV9VIV7O 38(X)]4- framework by the linkage of VO5 pyramidal units. Cyclic voltammetric studies of 1 and 2 in acetonitrile showed a series of stepwise reversible redox processes, which were due to the redox of the spherical polyoxovanadate frameworks. The oxidative bromination reactions of aromatic substrates were also investigated using cluster 2 as a catalyst under aerobic conditions. The Royal Society of Chemistry.
Oxidative bromination reactions in aqueous media by using Bu4NBr/TFA/H2O2 system
Moriuchi, Toshiyuki,Fukui, Yasuhiro,Sakuramoto, Takashi,Hirao, Toshikazu
, p. 1708 - 1710 (2017)
Metal-free oxidative bromination reactions in aqueous media were performed using tetrabutylammonium bromide, trifluoroacetic acid, and hydrogen peroxide under mild conditions. Oxidative bromination reaction of alkenes was found to afford the corresponding vic-bromides. Furthermore, this oxidative bromination system is applicable to the oxidative bromination of alkynes, arenes, and 3,4-dihydronaphthalen-1(2H)-one. A gram-scale bromination reaction was also performed successfully.
Indole-Catalyzed Bromolactonization in Lipophilic Solvent: A Solid-Liquid Phase Transfer Approach
Chen, Tao,Foo, Thomas Jian Yao,Yeung, Ying-Yeung
, p. 4751 - 4755 (2015)
We have developed a novel indole-catalyzed bromolactonization of olefinic acids. The reaction could be conducted in lipophilic solvent through a solid-liquid phase transfer mechanism. This catalytic protocol has been applied to the synthesis of base-sensitive bromolactones. (Chemical Equation Presented).
Additive-Free Copper(I)-Mediated Synthesis of 5- or 6-Brominated 2-Aryl-1 H-Indole-3-Carboxylates from α,α-Dibromo β-Iminoesters
Li, Zhenfa,Zhao, Lan,Liang, Liuyi,Zhao, Lixin,Li, Fangyi,Wang, Chunhua,Li, Zheng
, p. 1964 - 1971 (2021)
Additive-free copper(I)-bromide-mediated radical cyclization reactions of α,α-dibromo β-iminoesters were investigated, enabling the synthesis of a series of 5- or 6-brominated 2-aryl-1H-indole-3-carboxylates in moderate to good yields. The mechanistic study showed that (i) the bromine atom originated from the substrates and (ii) the bromination might be related to a 3-bromo-3H indole intermediate via an electrophilic bromine atom transfer. Furthermore, the practicality of this method was demonstrated by gram-scale synthesis and the potential for product derivatization toward other valuable multisubstituted indoles.
Bromination of phenyl ether and other aromatics with bromoisobutyrate and dimethyl sulfoxide
Li, Jia-Qin,Chen, Xiao-Hui,Wang, Xian-Xun,Cui, Hai-Lei
supporting information, (2021/09/09)
Bromoisobutyrate has been used for the first time as a general brominating source for the direct bromination of a diverse of simple phenyl ethers. Aromatic ethers bearing various substituents could be compatible in this reaction system delivering brominated arenes in moderate to good yields. The reaction system can also be expanded to bromination of phenols and unactivated arene. This process can be regarded as an alternative for the well-established bromination systems for bromoarene synthesis.
Hydrogen-Bond-Donor Solvents Enable Catalyst-Free (Radio)-Halogenation and Deuteration of Organoborons
Yang, Yi,Gao, Xinyan,Zeng, Xiaojun,Han, Junbin,Xu, Bo
supporting information, p. 1297 - 1300 (2020/12/23)
A hydrogen bond donor solvent assisted (radio)halogenation and deuteration of organoborons has been developed. The reactions exhibited high functional group tolerance and needed only an ambient atmosphere. Most importantly, compared to literature methods, our conditions are more consistent with the principals of green chemistry (e.g., metal-free, strong oxidant-free, more straightforward conditions).
Stepwise mechanism for the bromination of arenes by a hypervalent iodine reagent
Arrieta, Ana,Cossío, Fernando P.,Granados, Albert,Shafir, Alexandr,Vallribera, Adelina
, p. 2142 - 2150 (2020/03/11)
A mild, metal-free bromination method of arenes has been developed using the combination of bis(trifluoroacetoxy)iodobencene and trimethylsilyl bromide. In situ-formed dibromo(phenyl)-λ3-iodane (PhIBr2) is proposed as the reactive intermediate. This methodology using PIFA/TMSBr has been applied with success to a great number of substrates (25 examples). The treatment of mono-substituted activated arenes led to para-brominated products (2u-z) in excellent 83-96% yields. Density functional theory calculations indicate a stepwise mechanism involving a double bromine addition followed by a type II dyotropic reaction with concomitant re-aromatization of the six-membered ring.
