Dibromoisocyanuric Acid Research Articles

CsPbBr3 in the Activation of the C–Br Bond of CBrX3 (X = Cl, Br) under Sunlight

A newly synthesized green-fluorescent, orthorhombic, bromide-rich, perovskite nanocrystal (Φ ∼ 0.93, τ ∼ 12.5 ns, Eox = +1.6 V) obtained from an unprecedented bromide precursor dibromoisocyanuric acid was found to be an excellent visible-light (sunlight or blue-light-emitting diode (LED)) photocatalyst toward the synthesis of gem-dihaloenones for the first time. The photoactivated CsPbBr3 catalyzed the homolytic cleavage of CBrX3 (X = Cl, Br) to generate the •CX3 radical, which underwent cascaded C–C cross-coupling with terminal alkynes into the corresponding gem-dihaloenones. Radical-trapping experiments and luminescence-quenching studies helped establish a single-electron-transfer (SET) mechanism. Interestingly, other highly stable CsPbBr3 NCs, obtained from N-bromosuccinimide (NBS) and dibromohydantoin (DBHT) precursors, are unable to carry out these transformations. These results not only enrich the CsPbBr3 synthetic methodology but also encourage the research community to develop efficient and cost-effective photocatalytic materials.

Novel energetic furazans containing isomeric N-(azoxy)-dinitropyrazole moieties: Synthesis, characterization and comparison of properties

Novel energetic furazans 3a–3c and 4a–4c containing isomeric (3,4-dinitro-1H-pyrazol-1-yl)-NNO-azoxy and (3,5-dinitro-1H-pyrazol-1-yl)-NNO-azoxy moieties have been obtained. A synthetic approach to aminofurazans 3a and 4a involves the reaction of 1-amino-3,4-dinitro-1H-pyrazole or 1-amino-3,5-dinitro-1H-pyrazole with 2,2,2-trifluoro-N-(4-nitrosofurazan-3-yl)acetamide and dibromoisocyanuric acid, followed by removal of the trifluoroacetyl group. Transformations of the amino group in aminofurazans 3a and 4a gave the corresponding nitro (3b, 4b) and azo (3c, 4c) substituted furazans. The compounds synthesized exhibit high experimental enthalpies of formation (2093–2847 kJ·kg−1), good thermal stabilities (onset decomposition temperatures 203–228 °C), acceptable densities (1.78–1.87 g·cm−3) and high detonation parameters (detonation velocities D = 8.71–8.99 km s−1, detonation pressures p = 33.9–38.7 GPa). Nitro substituted furazans 3b, 4b and azo substituted furazans 3c, 4c have been evaluated as effective energetic fillers for solid composite propellants, providing specific impulse values 9–11 s higher than similar formulations based on RDX and HMX, and 4–6 s higher than similar formulations based on CL-20.

CsPbBr3 perovskite quantum dots as a visible light photocatalyst for cyclisation of diamines and amino alcohols: an efficient approach to synthesize imidazolidines, fused-imidazolidines and oxazolidines

We report the synthesis of highly stable CsPbBr3QD based photocatalysts using dibromoisocyanuric acid (DBI) as a benign non-toxic bromide precursor.

Facile one-pot synthesis of ketones from primary alcohols under mild conditions

One-pot transformation of primary alcohols to ketones was achieved by using dibromoisocyanuric acid and Fe2O3. This synthetic method provides a variety of ketones in high yield under mild reaction conditions.

Dibromoisocyanuric Acid: Applications in Brominations and Oxidation Processes for the Synthesis of High Value Compounds

AbstractIn recent years, synthetic chemists continue to search for new methodologies to access organic molecules of value. Bromine containing molecules persist to yield interesting discoveries when employed in new (and known) transformations. Whilst a plethora of bromine containing compounds exist in the literature at a chemist's disposal for organic synthesis, this minireview will pay close attention to one of the more understudied reagents in comparison, dibromoisocyanuric acid (DBI) (and its closely related mono‐ or tri‐ bromo derivatives). The scope of this minireview looks to explore the most recent implementations of DBI and its derivatives over the period of 2015–2020, looking closely at its uses in organic transformations, employed as a brominating reagent in dye syntheses amongst other applications.

Decarboxylative Tribromination for the Selective Synthesis of Tribromomethyl Ketone and Tribromovinyl Derivatives

AbstractTribromomethyl ketone and tribromovinyl derivatives were selectively prepared from the decarboxylative tribromination. The reaction between propiolic acid derivatives and dibromoisocyanuric acid (DBCA)/H2O afforded predominantly a tribromomethyl ketone derivative in the presence of AgOAc (10 mol%). When the same reaction was conducted with 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) instead of AgOAc, tribromovinyl derivatives were exclusively formed in good yields. It was found that ethynyl bromide is an intermediate.magnified image

Convenient metal-free direct oxidative amidation of aldehyde using dibromoisocyanuric acid under mild conditions

A facile method for the direct synthesis of amides from aldehydes is described. Amide bonds were synthesized by an oxidative amidation in the presence of dibromoisocyanuric acid (DBI). Treatment of aromatic and aliphatic aldehydes with dibromoisocyanuric acid generated acyl bromide intermediates, which were employed to react with a variety of secondary and primary amines to give amides. Through this reaction method, various amides were synthesized directly from aldehydes under mild conditions in high yields and short times. This facile and efficient procedure provides potential strategy for the direct synthesis of amides from aldehydes.

Aerobic oxidative esterification and thioesterification of aldehydes using dibromoisocyanuric acid under mild conditions: no metal catalysts required

Esters and thioesters were successfully prepared through oxidative esterification and thioesterification of corresponding aldehydes in the presence of dibromoisocyanuric acid.

Silver-Catalyzed Decarboxylative Bromination of Aliphatic Carboxylic Acids

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.

ChemInform Abstract: Boronic Acid‐Catalyzed Selective Oxidation of 1,2‐Diols to α‐Hydroxy Ketones in Water.

AbstractVarious 1,2‐diols are selectively oxidized to α‐hydroxyketones via their boronate esters using dibromoisocyanuric acid as the terminal oxidant or an electrochemical oxidation.

Superior bactericidal activity of N-bromine compounds compared to their N-chlorine analogues can be reversed under protein load.

To investigate and compare the bactericidal activity (BA) of active bromine and chlorine compounds in the absence and presence of protein load. Quantitative killing tests against Escherichia coli and Staphylococcus aureus were performed both in the absence and in the presence of peptone with pairs of isosteric active chlorine and bromine compounds: hypochlorous and hypobromous acid (HOCl and HOBr), dichloro- and dibromoisocyanuric acid, chlorantine and bromantine (1,3-dibromo- and 1,3 dichloro-5,5-dimethylhydantoine), chloramine T and bromamine T (N-chloro- and N-bromo-4-methylbenzenesulphonamide sodium), and N-chloro- and N-bromotaurine sodium. To classify the bactericidal activities on a quantitative basis, an empirical coefficient named specific bactericidal activity (SBA), founded on the parameters of killing curves, was defined: SBA= mean log reductions/(mean exposure times x concentration) [mmol 1(-1) min (-1)]. In the absence of peptone, tests with washed micro-organisms revealed a throughout higher BA of bromine compounds with only slight differences between single substances. This was in contrast to chlorine compounds, whose killing times differed by a factor of more than four decimal powers. As a consequence, also the isosteric pairs showed according differences. In the presence of peptone, however, bromine compounds showed an increased loss of BA, which partly caused a reversal of efficacy within isosteric pairs. In medical practice, weakly oxidizing active chlorine compounds like chloramines have the highest potential as topical anti-infectives in the presence of proteinaceous material (mucous membranes, open wounds). Active bromine compounds, on the other hand, have their chance at insensitive body regions with low organic matter, for example skin surfaces. The expected protein load is one of the most important parameters for selection of a suited active halogen compound.

Boronic Acid‐Catalyzed Selective Oxidation of 1,2‐Diols to α‐Hydroxy Ketones in Water

AbstractThe activation of 1,2‐diols through formation of boronate esters was found to enhance the selective oxidation of 1,2‐diols to their corresponding α‐hydroxy ketones in aqueous medium. The oxidation step was accomplished using dibromoisocyanuric acid (DBI) as a terminal chemical oxidant or an electrochemical process. The electrochemical process was based on the use of platinum electrodes, methylboronic acid [MeB(OH)2] as a catalyst and bromide ion as a mediator. Electro‐generated OH− ions (EGB) at the cathode acted as a base and “Br+” ion generated at the anode acted as an oxidant. Various cyclic and acyclic 1,2‐diols as substrates were selectively oxidized to the corresponding α‐hydroxy ketones via their boronate esters by the two oxidative methods in good to excellent yields.magnified image

An efficient method for selective oxidation of 1,2-diols in water catalyzed by Me2SnCl2

Dimethyltin(IV)dichloride-catalyzed selective oxidation of 1,2-diols in water was achieved using dibromoisocyanuric acid (DBI) or Br2 as oxidants. The catalyst activates the 1,2-diol moiety through the formation of stannylene acetal in addition to enhancing selectivity. Various cyclic and acyclic 1,2-diol substrates have been selectively oxidized affording α-hydroxyketones in good to excellent yields. This method is safe and simple in operation.

Bis(nitro- and polynitromethyl-ONN-azoxy)azoxyfurazans and some of their derivatives

Reaction of diamino derivative of azoxyfurazan with 2,2-dimethyl-5-nitro-5-nitroso-1,3-dioxane in the presence of dibromoisocyanuric acid afforded bis(2,2-dimethyl-5-nitro-1,3-dioxan-5-yl-ONN-azoxy)azoxyfurazan. The reaction of the latter with AcCl/MeOH and further transformations of the product gave the first representative of substituted (mono- and polynitroalkyl-ONN-azoxy)azoxyfurazans, e.g. bis(nitromethyl-ONN-azoxy)azoxyfurazan, bis(dinitromethyl-ONN-azoxy)azoxyfurazan, bis(trinitromethyl-ONN-azoxy)azoxyfurazan, and some of their derivatives.

ChemInform Abstract: Reaction of 1,1-Disubstituted Hydrazines with Dibromoisocyanuric Acid in the Presence of Nitrosobenzene.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Dibromination of 5‐pyrazolones and 5‐hydroxypyrazoles via dibromoisocyanuric acid

Abstract magnified image A safe and efficient method was developed for the dibromination of pyrazolones and 5‐hydroxypyrazoles by use of dibromoisocyanuric acid (DBI). The reaction gave the corresponding dibrominated pyrazolones in excellent yields (≥91%). J. Heterocyclic Chem., (2010).

Core-Tetrasubstituted Naphthalene Diimides: Synthesis, Optical Properties, and Redox Characteristics

2,3,6,7-tetrabromonaphthalene dianhydride has been synthesized by the bromination of naphthalene dianhydride with dibromoisocyanuric acid in excellent yield. The condensation of this dianhydride with 2,6-diisopropylaniline yielded the corresponding tetrabromo-substituted naphthalene diimide (NDI), which is a versatile precursor for the synthesis of core-tetrafunctionalized NDIs. Nucleophilic substitution of tetrabromo NDI with alkoxy, alkylthio, and alkylamino nucleophiles afforded a series of core-tetrasubstituted NDI chromophores that complete the series of previously reported di- and trifunctionalized NDI derivatives. The effects of electronic nature and number of core substituents on the optical and electrochemical properties of NDIs have been investigated by UV-vis and fluorescence spectroscopy and cyclic voltammetry. The absorption maxima (629-642 nm) of tetraamino NDIs are strongly bathochromically shifted compared to those of other core-functionalized NDIs.

Multisubstituted phthalonitriles for phthalocyanine synthesis

3,4,5,6-tetrafluorophthalonitrile and 3,4,5,6-tetrachlorophthalonitrile were used as substrates with various phenoxides to prepare 3,4,6-trihalo-5-p-substitutedphenoxyphthalonitriles, containing four substituents other than hydrogen, by nucleophilic aromatic substitution reactions. Subsequent reactions with unsymmetrical catechols gave tetrasubstitutedphthalonitriles, having four different substituents. In one instance, attempts to displace the last remaining fluoro group by an octanoxide nucleophile led to substitution of a p-methylphenoxy group, showing that phenoxy substituents are also labile in nucleophilic aromatic substitution reactions on phthalonitriles. Alternatively, 4,5-dimethoxyphthalonitrile or 4,5-dineopentoxyphthalonitrile underwent electrophilic aromatic substitution reactions with dibromoisocyanuric acid to give their respective 3,6-dibromophthalonitriles. Coupling of these bromophthalonitriles with tri(n-butyl)phenylylethynyltin and tri(n-butyl)vinyltin in the presence of a nickel catalyst gave 4,5-dimethoxy-3,6-bisphenylethy nylphthalonitrile, 3-bromo-4,5-dimethoxy-6-phenylethynylphthalonitrile, 4,5-dineopentoxy-3,6-bisphenylethynylphthalonitrile, 3-bromo-4,5-dineopentoxy-6-phenylethynylphthalonitrile, 4,5-dimethoxy-3,6-vinylphthalonitrile and 3-bromo-4,5-dimethoxy-6-vinylphthalonitrile. Reductions in the coupling steps sometimes led to 4,5-dimethoxy-3-phenylethynylphthalonitrile and 4,5-dimethoxy-3-vinylphthalonitrile.

Bromination of Isoquinoline, Quinoline, Quinazoline and Quinoxaline in Strong Acid

Bromination of benzazines and benzodiazines most often gives a mixture of products. In this paper, we show that isoquinoline (1) may be regioselectively monobrominated in concentrated H2SO4 using NBS or in CF3SO3H using N,N’-dibromoisocyanuric acid (DBI) to give 5-bromoisoquinoline (2). The bromination was found to be highly sensitive to the choice of brominating agent, acid, temperature and concentration. Quinoline, quinazoline and quinoxaline may be brominated likewise, although with the strong regioselectivity reserved to isoquinoline.

Nitration and Bromination of Benzo‐1,2,3,4‐tetrazine 1,3‐Dioxides.

Benzo-1,2,3,4-tetrazine 1,3-dioxide (BTDO) and its derivatives were nitrated with HNO3/H2SO4 or HNO3/oleum and brominated with dibromoisocyanuric acid in CF3CO2H/H2SO4 (5 : 1) or H2SO4. The reactivity of positions in the benzene ring of this heterocyclic system as regards electrophilic substitution was found to change in the following order: 5 ≈ 7 > 8 > 6. Mono- and dinitro-BTDOs and mono- and polybromo-BTDOs were synthesized. Their structures were confirmed by 1H, 13C, and 14N NMR spectra.