Alkyl Dibromides Research Articles

Synthesis, structure elucidation, Hirshfeld surface analysis, DFT, and molecular docking of new 6-bromo-imidazo[4,5-b]pyridine derivatives as potential tyrosyl-tRNA synthetase inhibitors

Novel 6-bromo-imidazo[4,5-b]pyridine derivatives (2-4, 5a-13a, and 6b, 8b-13b) have been synthesized based on a developed systematic approach involving the condensation of 5-Bromo-2,3-diaminopyridine with a suitable aromatic aldehyde in the presence of molecular iodine in water, followed by alkylation reactions using different alkyl dibromide agents. The synthesized compounds were characterized by the NMR spectroscopy technique. The structures of 8a, 9a, 12a, and 11b were confirmed using monocrystalline X-ray crystallography. Theoretical calculations have been carried out using DFT and TD-DFT methods at the B3LYP/6-31G++(d,p) level of theory. Intermolecular contacts between units of 8a, 9a, 12a, and 11b were determined through the Hirshfeld surface analysis. The molecular docking study has been performed to determine the binding affinity of 8a, 9a, 12a, and 11b into the binding site of S. aureus tyrosyl-tRNA synthetase as a target enzyme, and the results revealed that 9a is the most potent compound among the selected compounds with a binding affinity of −8.74 Kcal/mol. Communicated by Ramaswamy H. Sarma

C(sp3)–C(sp3) coupling polymerization of alkyl dibromides for preparation of polymers with precisely located phenyl pendants

Recently it was reported that C(sp3)Br–C(sp3)Br homo-coupling reactions may be occurred efficiently catalyzed by Ni(II) in the presence of Zn. In this work, we applied this reaction for polymerization of alkyl dibromides. It was shown that 1,4-dibromobutane may polymerize by this coupling polymerization to afford polybutenes with low molecular weight. Then dl-1,4-dibromo-2,3-diphenylbutane, 1,3-dibromo-2-phenylpropane and dl-1,4-dibromo-2-phenylbutane were polymerized by the C(sp3)–C(sp3) coupling reaction under optimized condition. As a result, head-to-head polystyrene, poly(methylene-alt-styrene), and poly(ethylene-alt-styrene) were obtained. The number average molecular weights relatively to polystyrene standards may reach ca. 6000 Da. These polymers with strictly controlled sequential structures were characterized by proton and carbon nuclear magnetic resonance spectroscopy and matrix-assisted laser-desorption-ionization time-of-flight mass. Glass transition temperature was obtained by running differential scanning calorimetry.

One-step synthesis of poly(triazole-ether-quinoxaline)s using click reaction: preparation and properties of magnetic nanocomposites with modified Fe3O4 for metal ions removal

A new dialkyne-terminated monomer, 2,3-bis(4-(prop-2-yn-1-yloxy)phenyl)quinoxaline, was synthesized and used in the click reaction with various alkyl dibromides by a convenient one-pot procedure to yield poly(triazole-ether-quinoxaline)s (PTAEQ). The weight average molecular weights (Mw) of PTAEQs were measured by GPC and were in the range of 1.87×104–2.41×104 g/mol. These polymers exhibited Tg and 10 % weight loss temperatures (T10%) in the range of 177–262 °C and 350–420 °C, respectively. PTAEQs showed excellent solubility in various polar organic solvents and formed low-colored and tough thin films via solution casting. A series of nanocomposites was prepared from solution blending of PTAEQs with epoxide-end capped Fe3O4 nanoparticles. Structure and morphology of the prepared magnetic nanocomposites (MNCPTAEQ)s were investigated, and the effect of interfacial adhesion between organic and inorganic phases on thermal, solubility, mechanical and optical properties of composites was investigated. The functional sites in the polymer chains were also tested for the removal of toxic metal ions such as Cr3+, Pb2+, Cd2+, Sn2+, Cu2+ and Hg2+ from aqueous solutions either individually or in the mixture.

Six cation-templated halometal complexes and C–H activation of alkylene-bridged azoles

Six dication-templated complexes were discovered in efforts to investigate the effect of linear imidazolium-based template, 1,ω-bis(3,3′-methylimidazolium)alkyl dibromide, on pure inorganic halometal clusters. Complexes {[C4(Mim)2](Pb2I6)}n (1) (ω = 4), {[C1(Mim)2] (Ag2I4)}n (2) (ω = 1), {[C3(Mim)2](Ag2I4)}n (3) (ω = 3), and {[C4(Mim)2](Ag2I4)}n (4) (ω = 4) possess 1-D chain architecture with different organic cations trapped in it. Compound {[C3′(Mim)2](CuBr3)} (5) (ω = 3) contains the mononuclear anion (CuBr3)2− and intra-molecular coupled organic cation with the formed seven-membered ring. {[C2(Mim)2S2]2(Cu2I2)}n (6) (ω = 2) presents an infinite 2-D coordination polymer as the first representative polyrotaxane example featuring the biimidazolium thiolate cation ligand. All compounds were further characterized with IR spectra and thermal analysis properties.

Efficient Route for the Synthesis of 3,4‐Cycloalkoxy‐2,5‐diethoxycarbonyl‐thiophenes Obtained with Bulky Alkyl Dibromides Using Trialkylamines as Base—Solvent.

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Efficient route for the synthesis of 3,4-cycloalkoxy-2,5-diethoxycarbonyl-thiophenes obtained with bulky alkyl dibromides using trialkylamines as base–solvent

New reaction conditions were investigated for dialkylizing diethyl 3,4-dihydroxy-2,5-thiophenedicarboxylate with sterically hindered alkyl-dibromides, using as reaction system DMF–trialkylamine or only the trialkylamine as base–solvent. This methodology produced the corresponding 3,4-cycloalkoxy-2,5-diethoxycarbonyl-thiophene derivatives faster and with better yields than those reported previously for K 2CO 3–DMF. Experiments were performed with triethylamine, tripropylamine, and tributylamine. Tributylamine produced the best results in a general reaction with alkyl-bromides. Aromatic amines like N, N-dimethylaniline, N-methyldiphenylamine, and triphenylamine failed to react at all. Reactions using only the tributylamine as base–solvent demonstrated that DMF is not necessary as a solvent to obtain good yields.

Synthesis and structural characterization of chiral dicationic imidazolophanes

Various chiral dicationic benzimidazolophanes were obtained from optically pure ( S)-BINOL, benzimidazole and a suitable aryl alkyl dibromide.

A general integrated process for synthesizing olefin oxides.

Metal oxide solid reactants are shown to react with vicinal alkyl dibromides to selectively form olefin oxides and fully regenerable metal bromides.

Synthesis of novel oligo(primary-tertiary alkyl peroxides) via oligocondensation reactions under phase transfer catalysis conditions

Novel oligoperoxides, products of polycondensation of primary alkyl dibromide with tertiary dihydroperoxides, were obtained. The structure of the oligoperoxides was determined by gel permeation chromatography and nuclear magnetic resonance analyses. Their thermal properties were examined by differential scanning calorimetry, and a mechanism of the thermal decomposition was proposed basing on the gel chromatography–mass spectroscopy analysis of the degradation products. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 15–21, 2004

An attempt at the preparative alkyl dibromide reduction using electrodes coated by a polypyrrole film containing the viologen (4,4′-bipyridinium) system

An attempt at the preparative alkyl dibromide reduction using electrodes coated by a polypyrrole film containing the viologen (4,4′-bipyridinium) system

An efficient method for synthesis of symmetrical diketones via reaction of .alpha.-amino-.alpha.-arylacetonitriles (masked acyl anion equivalents) with alkyl dibromides

An efficient method for synthesis of symmetrical diketones via reaction of .alpha.-amino-.alpha.-arylacetonitriles (masked acyl anion equivalents) with alkyl dibromides

Oxidation of N-alkyl-N'-tosylhydrazines with bromine

Oxidation of N-alkyl-N'-tosylhy”razines with bromine yield alkyl bromides, vicinal alkyl dibromides and traces of alcohols. The main products of primary hydrazines are monobromides whereas secondary hydrazines preferably produce dibromides. The reaction proceeds with evolution of nitrogen and hydrobromic acid and by the formation of intermediate sulfinic ester which may be isolated. Various substrates were examined under different conditions to confirm the validity of the reaction mechanism hypothesized.

The synthesis of diene and of vinyl copolymers containing predetermined quantities of polynuclear hydrocarbon or heterocyclic adducts—V. Copolymers formed from styrene or α-methylstyrene, anthracene and alkyl dihalide

When a tetrahydrofuran solution of styrene or α-methylstyrene (M) and anthracene (A) is reacted with alkali metal, anionic species are produced which can be titrated with alkyl dibromides (RBr 2) to produce copolymers. These copolymers have been analysed structurally by NMR spectroscopy and by a model compound approach. With styrene as monomer, the copolymers have been shown to consist of two types of repeat units [AM nAR] and [AR] linked together in a random manner: at equimolar styrene to anthracene ratios, n ∼ 10 and 75 per cent of the anthracene is linked directly to the alkyl ligand as in the second repeat unit. When α-methylstyrene is used, the repeat units are predominantly [M nR] and [AR] with n ∼ 5. Production of copolymers of α-methylstyrene in particular is more efficient for decane dibromide than for butane dibromide, where formation of bridged anthracene derivatives by a cyclization and regeneration of anthracene competes with the copolymerization. The reasons for the structural differences between the copolymers of the two vinyl monomers are discussed.

The synthesis of diene and of vinyl copolymers containing predetermined quantities of polynuclear hydrocarbon or heterocyclic adducts—VI. Copolymers of butadiene, acenaphthylene or phenanthrene, and a linking agent

Reactions of tetrahydrofuran solutions of butadiene and acenaphthylene with alkali metal produce dianionic species which give quantitative yields of copolymers when subsequently titrated with alkyl dibromides. These polymers, however, crosslink on standing; this has been correlated with the presence of a proportion of 1,5-dihydroacenaphthylene adduct in the product. Similar reactions involving phenanthrene are not quantitative and yield materials containing only a small proportion of the phenanthrene added. The low efficiency has been attributed to the low electron affinity of phenanthrene and to the ability of its dianion to react with alkyl halides by electron transfer rather than metathetically.

Synthesis of copolymers. I. Copolymers of styrene and of α‐methylstyrene

AbstractThe compositions of copolymers formed by reacting styrene or α‐methylstyrene (M) with lithium in tetrahydrofuran in the presence of varying amounts of alkyl dibromides (RX2) have been studied. Regular copolymers of structure are formed at 2:1 monomer to dibromide molar stoichiometry, but they become less regular and richer in monomer as the proportion of dihalide decreases. α‐Methylstyrene copolymers change systematically with reactant ratios and a series of materials can be prepared with different glass transition temperatures which can be related to the copolymer compositions. The fast rate of anionic homopropagation of styrene after consumption of the dihalide prevented pure copolymer from being prepared free of homopolystyrene. However, it is shown that the composition of the styrene copolymers is much more sensitive to the initial reactant ratios than is that of the α‐methylstyrene copolymers.

Synthesis of new macrocycles. Part I. Monomeric and dimeric o-phthalate esters

Condensation of the dipotassium salt of o-phthalic acid with a series of alkyl dibromides of increasing chain length afforded cyclic esters ranging in size from a ten- to a thirty-four-membered ring. Dibromides bearing an uneven number of carbon atoms generally yielded dimeric compounds, while the even numbered dibromides gave monomeric compounds. The dimeric esters are highly crystalline and appear to exist in fixed conformations.