Convenient multi-gram scale synthesis of polybrominated imidazoles building blocks

Bahnous, Mebarek; Mouats, Chabane; Fort, Yves

doi:10.1016/j.tetlet.2006.01.066

Cited by 15 publications

(8 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[16][17][18] In fact all three positions in N-methylimidazole can be halogenated which is not surprising given the fact the calculations suggest that the three possible arenium ions have similar standard free energies. [19][20][21] Finally, a 1 : 1 mixture of the 4-and 5-brominated products has been reported for N-benzylimidazole, which is in line with the predictions. 22,23 Computational methodology…”

Section: Introductionsupporting

confidence: 87%

Fast and Accurate Prediction of the Regioselectivity of Electrophilic Aromatic Substitution Reactions

Jimmy¹,

Jensen²,

Monika³

et al. 2017

Preprint

View full text Add to dashboard Cite

While computational prediction of chemical reactivity is possible it usually requires expert knowledge and there are relatively few computational tools that can be used by a bench chemist to help guide synthesis. The RegioSQM method for predicting the regioselectivity of electrophilic aromatic substitution reactions of heteroaromatic systems is presented in this paper. RegioSQM protonates all aromatic C-H carbon atoms and identifies those with the lowest free energies in chloroform using the PM3 semiempirical method as the most nucleophilic center. These positions are found to correlate qualitatively with the regiochemical outcome in a retrospective analysis of 96% of more than 525 literature examples of electrophilic aromatic halogenation reactions. The method is automated and requires only a SMILES string of the molecule of interest, which can easily be generated using chemical drawing programs such as ChemDraw. The computational cost is 1-10 minutes per molecule depending on size, using relatively modest computational resources and the method is freely available via a web server at regiosqm.org. RegioSQM should therefore be of practical use in the planning of organic synthesis.

show abstract

Section: Introductionsupporting

confidence: 87%

Fast and Accurate Prediction of the Regioselectivity of Electrophilic Aromatic Substitution Reactions

Jimmy¹,

Jensen²,

Monika³

et al. 2017

Preprint

View full text Add to dashboard Cite

show abstract

“…The imidazole core is akey for ahuge variety of important biologically active substances. It has found many applications in metalcarbene catalysts and is most important in ionic liquids (ILs) and magnetic ILs [3][4][5][6][7][8]. Polybrominated imidazole building blocks are useful as starting materials in the synthesis of very dense halogenated ILs [9].…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of 2,4,5-tribromo-1-methyl-1H-imidazole, C₄H₃Br₃N₂

Peppel¹,

Köckerling²

2009

Zeitschrift Für Kristallographie - New Crystal Structures

View full text Add to dashboard Cite

C 4H3Br3N2,t riclinic, P1 (no. 2), a =6.9066(3) Å, b =7.0812(3) Å, c =16.1046(6) Å, α =78.093(2)°, β =82.467(2)°, γ =89.781(2)°,Source of material 1-Methyl-1H-imidazole (24.6 g, 0.3 mol) and sodium acetate trihydrate (100 g, 0.7 mol) were dissolved in 350 ml glacial acetic acid and asolution of bromine (143.6 g, 0.9 mol) in 50 ml of glacial acetic acid was added slowly under cooling. The resulting solution was stirred overnight and then poured onto 500 ml of ice water. The precipitate of 2,4,5-tribromo-1-methyl-1H-imidazole was filtered off and recrystallized from aqueous ethanol. Yield: 50.0 g(52 %), mp. 93°C. DiscussionAlready in the late 19th century Wyss and Wallach reported the correct molecular formula of 2,4,5-tribromo-1-methyl-1H-imidazole and they discussed possible chemical structures [1,2].Until now there has been no X-ray determination of the crystal structure of this compound. The imidazole core is akey for ahuge variety of important biologically active substances. It has found many applications in metalcarbene catalysts and is most important in ionic liquids (ILs) and magnetic ILs [3][4][5][6][7][8]. Polybrominated imidazole building blocks are useful as starting materials in the synthesis of very dense halogenated ILs [9]. The title compound crystallizes with two symmetry independent molecules in the asymmetric unit. The orientation of the molecules gives short hydrogen-bonding contacts between Br atoms and methyl groups of neighbouring units. The figure shows such an intermolecular hydrogen-bonding contact as thermal ellipsoid plot at the 50 %probability level.

show abstract

“…Synthesis of Th 3 -Im: 2, 3, 4-tribromoimidazole.-2,3,4-bromoimidazole was synthesized according to the condition described by Bahnous et al 26 (Figure 1). Powdered KHCO 3 (0.3 mol) was added to a solution of 1H-imidazole (0.1 mol) in DMF.…”

Section: Methodsmentioning

confidence: 99%

Synthesis, Characterization and Electrochemical Polymerization of a Comonomer Bearing Thiophene and Imidazole: The Comparison of Impedance Behavior on Different Surfaces

Dolaş

Sezer

Sarac

2016

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

In this study, a comonomer based on imidazole bearing thiophene at 2, 4 and 5-positions named of 2, 4, 5-trithiophenylimidazole (Th 3 -Im) was synthesized by means of Pd catalyzed Still cross coupling reaction. The product was characterized by using H-NMR and FTIR-ATR. It was electrochemically polymerized at a scan rate of 50 mV/s, applying 10-20 scans on different working electrodes such as Pt wire (radius, 1 mm), Au wire (0,5 mm), single carbon fiber (SCF) and ITO-PET (1-1 cm) from solutions containing 0.1 M Th 3 -Im and 0.1 M tetrabuthylammonium perchlorate (TBAP) in dichloromethane (DCM). The Th 3 -Im was oxidized at 0.84 V on the surface of ITO-PET. Furthermore, the effect of Poly(Th 3 -Im) coating on different working electrodes on impedance were investigated, and the data were collected by using electrochemical impedance spectroscopy (EIS). The double layer capacitance, C DL , value was obtained as highest on SCF surface as 0.67 mF. The morphological investigation of the polymer was carried out by using SEM and AFM. It was clearly observed that granular pieces were cumulated on electrode surface, especially on planar surface. It was found that the capacitance values of obtained coating electrodes are strongly affected by the dependence of the morphology of used electrode surface.Electrically conducting polymers (CPs) have been attracted great deal of interest due to their suitability for numerous applications including photovoltaics (PVs), 1 field effect transistors (FETs), 2 light emitting diodes (LEDs) 3 and electro chromic devices (ECDs). 4 In the case of a monomer such as thiophene and its derivatives, having a high oxidation potential compared to the polymer, the high applied voltage causes some degradation of the polymer. This case was named by "thiophene paradox", 5 by meaning that polythiophene (PTh) films deposited on the electrode from common electrochemical solvent are of low quality and are poorly conducting and exhibit poor mechanical properties. 6-8 This problem can be overcome by extending the conjugation of the monomer by introducing different monomers, resulting in a significant reduction in the oxidation potential. 9 On the other hand the bandgap energy of these polymers is dominant among factors affecting optical and electronic properties. 10 The groups attached to a monomer or Donor-Acceptor (DA) type comonomers are very effective on the bandgap of obtained polymer. The comonomers were synthesized by a suitable method because of that DA type polymers consisting of alternating electron donors and acceptors generally have lower bandgaps and wider bandwidths than either of the corresponding homo-polymers when D and A moieties match appropriately. 11 To proceed through charge transfer complex formation in the donor-acceptor system, imidazole ring was participated into a polymer structure as an acceptor. 12 In literature DAD type benzimidazole (BIm) 13 or 4,4-dinonyl-2,2-bithiazole and 3,4-ethylenedioxythiophene (EDOT) bearing comonomers were synthesized and electrochemically polymerized. 14...

show abstract

Convenient multi-gram scale synthesis of polybrominated imidazoles building blocks

Cited by 15 publications

References 17 publications

Fast and Accurate Prediction of the Regioselectivity of Electrophilic Aromatic Substitution Reactions

Fast and Accurate Prediction of the Regioselectivity of Electrophilic Aromatic Substitution Reactions

Crystal structure of 2,4,5-tribromo-1-methyl-1H-imidazole, C₄H₃Br₃N₂

Synthesis, Characterization and Electrochemical Polymerization of a Comonomer Bearing Thiophene and Imidazole: The Comparison of Impedance Behavior on Different Surfaces

Contact Info

Product

Resources

About

Convenient multi-gram scale synthesis of polybrominated imidazoles building blocks

Cited by 15 publications

References 17 publications

Fast and Accurate Prediction of the Regioselectivity of Electrophilic Aromatic Substitution Reactions

Fast and Accurate Prediction of the Regioselectivity of Electrophilic Aromatic Substitution Reactions

Crystal structure of 2,4,5-tribromo-1-methyl-1H-imidazole, C4H3Br3N2

Synthesis, Characterization and Electrochemical Polymerization of a Comonomer Bearing Thiophene and Imidazole: The Comparison of Impedance Behavior on Different Surfaces

Contact Info

Product

Resources

About

Crystal structure of 2,4,5-tribromo-1-methyl-1H-imidazole, C₄H₃Br₃N₂