Divergent and Regioselective Synthesis of 1,2,4- and 1,2,5-Trisubstituted Imidazoles

Brønsted Acid-Catalyzed Synthesis of 1,2,5-Trisubstituted Imidazoles via a Multicomponent Reaction of Vinyl Azides with Aromatic Aldehydes and Aromatic Amines

A facile and efficient approach to the synthesis of 1,2,5-trisubstituted imidazoles is developed via a multicomponent reaction under metal-free catalysis. Under Brønsted acid catalysis, the desired products can be obtained from readily available vinyl azides, aromatic aldehydes, and aromatic amines without generating any toxic waste. The convenient operations and high functional group compatibility indicate that this approach offers an attractive alternative method for the synthesis of imidazole derivatives.

Total synthesis and cytotoxicity of Leucetta alkaloids

The total synthesis of a number of representative natural products isolated from Leucetta and Clathrina sponges containing a polysubstituted 2-aminoimidazole are described. These syntheses take advantage of the site specific metallation reactions of 4,5-diiodoimidazoles resulting in the syntheses of three different classes of Leucetta derived natural products. The cytotoxicities of these natural products, along with several precursors in MCF7 cells were determined through an MTT growth assay. For comparative purposes a series of naphthimidazole-containing family members are included.

Silver-catalyzed [3 + 2] domino reaction: an efficient strategy to synthesize imidazole-5-carbaldehydes

An unprecedented regioselective silver-catalyzed [3 + 2] domino reaction of amidines and ynals for the formation of C–N bonds has been developed.

C-I...N and C-I...π halogen bonding in the structures of 1-benzyliodoimidazole derivatives

Halogen bonding is a well-established and intensively studied intermolecular interaction that has also been used in the preparation of functional materials. While polyfluoroiodo- and polyfluorobromobenzenes have been widely used as aromatic halogen-bond donors, there have been very few studies of iodoimidazoles with regard to halogen bonding. We describe here the X-ray structures of three iodoimidazole derivatives, namely 1-benzyl-2-iodo-1H-imidazole, C₁₀H₉IN₂, (1), 1-benzyl-4-iodo-1H-imidazole, C₁₀H₉IN₂, (2), and 1-benzyl-2-iodo-1H-benzimidazole, C₁₄H₁₁IN₂, (3), and the halogen bonds that dominate the intermolecular interactions in each of these three structures. The three-dimensional structure of (1) is dominated by a strong C-I...N halogen bond, with an N...I distance of 2.8765 (2) Å, that connects the molecules into one-dimensional zigzag ribbons of molecules. In contrast, the three-dimensional structures of (2) and (3) both feature C-I...π halogen-bonded dimers.

A novel bioelectrochemical interface based on in situ synthesis of gold nanostructures on electrode surfaces and surface activation by Meerwein's salt. A bioelectrochemical sensor for glucose determination

A novel effective bioelectrochemical sensor interface for enzyme biosensors is proposed. The method is based on in situ synthesis of gold nanostructures (5-15 nm) on the thin-film electrode surface using the oleylamine (OA) method, which provides a high-density, stable, electrode interface nanoarchitecture. New method to activate the surface of the OA-stabilized nanostructured electrochemical interface for further functionalization with biomolecules (glucose oxidase enzyme) using Meerwein's salt is proposed. Using this approach a new biosensor for glucose determination with improved analytical characteristics: wide working range of 0.06-18.5mM with a sensitivity of 22.6 ± 0.5 μAmM(-1)cm(-2), limit of detection 0.02 mM, high reproducibility, and long lifetime (60 d, 93%) was developed. The surface morphology of the electrodes was characterized by scanning electron microscopy (SEM). The electrochemical properties of the interface were studied by cyclic voltammetry and electrochemical impedance spectroscopy using a Fe(II/III) redox couple. The studies revealed an increase in the electroactive surface area and a decrease in the charge transfer resistance following surface activation with Meerwein's reagent. A remarkably enhanced stability and reproducibility of the sensor was achieved using in situ synthesis of gold nanostructures on the electrode surface, while surface activation with Meerwein's salt proved indispensable in achieving an efficient bioelectrochemical interface.

Development of a regioselective N-methylation of (benz)imidazoles providing the more sterically hindered isomer

An efficient and highly regioselective N-methylation of (NH)-(benz)imidazoles furnishing the sterically more hindered, less stable, and usually minor regioisomer has been developed. The methodology involves very mild reaction conditions and tolerates a wide range of functional groups.

4,5-Diiodo-2-phenyl-1H-imidazole

The structure of the title compound, C(9)H(6)I(2)N(2), contains two symmetry-independent mol-ecules. The inter-planar angles between the imidazole and phenyl ring planes are 16.35 (3) and 17.48 (6)°. Mol-ecules are connected via N-H⋯N hydrogen bonds to form zigzag chains along the b axis. The title compound is the first example of a structurally characterized 4,5-diiodo-imidazole with an organic substituent in the 2-position and without protection on the N-H group of imidazole.