Aryl Azides as Forgotten Electrophiles in the Van Leusen Reaction: A Multicomponent Transformation Affording 4-Tosyl-1-arylimidazoles

1,2,3-Benzotriazine Synthesis by Heterocyclization of p-Tosylmethyl Isocyanide Derivatives

An efficient methodology to form 4-alkoxy- and 4-aryloxybenzo[d][1,2,3]triazines via an intramolecular heterocyclization of 1-azido-2-[isocyano(p-tosyl)methyl]benzenes under basic conditions has been developed. DFT calculations have been performed to further understand the mechanism of this heterocyclization, which occurs in good to excellent yields with a broad scope.

An electrochemical tandem Michael addition, azidation and intramolecular cyclization strategy for the synthesis of imidazole derivatives

An electrochemical-oxidation-induced intramolecular annulation used for the synthesis of imidazole was developed under undivided electrolytic conditions. In an undivided cell, amines, alkynes and azides could smoothly participate in the transformation to furnish a variety of substituted imidazoles through the tandem Michael addition/azide/cycloamine reaction. The reaction could be easily handled and avoided the use of both transition metal catalysts and peroxide reagents, which is in line with the concept of green chemistry.

Ion-Pairing Assemblies of Anion-Responsive π-Electronic Systems Bearing Triazole Moieties Introduced by Click Chemistry

In this study, the diverse derivatives of dipyrrolyldiketone boron complexes as anion-responsive π-electronic systems were synthesized via the Huisgen cycloaddition of an ethynyl-substituted anion receptor and azide derivatives. The obtained triazole-substituted anion receptors showed effective anion-binding behaviors and ion-pairing assemblies comprising receptor-anion complexes and countercations. Solid-state ion-pairing structures were modulated according to the introduced azide moieties along with coexisting bulky and π-electronic cations.

Fe(III)-Catalyzed N-Amidomethylation of Secondary and Primary Anilines with TosMIC

A Fe(III)-catalyzed N-amidomethylation of secondary and primary anilines with p-toluenesulfonylmethyl isocyanide (TosMIC) in water is described. TosMIC plays dual roles as the source of methylene as well as an amidating reagent to form α-amino amides in this multicomponent reaction. The combination of TosMIC and other isocyanides was also investigated to give the desired products in acceptable yields. The current protocol features use of iron catalyst and nontoxic media, broad substrate scope, mild conditions, and operational simplicity.

Bis-triazolylchalcogenium-Functionalized Benzothiadiazole Derivatives as Light-up Sensors for DNA and BSA

A range of bis-triazolylchalcogenium-BTD 3 was synthesized by a copper-catalyzed azide-alkyne cycloaddition of azido arylchalcogenides 1 and 4,7-diethynylbenzo[c][1,2,5]thiadiazole 2. Eight new compounds were obtained in moderate to good yields using 1 mol % of copper(II) acetate monohydrate under mild reaction conditions. In addition, the synthesized bis-triazolylchalcogenium-BTD 3a-3h were investigated regarding their photophysical, electrochemical, and biomolecule binding properties in solution. In general, compounds presented strong absorption bands at the 250-450 nm region and cyan to green emission properties. The redox process attributed to the chalcogen atom was observed by electrochemical analysis (CV techniques). In addition, spectroscopic studies by UV-vis, steady-state emission fluorescence, and molecular docking calculations evidenced the ability of each derivative to establish interactions with calf-thymus DNA (CT-DNA) and bovine serum albumin (BSA). The behavior presented for this new class of compounds makes them a promising tool as optical sensors for biomolecules.

Iron-Mediated Selective Sulfonylmethylation of Aniline Derivatives with p-Toluenesulfonylmethyl Isocyanide (TosMIC)

An iron-mediated highly selective C-H sulfonylmethylation of aniline derivatives with p-toluenesulfonylmethyl isocyanide in a mixture solvent of H₂O and PEG₄₀₀ under an Ar atmosphere has been realized. This transformation proceeds with operational convenience, use of earth-abundant metal catalyst and nontoxic media, broad substrate scope, and good functional group tolerance. The current methodology could be applied to the regioselective C-H sulfonylmethylation of indolines, tetrahydroquinolines, and tertiary anilines.

Synthesis of Imidazole-Based Medicinal Molecules Utilizing the van Leusen Imidazole Synthesis

Imidazole and its derivatives are one of the most vital and universal heterocycles in medicinal chemistry. Owing to their special structural features, these compounds exhibit a widespread spectrum of significant pharmacological or biological activities, and are widely researched and applied by pharmaceutical companies for drug discovery. The van Leusen reaction based on tosylmethylisocyanides (TosMICs) is one of the most appropriate strategies to synthetize imidazole-based medicinal molecules, which has been increasingly developed on account of its advantages. In this review, we summarize the recent developments of the chemical synthesis and bioactivity of imidazole-containing medicinal small molecules, utilizing the van Leusen imidazole synthesis from 1977.