CuCl-photocatalyzed C-H amination of benzoxazoles

The direct coupling of benzoxazoles and amines was realized by visible light irradiation and CuCl catalysis. Various aminated benzoxazoles were successfully synthesized under mild conditions with air as an oxidant.

Iodine-Mediated Facile One-Pot Access to N-Aryl-2-benzoxazolamines

Facile, iodine-mediated access to N-aryl-2-benzoxazolamines has been achieved in a one-pot manner under mild reaction conditions. Reaction of 2-aminophenols and aryl isothiocyanates afforded N-aryl-2-benzoxazolamines in the presence of molecular iodine and pyridine in tetrahydrofuran at room temperature in moderate to excellent yields.

Methods to Access 2-aminobenzimidazoles of Medicinal Importance

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Benzimidazole (BI) and derivatives are interesting because several of these compounds have been found to have a diversity of biological activities with clinical applications. In view of their importance, the synthesis of BI and its derivatives is still considered as a challenge for synthetic chemists. Examples of compounds used in medicinal chemistry containing BI, as important nucleus, are Astemizole (antihistaminic), Omeprazole (antiulcerative) and Rabendazole (fungicide), some of these compounds have the 2- aminobenzimidazole (2ABI) as base nucleus. The structure of 2ABI derivatives contains a cyclic guanidine moiety, which is interesting because of its free lone pairs, labile hydrogen atoms and planar delocalized structure. The delocalized 10-π electron system and the extension of the electron conjugation with the exocyclic amino group, in 2ABI, making these heterocycles to have amphoteric character. The 2ABI has been used as building blocks for the synthesis of several BI derivatives as medicinally important molecules. On these bases, herein, we present a bibliographic review concerning the recent methodologies used in the synthesis of 2ABIs, including the substituted ones.

The Synthesis of 2-Aminobenzoxazoles Using Reusable Ionic Liquid as a Green Catalyst under Mild Conditions

A facile, green, and efficient method for the direct oxidative amination of benzoxazoles using heterocyclic ionic liquid as catalyst has been developed. The reaction proceeded smoothly at room temperature and gave the desirable 2-aminobenzoxazoles with good to excellent yields (up to 97%). The catalyst 1-butylpyridinium iodide can be easily recycled and reused with similar efficacies for at least four cycles.

A new NBS/oxone promoted one pot cascade synthesis of 2-aminobenzimidazoles/2-aminobenzoxazoles: a facile approach

A rapid and transition metal free synthesis of 2-aminobenzazoles using readily available substrates.

Recent Trends in Copper-Catalyzed C-H Amination Routes to Biologically Important Nitrogen Scaffolds

Nitrogen-containing heterocycles have found remarkable applications in natural product research, material sciences, and pharmaceuticals. Although the synthesis of this interesting class of compounds attracted the interest of generations of organic chemists, simple and straightforward assembly methods based on transition-metal catalysis have regularly been elusive. The recent advancements in the development of C-H functionalization have helped in accomplishing the synthesis of a variety of complex heterocycles from simple precursors. This Focus Review summarizes the recent advances in one particular field: the copper-catalyzed C-N bond formation reactions via C-H bond functionalization to furnish a comprehensive range of nitrogen heterocycles. Applicability and synthetic feasibility of a particular reaction represent major requirements for the inclusion in this review.

Copper-catalyzed electrophilic amination of heteroarenes and arenes by C-H zincation

Direct amination of heteroarenes and arenes has been achieved in a one-pot CH zincation/copper-catalyzed electrophilic amination procedure. This amination method provides an efficient and rapid approach to access a diverse range of heteroaromatic and aromatic amines including those previously inaccessible using CH amination methods. The mild reaction conditions and good functional-group compatibility demonstrate its great potential for the synthesis of important and complex amines.

Direct C–H amination and C–H chloroamination of 7-deazapurines

Selective methods for Pd and Cu-catalyzed C–H aminations and chloroaminations of 7-deazapurines were developed.