Facile approach to benzo[d]imidazole-pyrrolo[1,2-a]pyrazine hybrid structures through double cyclodehydration and aromatization and their unique optical properties with blue emission

Abstract

A modular approach to polycyclic N-fused heteroaromatics is described. Acid-catalyzed reactions of various 1-(2-oxo-2-arylethyl)-1H-pyrrole-2-carbaldehydes with several o-phenylenediamines provided facile access to a number of new benzo[d]imidazole-pyrrolo[1,2-a]pyrazine hybrid structures through double cyclodehydration and aromatization. Optical characterization of the synthesized compounds revealed unique emission properties, with deep blue emission in the aggregated and solid states, and a dramatic substituent effect was observed. Fusion of an additional benzene ring into the benzo[4,5]imidazo[1,2-a]pyrrolo[2,1-c]pyrazine scaffold resulted in a remarkable increase in the intensity of blue fluorescence from the solution along with good cell permeability and negligible phototoxicity, indicating the potential for bioimaging applications. ; Fax: +82 2 884 8334; Tel: +82 2 880 2471 † Electronic supplementary information (ESI) available: 1 H and 13 C NMR spectra of synthesized compounds and CIF les for 8c. CCDC 1919367. For ESI and crystallographic data in CIF or other electronic format see

Iodine catalyzed synthesis of imidazo[1,2-a]pyrazine and imidazo[1,2-a]pyridine derivatives and their anticancer activity

“…Considering the significance of fluorescent molecules acting as chemosensors and biosensors. 33–35 The absorption and fluorescence characteristics of all compounds were investigated in media of different polarity. Among the derivatives, 10b , 10i , 12b and 12i exhibited more favorable fluorescence emission spectra compared to the other compounds.…”

Efficient One‐Pot Multicomponent Approach to 3‐Phenylpyrrolo[1,2‐a]Pyrazine and Novel 3‐Phenylpyrazino[1,2‐a]Indole in Aqueous Medium

“…In 2019 Gi Hun Bae and coworkers developed a [4+1+1] annulation approach forming 3‐(hetero)aryl‐4‐acyl‐3,4‐dihydropyrrolo‐[1,2‐ a ]pyrazines [Scheme 1c] [9] the reaction mechanism involves a diastereoselective Mannich reaction, and intramolecular imine formation leading to the formation of C−C and C−N bonds. The same research group in 2020 reported a newer approach for the synthesis of pyrrolo[1,2‐ a ]pyrazine hybrid molecule [Scheme 1d] [10] by the utilization of o ‐phenylenediamine as an alternative amine source. The mechanism encompasses dehydrative condensation of o‐ phenylenediamine with N‐alkylated pyrrole‐2‐carboxaldehyde intermediate to form a dihydro intermediate which subsequently reacts with an additional carbonyl group, further oxidation leading to the formation of a tetracyclic compound.…”

Efficient, Concise, and Chemoselective Synthesis of 1H‐Benzo[f]indole‐4,9‐dione with 4‐Hydroxycoumarin Substituent via a One‐Pot Three‐Component Reaction

“…These compounds also play significant roles in the pharmaceutical industry due to their structural diversity and biological features [3a,5a,8] . Pyrroles exist in the structure of pharmacologically active compounds, including anti‐inflammatory, antifungal, inhibitors, anti‐microbial, antivirus, insecticidal, and antitumor agents [3a,8b,9] . As a class of prominent fused derivatives of pyrroles, indoles have become an essential structural component of diverse medicinal compounds.…”