Direct Olefination of Fluorinated QuinoxalinesviaCross‐ Dehydrogenative Coupling Reactions: A New Near‐Infrared Probe for Mitochondria

Abstract

A large library of 5,8‐distyrylquinoxaline fluorophores was synthesized in good‐to‐excellent yields via a palladium‐catalyzed oxidative C–H/C–H cross‐coupling of electron‐deficient fluorinated quinoxalines with electron‐rich styrenes. The resulting quinoxaline fluorophores (Qu‐Fluors) exhibited tunable color emissions with the quantum yields of up to 83% and large Stokes shifts of up to 6236 cm−1 in dichloromethane. The bioimaging performance of the Qu‐Fluors was shown to have potential as near‐infrared fluorescent probes for mitochondria.magnified image

Carbon–Carbon Bond Forming Reactions in Diazines via Transition-Metal-Catalyzed C–H Bond Activation

“…with DMF as the solvent at 130 °C for 7 h. Depending on the substitution pattern at position 5 of the initial quinoxaline, symmetrical and unsymmetrical molecules were obtained in excellent yields (Scheme 11). 24 The reaction appears to undergo a Fujiwara-Moritani-type mechanism although no discussion was reported.…”

A Direct Method for Synthesis of Quinoxalines and Quinazolinones Using Epoxides as Alkyl Precursor

“…N-heterocycles are inseparable from our life for use as drug molecules, functional materials and dyes [1][2][3]. Pyrrolo [1,2-a]quinoxalines and quinazolin-4-ones are two essential heterocyclic skeletons with outstanding biological properties for antimalarial, anticancer, anti-HIV, antibacterial, etc [4][5][6][7][8][9][10][11][12][13][14].…”

KI‐Mediated One‐Pot Transition‐Metal‐Rree Synthesis of 4‐Phenylpyrrolo[1,2‐a]quinoxalines

“…Quinoxalines are widely used structural units, the derivatives of which possess a wide range of important biological functions, anticancer, [1] antibacterial [2] and so on. [3][4][5] All these superiorities appeal continual attention of researchers on its intensive studies. As a significant derivative of quinoxalines, pyrrolo-[1,2-a]quinoxaline skeleton is endowed with various pharmacological molecules that displays excellent biological activities.…”

“…[23] The scope of substance was limited to aromatic ring with double leaving groups. In 2013, applying benzimidazoles and o-haloanilines, benzo [4,5]imidazo[1,2-a]quinoxalines were obtained in excellent yields, [25] and the range of derivatives was rather abundant. In 2015, we employed substituted a-amino acids with 2-(1H-pyrrolo-1-yl)benzene halides to acquire the pyrrolo[1,2-a]quinoxalines, [26] this method featured that amino acids are cheap and widespread in nature and greatly broadened the scope of pyrrolo-[1,2-a]quinoxaline derivatives (Scheme 2).…”