Fused-ring systems containing heterocycles are attractive templates for drug discovery. Biologically active 6-5-5+6 fused-ring systems that possess heterocycles are available, but these require a relatively large number of synthetic steps for preparation. Therefore, pyrazolofuropyrazine was designed as a 6-5-5+6 ring system template that incorporates ready accessibility for drug discovery. Pyrazolofuropyrazines were successfully constructed in only a few steps via one-pot SNAr reaction/intramolecular C–H direct arylation. As a drug candidate, pyrazolofuropyrazine has earned a favorable LogP, although significant biological activity has yet to be established; the ready accessibility of pyrazolofuropyrazine template, however, offers an opportunity for the rapid development of promising new drug candidates.
One-pot three-component synthesis of quinoxaline and phenazine ring systems using Fischer carbene complexes