Three-Component, One-Pot Sequential Synthesis of Functionalized Cyclazines: 3H-1,2a¹,3-Triazaacenaphthylenes

Abstract

An efficient tandem route to the synthesis of 3H-1,2a(1),3-triazaacenaphthylene derivatives of the cyclazine family has been developed. Target compounds were obtained in moderate to good yields by a Yb(OTf)(3)/Ag(2)CO(3)-catalyzed, three-component domino reaction. This in turn will set the stage for a wide application of this useful reaction for the synthesis of structurally diverse polyheterocyclic skeletons containing the imidazo[1,2-a]pyridine privileged structure.

Palladium‐Catalyzed Route to Three‐Component, One‐Pot Sequential Synthesis of Functionalized Cyclazines: 2,2a1,4‐Triazacyclopenta[cd]indenes

“…The investigation was initiated with 6‐bromopyridin‐2‐amine, benzaldehyde, and ethyl isocyanoacetate as the model substrates to optimize the reaction conditions, including different catalysts, bases, temperature and various solvents, and the results are summarized in Table 1. The formation of GBB condensation product 4 was catalyzed by Yb(OTf) 3 (catalyst 1) in ethanol in accordance with our previous studies 3a,b,7. Therefore, GBB condensation intermediate ( 4 ) was used directly without purification.…”

Efficient Metal‐Free Synthesis of Various Pyrido[2′,1′:2,3]imidazo‐ [4,5‐b]quinolines

“…The structure of the product was confirmed by a single‐crystal X‐ray study (Figure 1). Interestingly, the product resulting from direct N ‐alkylation on the triple bond was never observed 16. The combined electrophilic activation of the triple bond by the tetrabutylammonium cation and the alkaline fluoride anion appeared to be essential for efficient cyclization because KF or tetrabutylammonium iodide (TBAI) introduced separately gave no reaction (Table 1, entries 2 and 3).…”

NIS‐promoted multicomponent reaction of 2‐aminopyridines with aldehydes and nitromethane for the synthesis of 3‐nitroimidazo[1.2‐a]pyridines

“…This structure has also been found in several commercial drugs, including zolpidem, saripidem, zolimidine, and olprinone . Hence, the syntheses of these compounds have drawn significant attention in the past decade …”