The syntheses and NMR spectra of the twelve isomeric thieno[<i>b</i>]fused naphthyridines

Abstract

Abstract Through the use of Pd(0)‐catalyzed couplings between 2‐(2‐trimethylstannyl‐3‐pyridyl)‐1,3‐dioxolane, 3‐trimethylstannyl‐2‐pyridine carboxaldehyde, 3‐trimethylstannyl‐4‐pyridine carboxaldehyde and 4‐trimethyl‐stannyl‐3‐pyridine carboxaldehyde with t ‐butyl‐ N ‐(3‐bromo‐2‐thienyl)carbamate, t ‐butyl‐ N ‐(2‐bromo‐3‐thienyl)carbamate and t ‐butyl‐ N ‐(4‐bromo‐3‐thienyl)carbamate in N,N ‐dimethylformamide at 100°, using cupric oxide as a coreagent, all twelve isomeric thieno[ b ]naphthyridines have been synthesized in an one‐pot procedure. A detailed study of the 1 H and 13 C nmr spectra of these isomers has been undertaken.