Synthesis of condensed quinoxalines

A novel efficient synthesis of fluorescent, fused quinoxalines was achieved. 6‐Triazolylthiazolo[4,5‐ b ]quinoxalines were synthesized by the diazotisation of 6‐amino‐2‐methylthiazolo[4,5‐ b ]quinoxaline and coupling with selected aromatic amines followed by air oxidation. Diazotised aryl amines were coupled with 6‐amino‐2‐methylthiazolo[4,5‐ d ]quinoxaline followed by subsequent air oxidation afforded 1,2,3‐triazolo[5,4‐ f ]quinoxalino[2,3‐ d ]thiazoles. 6‐Amino‐2‐methylthiazolo[4,5‐ b ]quinoxaline was condensed with conjugated enol ethers followed by cyclization in dowtherm resulted in thiazolo[4,5‐ b ]quinoxalino[6,5‐ b ]pyridine.