Synthetic approaches toward macrocyclic sulfonyl crown formazans

Coupling of diazonium salts with ethyl sulfonylpyruvates 1–3 or arenesulfonylacetic acids 14,15 afforded good yields of the corresponding 1,5-symmetrically disubstituted-3-sulfonylformazans 4–11. The new sulfonyl macrocyclic crown formazans 25–32 were prepared by coupling of the appropriate bisdiazonium salts 22–24 with compounds 1–3 or 14,15. © 1996 John Wiley & Sons, Inc.