Unusual sensitivity to the concentration of ethanol in the boron trifluoride/ethanol-catalyzed synthesis of 5,10,15,20-tetrakis-(4-cyano-2,6-dimethylphenyl)porphyrin by the lindsey method

✍ Scribed by Beat Steiger; Fred C. Anson

• Publisher: Journal of Heterocyclic Chemistry
• Year: 1997
• Tongue: English
• Weight: 310 KB
• Volume: 34
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570340140

✦ Synopsis

Abstract

The boron trifluoride/ethanol‐catalyzed condensation of 4‐cyano‐2,6‐dtmethylbenzaldehyde 1b with pyrrole by the Lindsey method to give the new, ortho‐disubstituted 5,10,15,20‐tetrakis(4‐cyano‐2,6‐dimethylphenyl)porphyrin 2 was found to be highly sensitive to the concentration of ethanol. In the absence of ethanol the yield of porphyrin is only 1%. Yields can be increased to 20–25% with ethanol concentrations of 0.05–0.1% (v/v) but they decrease rapidly at higher concentrations of ethanol. Optimized procedures for the preparation of both 1b and 2 are described and the newly synthesized molecules are characterized by nmr (^1^H and ^13^C), mass spectra and elemental analysis.