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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
Author(s) -
Steiger Beat,
Anson Fred C.
Publication year - 1997
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570340140
Subject(s) - chemistry , boron trifluoride , ethanol , porphyrin , yield (engineering) , catalysis , pyrrole , boron , medicinal chemistry , condensation , proton nmr , molecule , organic chemistry , nuclear chemistry , inorganic chemistry , materials science , physics , metallurgy , thermodynamics
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.