UNUSUAL SENSITIVITY TO THE CONCENTRATION OF ETHANOL IN THE BORON TRIFLUORIDE ETHANOL-CATALYZED SYNTHESIS OF 5,20-TETRAKIS(4-CYANO-2,6-DIMETHYLPHENYL)PORPHYRIN BY THE LINDSEY METHOD/
B. Steiger et Fc. Anson, UNUSUAL SENSITIVITY TO THE CONCENTRATION OF ETHANOL IN THE BORON TRIFLUORIDE ETHANOL-CATALYZED SYNTHESIS OF 5,20-TETRAKIS(4-CYANO-2,6-DIMETHYLPHENYL)PORPHYRIN BY THE LINDSEY METHOD/, Journal of heterocyclic chemistry, 34(1), 1997, pp. 269-272
The boron trifluoride/ethanol-catalyzed condensation of 4-cyano-2,6-di
methylbenzaldehyde 1b with pyrrole by the Lindsey method to give the n
ew, ortho-disubstituted 5,20-tetrakis(4-cyano-2,6-dimethylphenyl)porph
yrin 2 was found to be highly sensitive to the concentration of ethano
l. 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. Op
timized procedures for the preparation of both 1b and 2 are described
and the newly synthesized molecules are characterized by nmr (H-1 and
C-13) mass spectra and elemental analysis.