Syntheses of Amino Group-Substituted N-Confused Porphyrins

Tetraphenyl N-confused porphyrins (NCTPP) bearing amino substituents were synthesized for the purpose of functionalization toward water-soluble and biocompatible molecules. The Pd-catalyzed coupling reaction of 4-ethynylaniline with the 2-bromo NCTPP Ag(III) complex yields Pd(II) and Ag(III) coupling products (4a and 4b), at 39% and 55%, respectively. The identities of these products were confirmed by the differences in the isotope patterns of their molecular ion peaks as well as other spectroscopic data. The Ag(III) coupling product, 4b, was demetallated to form the final product, 5, with a yield of 85%. The meso-tetrakis(4-nitrophenyl) N-confused porphyrin, 6, was synthesized through a methanesulfonic acid catalyzed condensation of pyrrole with the 4-nitrobenzaldehyde with a yield of 6.8%. Reduction of the compound to meso tetrakis(4-aminophenyl) N-confused porphyrin, 7, was achieved with a yield of 90%.