meso-Tetrakis (2-pyridyl)-porphyrin (2-PyP) was tetra-N-alkylated with three different α- bromoacetamides to generate a series of water-soluble N-alkylpyridinium porphyrins (1-3). The product mixtures showed a marked preference for the formation of the ααββ atropisomer. With α-bromo-Nn-butylacetamide, the corresponding ααββ 2-tetrakis (Nn- butylacetamido)-pyridyl porphyrin (2-TnBuPyP, 3) was obtained in 69% isolated yield in a ...