Asymmetric Porphyrin Analysis

The Lindsey’s condensation method for asymmetric porphyrin synthesis is presented schematically in Figure 2.4. The methodology involved a condensation reaction between an aldehyde and pyrrole to form porphyrinogen, followed by the oxidation step sequentially. This method also allows for milder conditions, while various types of functional groups and protecting groups such as alkyl groups, alcohol, dioxane, can be introduced into the porphyrin meso position. Lindsey’s method can be considered as the easiest method to produce meso-subtituted porphyrins with yields up to 50% can be achieved depending on the choice of aldehyde and acid (Lindsey, 2009).

Figure 2.4 Lindsey condensation method for asymmetric porphyrin synthesis

The MacDonald type [2+2] condensation method was developed to modify the Lindsey’s method. The synthetic pathway was used to condensate two different dipyrromethanes with one of them possessing the diol functional group as depicted in Figure 2.5. Utilizing this method, the two dipyrromethanes were condensed in organic acid condition (Arsenault et al., 1960).

Figure 2.5 [2+2] Mac-Donald condensation between diol-type dipyrromethane and dipyrromethane

The synthetic metallopophyrin was used also by chemists as biomimetic agents to study complexed biological processes. Besides that, the synthetic metalloporphyrin contributed to the development of protein-free in-vitro catalyst useful in industrial chemical reactions (Wijesekera and Dolphin, 1994). Several methods have been developed for the synthesis of various types of metalloporphyrins with different functional groups and several media were studied to synthesize the metalloporphyrin (Alder et al., 1970; Dong et al., 2007; Zhao,