Bipyrrole diacid

Formed primarily from the condensation of bipyrrole-diacid chloride and p-xylenediamine via two routes, a single step and a stepwise approach, with the latter resulting in a higher yield, 4% verses 2% for the former. 

A more direct, 2 + 2 approach to the synthesis of cobalt(III) corroles has been described. It involves condensing a diformyl bipyrrole such as 2.140 with a diacid dipyrrylmethane such as 2.36. This approach is thus similar to the one used to obtain the bifuran-containing corroles 2.3 2.40 described earlier. In the present instance, the diacid bipyrrole 2,141 may also be reacted with a diformyl dipyrrylmethane such as 2.142. This affords corrole 2.125b (Scheme 2.1.37). In either case, the reaction must be carried out in the presence of Co(II) and PPhs. This requirement for a presumably coordinating metal cation is in stark contrast to what is seen in the case of the bifuran analog there, no metal is needed to template the reaction. ... 

The synthesis of rubyrin 7.25 involves an acid-catalyzed 4 + 2 MacDonald-type condensation between the diformyl bipyrrole 7.21 and the diacid tetrapyrrane 7.23 (Scheme 7.2.1). After oxidation and purification, a roughly 20% yield of a blue crystalline solid is obtained, which, on the basis of solution-phase spectroscopic and solid-state structural studies vide infra), was assigned the hexapyrrolic structure 7.25. Using a similar procedure, rubyrins 7.26 and 7.27 were also prepared. While the first of these (like 7.25) proved stable, rubyrin 7.27 was found to decompose during chromatographic purification. It was thus characterized only by UV-vis spectroscopy and mass spectrometry. ... 

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