2,2 -bipyrrole aldehyde

Details of the synthesis of metacycloprodigiosin (61) have been given cyciododecanone was converted (by a series of reactions) into the formyl derivative (58) and hence into the pyrrole (59), which was condensed with the known methoxy-bipyrrole aldehyde (60). 3-Hydroxy-pyrromethenes and 3-hydroxy-pyrroles can be alkylated on oxygen with trialkyloxonium tetrafluoroborate, whereas other reagents effect alkylation on nitrogen,and these reactions were... 

Another antiaromatic hexapyrrolic macrocycle, [24]hexaphyrin(l. 0.1.0.1.0), rosarin 167 has been prepared by acid-catalyzed condensation of bipyrrole 166 and an aromatic aldehyde (Scheme 69) (1992JA8306). 

In terms of synthesis, the rosarins are most easily prepared via the condensation of three a-free bipyrroles with three equivalents of an aromatic aldehyde. For instance, rosarin 7.36 was prepared in > 70 /o yield via the condensation of bipyrrole 7.31 with benzaldehyde, followed by oxidation with DDQ (Scheme 7.3.1). In a similar way, the rosarins 7.37-7.39 could also be prepared in good yield. The preparation of rosarins thus bears formal analogy to the Rothemund-Adler-type methodology used to prepare meso-substituted porphyrins. " In marked contrast to what is observed under these latter porphyrin-forming conditions, the rosarins are obtained as 24 jt-electron, non-aromatic 4n 7r-electron species. According to the Franck notation, therefore, the rosarins are formally [24]hexaphyrins-(1.0.1.0.1.0). 

With dichlorocarbene, some bipyrroles give addition products (107) which on hydrolysis form the corresponding aldehydes jt seems to be agreed that... 

---