130611-87-9Relevant academic research and scientific papers
Porphyrins with exocyclic rings. Part 23: Synthesis of porphyrins with large exocyclic rings-cyclohexadeca[b]pyrroles and porphyrins therefrom
Lash, Timothy D.,Marron, Thomas G.,Bastian, Jolie A.
, p. 12343 - 12351 (2007)
Knorr-type condensation of cyclododecanone, cyclopentadecanone, and cyclohexadecanone with phenylhydrazones derived from acetoacetate esters in the presence of zinc dust at elevated temperatures gave the corresponding large ring cycloalka[b]pyrroles in excellent yields. A cyclohexadeca[b]pyrrole was reacted with lead tetraacetate to give an acetate derivative, and this condensed with α-unsubstituted pyrroles in the presence of p-toluenesulfonic acid in acetic acid to give a series of related dipyrrolic structures. Hydrogenolysis of the benzyl ester protective groups, followed by '2+2' condensations with dipyrrylmethane dialdehydes, gave unusual cycloalkanoporphyrins with 16-membered exocyclic rings. When an alkyl group is situated next to the carbocyclic ring, proton NMR spectroscopy indicates that the conformational mobility of the carbocyclic unit is severely restricted.
