K. Okada, H. Takakura, Keishi Nomura
Apr 15, 2000
Citations
0
Influential Citations
3
Citations
Journal
Tetrahedron Letters
Abstract
Abstract A linear pentapyrrole bearing α-hydroxymeythyl group in the terminal was synthesized by the stepwise coupling of α-free pyrrole with azafulvenium ion 6. When it was treated with a catalytic amount of p-toluensulfonic acid under anaerobic condition, followed by aerial oxidation of the products, a statistical mixture of uroporphyrin I–IV octamethyl esters was obtained. It is proposed that this transformation proceeds through a spiro-pyrrolenine as a key intermediate.