Wittig condensation products from nickel meso-formyl-octaethyl-porphyrin and -aetioporphyrin I and some cyclisation reactions

Abstract

Various Wittig condensation products from the named meso-formylporphyrins are described, together with some transformations of the products. Vilsmeier formylation of the nickel meso-vinyl derivatives causes substitution mainly in the side-chain, and acid cyclisation of the meso-acrylaldehyde products results in the formation of a fused benzene ring and the structure of the product is fully defined by X-ray crystallography. In the absence of nickel, mild acid cyclisations of the meso-acrylaldehydes or esters yield purpurins.