Haem d1: development of a new coupling procedure leading to the synthesis of isobacteriochlorins1

Abstract

A new approach has been developed for construction of the western and eastern lactams, e.g. 2 and 3, needed for synthesis of isobacteriochlorins. It involves acylation of pyrroles with lactonic acids to form ketones. These are then efficiently converted into the desired lactams by a short sequence of reactions. All the steps are high yielding and simple to carry out.