CYCLOTETRAMERIZATION OF MODIFIED KNORR PYRROLES INTO PORPHYRINS - A REINVESTIGATION

The tetramerization of 3-ethyl-4-methyl-5-(methoxymethyl)pyrrole deriv atives into etioporphyrins is reinvestigated. This study demonstrates that in most cases the starting materials were misidentified and that, under controlled conditions, the pyrrole redistribution reaction can be minimized and high yields of etioporphyrin 1, relative to the other three isomers observed.