Syntheses of pemptoporphyrin, isopemptoporphyrin, and protoporphyrin IX dimethyl esters by cyclisation of the corresponding 1-bromo-1,19-dideoxy-19-methyl-biladiene-ac dihydrobromides, with use of the 2-(methoxycarbonylamino)ethyl groups as precursors of the peripheral vinyl substituents, are described.