Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... 2-Aza-3,7,8,12,13,17,18-heptaalkylporphyrins were synthesized by use of improved '3+1' condensation under non-acidic conditions. ... 2-Aza-3,7,8,12,13,17,18-heptaalkyl-porphyrins were synthesized by use of improved '3+1' condensation under non-acidic conditions.