12, 13, 17, 18-Tetraalkyl-21, 22-dioxaporphy-ones 10 (21, 22- have been compared with those of 3, 7, 13, 1?-tetraethyl-2, 8, 12, dioxa-5-oxophlorins) have been synthesized by MacDonald 18-tetramethyl-21H, 23H-porphyrin-5 (22H)-one (12) which has cyclization from Bis (5-formyl-2-furyl) methanone (4) and also been newly synthesized. NMR shifts did not provide ev-3, 3', 4, 4'-tetraalkyl-2, 2'-dipyrrylmethanes 8 in dichloromethane idence for the ...