Acid-catalyzed oligomerization of 2-(hydroxymethyl)pyrroles bearing C6F5, 2,6-Cl2C6H3, CF3 and CO2Et groups at β-positions was examined. The reaction of ethyl pyrrole-3-carboxylates gave a mixture of oligomers and type I isomers of porphyrinogens and hexaphyrinogens were isolated when the other β-substituents were sufficiently bulky, for example, mesityl, 2,6-Cl2C6H3 and C6F5 groups. On the other hand, the pyrroles having other electron-withdrawing groups afforded porphyrinogens as the only isolable products.
研究了在 δ² 位上带有
C6F5、2,6-Cl2C6H3、
CF3 和 CO2Et 基团的 2-(羟甲基)
吡咯在酸催化下的低聚物反应。
吡咯-3-
羧酸乙酯的反应产生了一种低聚物混合物,当其他δ-取代基(如
间苯二酚、2,6-Cl2C6H3 和 基团)足够大时,就能分离出
卟啉原和六
卟啉原的 I 型异构体。另一方面,具有其他取电子基团的
吡咯类化合物只能分离出
卟啉原。