1996 年 44 巻 1 号 p. 48-54
The Friedel-Crafts acylation of ethyl pyrrole-2-carboxylate (3) was studied under several conditions using various Lewis acids and acyl chlorides. The acylation with various acyl chlorides in the presence of aluminum chloride gave exclusively ethyl 4-acylpyrrole-2-carboxylate (5), whereas weaker Lewis acids such as zinc chloride and boron trifluoride etherate gave a mixture of ethyl 4- and 5-acylpyrrole-2-carboxylates.