From the extensive work on the synthesis of pyrroles, the Paal–Knorr method has received increasing attention from synthetic perspectives. 1 These techniques clearly extend the scope of this objective, but success with less nucleophilic aromatic amines has not been reported. Moreover, microwave irradiation or considerable amounts of acids are always necessary in the Paal–Knorr reaction. 2, 3 and 4 Therefore, mild reaction conditions that can overcome the ...
