Abstract |
A convenient synthesis of 2-arylpyrroles from the catalytic dehydrogenation of 2-aryl-1-pyrrolines in the presence of commercial palladium-supported on alumina (Pd/Al2O3) is described. The reaction scope was tested for aryl substituents with different steric hindrances and electronic natures. The dehydrogenation reaction conditions such as temperature, reflux time and amount of catalyst, revealed to be highly dependent on the 2-aryl substituent group, moderate to high yields and selectivities being obtained in a reaction involving straightforward work-up and purification procedures. In addition, the synthesis of the corresponding 2-aryl-1-pyrroline starting materials, through the cyclisation reaction involving 4-chlorobutyronitrile and aryl Grignard reagents, is also reported. (C) 2015 Elsevier Ltd. All rights reserved. |