Simple Synthesis of Pyrroles Under Solvent-Free Conditions

Abstract

Paal–Knorr condensation of 2,5-hexadione with primary amines in the presence of a catalytic amount of praseodymium(III) trifluoromethanesulfonate under solvent-free conditions has been accomplished with an excellent yield. This method is a very easy, rapid, and high-yielding reaction for the synthesis of N-substituted pyrrole derivatives.

Keywords:

• Paal–Knorr reaction
• praseodymium tiflate
• pyrroles
• solvent-free conditions

Notes

^a Yields refer to pure products and were characterized by comparison of their mp, IR, and ¹H NMR spectra with those of authentic samples.^[ 9–14 ^]