Organic Catalytic Multicomponent One-Pot Synthesis of Highly Substituted Pyrroles

Abstract

A multicomponent synthesis of highly substituted pyrroles catalyzed by thiazolium salts has been disclosed. The reaction employs an acyl anion conjugate addition reaction of aldegyde and unsaturated ketones to generate 1,4-dicarbonyl compounds in situ. The subsequent addition of various amines promotes a Paal–Knorr reaction, affording the desired pyrrole nucleus in an efficient one-pot process.

Keywords:

• Highly substituted pyrroles
• Paal–Knorr reaction
• thiazolium salts catalysts

ACKNOWLEDGMENTS

This research was supported by the National Natural Science Foundation of China (20572091; 20576111) and the Cultivation and Construction Fund for the State Key Subject of Physical Chemistry.

Notes

^a Reaction conditions: 25 mol% of A or B and 30 mol% of DBU and 10 mL methanol, reflux for 1–3 h. Amine and the acid were then added. The mixture was refluxed for an additional 1–3 h.

^b Isolated yield after purification.

^a Reaction conditions: 25 mol% of A or B and 30 mol% of DBU, 10 mL methanol, reflux for 1–8 h. Amine/NH₄OAc and HOAc were then added into the solution. The mixture was refluxed for an additional 1–3 h.

^b Isolated yield after purification.