title: An expeditious iodine-catalyzed synthesis of 3-pyrrole-substituted 2-azetidinones.
abstract: 2-Azetidinones and pyrroles are two highly important classes of molecules in organic and medicinal chemistry. A green and practical method for the synthesis of 3-pyrrole-substituted 2-azetidinones using catalytic amounts of molecular iodine under microwave irradiation has been developed. Following this method, a series of 3-pyrrole- substituted 2-azetidinones have been synthesized with a variety of substituents at N-1 and at C-4. The procedure is equally effective for mono- as well as polyaromatic groups at the N-1 position of the 2-azetidinone ring. The C-4 substituent has no influence either on the yield or the rate of the reaction. Optically pure 3-pyrrole-substituted 2-azetidinones have also been synthesized following this methodology. No deprotection/rearrangement has been identified in this process, even with highly acid sensitive group-containing substrates. A plausible mechanistic pathway has also been suggested based on the evidence obtained from ¹H-NMR spectroscopy. The extreme rapidity with excellent reaction yields is believed to be the result of a synergistic effect of the Lewis acid catalyst (molecular iodine) and microwave irradiation.
authors.affiliation: Department of Chemistry, The University of Texas-Pan American, 1201 West University Drive, Edinburg, TX 78539, USA.
authors.forename: Debasish
authors.initials: D
authors.lastname: Bandyopadhyay
authors.forename: Jessica
authors.initials: J
authors.lastname: Cruz
authors.forename: Ram N
authors.initials: RN
authors.lastname: Yadav
authors.forename: Bimal K Banik
authors.initials: BK
authors.lastname: Banik
mesh_terms: D001384:Azetidines / Q000138:chemical synthesis*; D002384:Catalysis / Q000528:radiation effects; D007455:Iodine / Q000737:chemistry*; D008872:Microwaves
chemical_list: C116379:2-azetidinone; D001384:Azetidines; D007455:Iodine