Regioselective Brønsted Acid-Catalyzed Annulation of Cyclopropane Aldehydes with N'-Aryl Anthranil Hydrazides: Domino Construction of Tetrahydropyrrolo[1,2- a]quinazolin-5(1 H)ones

Priyanka Singh; Navpreet Kaur; Prabal Banerjee

doi:10.1021/acs.joc.9b03170

Regioselective Brønsted Acid-Catalyzed Annulation of Cyclopropane Aldehydes with N'-Aryl Anthranil Hydrazides: Domino Construction of Tetrahydropyrrolo[1,2- a]quinazolin-5(1 H)ones

J Org Chem. 2020 Mar 6;85(5):3393-3406. doi: 10.1021/acs.joc.9b03170. Epub 2020 Feb 4.

Authors

Priyanka Singh¹, Navpreet Kaur¹, Prabal Banerjee¹

Affiliation

¹ Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab 140001, India.

PMID: 31958951
DOI: 10.1021/acs.joc.9b03170

Abstract

A highly regioselective synthesis of tetrahydropyrrolo[1,2-a]quinazolin-5(1H)one derivatives was achieved by reacting cyclopropane aldehydes with N'-aryl anthranil hydrazides in the presence of p-toluene sulfonic acid (PTSA). The transformation involves domino imine formation and intramolecular cyclization to form 2-arylcyclopropyl-2,3-dihydroquinolin-4(1H)-one, followed by nucleophilic ring opening of the cyclopropyl ring to form desired tetrahydropyrrolo[1,2-a]quinazolin-5(1H)one in good to excellent yield with complete regioselectivity. This protocol tolerates a great variety of functional groups and thus provides a simple and step-efficient method for pyrroloquinazolinone synthesis.