title: Synthesis of Pyrroloquinones via a CAN Mediated Oxidative Free Radical Reaction of 1,3-Dicarbonyl Compounds with Aminoquinones.
abstract: Pyrroloquinone ring systems are important structural units present in many biologically active molecules including a number of marine alkaloids. For example, they are found in a series of marine metabolites, such as tsitsikammamines, zyzzyanones, wakayin, and terreusinone. Several of these alkaloids have exhibited antimicrobial, antimalarial, antifungal, antitumor, and photoprotecting activities. Synthesis of pyrroloquinone unit is the key step in the synthesis of many of these important organic molecules. Here, we present a ceric (IV) ammonium nitrate (CAN) mediated oxidative free radical cyclization reaction of 1,3-dicarbonyl compounds with aminoquinones as a facile methodology for making various substituted pyrroloquinones. 1,3-dicarbonyl compounds used in this study are ethyl acetoacetate, acetylacetone, benzoyl acetone, andN,N-dimethyl acetoacetamide. The aminoquinones used in this study are 2-(benzylamino)naphthalene-1,4-dione and 6-(benzylamino)-1-tosyl-1H-indole-4,7-dione. The yields of the synthesized pyrroloquinones ranged from 23-91%.
authors.affiliation: Department of Chemistry, University of Alabama at Birmingham, 901 14th Street South, Birmingham, AL 35294-1240, USA.
authors.forename: Thao
authors.initials: T
authors.lastname: Nguyen
authors.affiliation: Department of Chemistry, University of Alabama at Birmingham, 901 14th Street South, Birmingham, AL 35294-1240, USA.
authors.forename: Dwayaja
authors.initials: D
authors.lastname: Nadkarni
authors.affiliation: Department of Chemistry, University of Alabama at Birmingham, 901 14th Street South, Birmingham, AL 35294-1240, USA ; Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, 901 14th Street South, Birmingham, AL 35294-1240, USA.
authors.forename: Shilpa
authors.initials: S
authors.lastname: Dutta
authors.affiliation: Department of Chemistry, University of Alabama at Birmingham, 901 14th Street South, Birmingham, AL 35294-1240, USA.
authors.forename: Su
authors.initials: S
authors.lastname: Xu
authors.affiliation: Department of Chemistry, University of Alabama at Birmingham, 901 14th Street South, Birmingham, AL 35294-1240, USA.
authors.forename: Sanghun
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Chemistry, University of Alabama at Birmingham, 901 14th Street South, Birmingham, AL 35294-1240, USA.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Murugesan
authors.affiliation: Department of Chemistry, University of Alabama at Birmingham, 901 14th Street South, Birmingham, AL 35294-1240, USA ; Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, 901 14th Street South, Birmingham, AL 35294-1240, USA ; Comprehensive Cancer Center, University of Alabama at Birmingham, 901 14th Street South, Birmingham, AL 35294-1240, USA.
authors.forename: Sadanandan
authors.initials: S
authors.lastname: Velu