title: Regioselective synthesis of fused imidazo[1,2-a]pyrimidines via intramolecular C-N bond formation/6-endo-dig cycloisomerization.
abstract: An efficient regioselective cascade synthesis of N-fused imidazo heterocycles has been developed. This cascade transformation proceeds via a transition-metal (copper/silver) catalyzed coupling reaction between 2-aminobenzimidazole, aldehydes, and alkynes leading to the formation of propargylamine intermediate, which regioselectively undergoes 6-endo-dig cyclization through intramolecular N-H bond activation interceded C-N bond formation leading to highly functionalized imidazo[1,2-a]pyrimidines in good to excellent yields.
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute , Sector 10, Jankipuram Extension, Lucknow 226031 India.
authors.forename: Atul
authors.initials: A
authors.lastname: Kumar
authors.forename: Mukesh
authors.initials: M
authors.lastname: Kumar
authors.forename: Shivam
authors.initials: S
authors.lastname: Maurya
authors.forename: Ranjana S
authors.initials: RS
authors.lastname: Khanna
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D001562:Benzimidazoles / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D001562:Benzimidazoles; D006571:Heterocyclic Compounds; D011743:Pyrimidines; D028561:Transition Elements