1. Synthesis of Spiro[chromene-imidazo[1,2-a]pyridin]-3′-imines via 6-exo-dig Cyclization Reaction
- Author
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Saber Mirzaei, Hormoz Khosravi, Kamran Amiri, Dmitry Dar'in, Hamid Reza Bijanzadeh, Saeed Balalaie, Frank Rominger, Behrouz Nayebzadeh, and Mikhail Krasavin
- Subjects
chemistry.chemical_classification ,chemistry.chemical_compound ,Reaction mechanism ,Nucleophile ,chemistry ,Allene ,Organic Chemistry ,Imine ,Moiety ,Imidazole ,Alkyne ,Medicinal chemistry ,Isomerization - Abstract
A transition-metal-free postmodification of the Groebke-Blackburn-Bienayme (GBB) reaction for the synthesis of spiro[chromene-imidazo[1,2-a]pyridin]-3'-imine was discovered. The unusual transformation represents the first example of activation and the reaction of the imidazole carbon atom. In this postcondensational modification, KOt-Bu acts as a base, which, after the isomerization of an alkyne moiety to allene, causes the next unique nucleophilic reaction of the imidazole carbon atom that results in spirocyclic structures. The proposed reaction mechanism was confirmed based on the DFT calculations.
- Published
- 2021