Palladium catalyzed carbonylative annulation of the C(sp2)–H bond of N, 1-diaryl-1H-tetrazol-5-amines and N, 4-diaryl-4H-triazol-3-amines to quinazolinones. Issue 44 (1st November 2018)

• Record Type: Journal Article
• Authors: Chandrasekhar, Attoor; Ramkumar, Venkatachalam; Sankararaman, Sethuraman
• Is Part Of: Organic & biomolecular chemistry. Volume 16:Issue 44(2018)
• Page Start: 8629
• Page End: 8638
• Publication Date: 2018-11-01
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/c8ob02516a
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : Pd(ii ) catalyzed direct C–H carbonylative annulation of N, 1-diaryl-1 H -tetrazol-5-amines and N, 4-diaryl-4 H -1, 2, 4-triazol-3-amines gave the corresponding triazole and tetrazole fused quinazolinones in good yields. Abstract : Pd(ii ) catalyzed direct C–H carbonylative annulation of N, 1-diaryl-1 H -tetrazol-5-amines and N, 4-diaryl-4 H -1, 2, 4-triazol-3-amines gave the corresponding triazole and tetrazole fused quinazolinones in good yields. This methodology offers a convenient method for the synthesis of these important heterocyclic scaffolds in a highly atom economical process. On the mechanistic aspect weakly nucleophilic triazole and tetrazole moieties function as both directing as well as intramolecular nucleophiles. The catalytically active C–H activated intermediate dimeric Pd complex was isolated and characterized which on exposure to CO gas gave the corresponding tetrazole fused quinazolinone derivative. On the basis of isolation of the intermediate and observed kinetic isotope effects, a mechanism has been proposed for the C–H activated direct carbonylative annulation reaction.