Stepwise synthesis of 2, 6-difunctionalized ethyl pyrazolo[1, 5-a]pyrimidine-3-carboxylate via site-selective cross-coupling reactions: experimental and computational studies. Issue 48 (23rd November 2022)

• Record Type: Journal Article
• Authors: Messaoudi, Chaima; Jismy, Badr; Jacquemin, Johan; Allouchi, Hassan; M'Rabet, Hédi; Abarbri, Mohamed
• Is Part Of: Organic & biomolecular chemistry. Volume 20:Issue 48(2022)
• Page Start: 9684
• Page End: 9697
• Publication Date: 2022-11-23
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/d2ob01760a
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : A variety of novel disubstituted 2-(alknyl, aryl and arylamine)-6-alkynylpyrazolo[1, 5- a ]pyrimidine derivatives was prepared via sequential site-selective cross-coupling reactions from 2, 6-dibromopyrazolo[1, 5- a ]pyrimidine 3 . Abstract : A variety of novel disubstituted 2-(alknyl, aryl and arylamine)-6-alkynylpyrazolo[1, 5- a ]pyrimidine derivatives was prepared via sequential site-selective cross-coupling reactions from 2, 6-dibromopyrazolo[1, 5- a ]pyrimidine 3 . The regio-controlled Sonogashira-type coupling of 3 with a wide range of terminal alkynes proceeded smoothly with excellent selectivity in favor of the C6-position through careful adjustment of the coupling conditions, followed by the subsequent introduction of alkynyl, aryl or arylamine groups at the C2-position via the Sonogashira, Suzuki–Miyaura and Buchwald–Hartwig coupling reactions, respectively. These promising results allow for further use and diversification of the chemically and biologically interesting pyrazolo[1, 5- a ]pyrimidine scaffold. In addition, computational studies were conducted to provide explanations for the origin of regioselectivity.