1, 2-Addition to trifluoromethylated β-enamino diketones: regioselective synthesis of trifluoromethyl-containing azomethine pyrazoles and isoxazoles. Issue 13 (20th March 2020)

• Record Type: Journal Article
• Authors: Pianoski, Karlos Eduardo; Poletto, Julia; Vieira da Silva, Michael Jackson; Ascencio Camargo, Jeniffer Nascimento; Jacomini, Andrey Petita; Gonçalves, Davana Silva; Back, Davi Fernando; Moura, Sidnei; Rosa, Fernanda Andreia
• Is Part Of: Organic & biomolecular chemistry. Volume 18:Issue 13(2020)
• Page Start: 2524
• Page End: 2537
• Publication Date: 2020-03-20
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/d0ob00319k
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : Trifluoromethylated β-enamino diketones undergo type 1, 2-addition leading to regioselective synthesis of trifluoromethylated azoles containing an azomethine group. Abstract : A simple and efficient methodology for highly regioselective synthesis of azomethine pyrazoles and isoxazoles containing a trifluoromethyl group is reported. The cyclocondensation of trifluoromethylated β-enamino diketones (TBED) with phenylhydrazine and hydroxylamine hydrochloride, in the presence of BF3, provided 5-aryl-4-[( tert -butyl)iminomethyl]-3-trifluoromethylazoles by aza-Michael-type 1, 2-addition. The scope of the reaction was expanded by transimination with arylamines in a one-pot method starting from TBED. Thus, 83 novel 4-[(alkyl/aryl)iminomethyl]-3-trifluoromethylazoles were obtained with high regioselectivity and in yields of 51 to 89%.