Synthesis of Pyrazolo[1,5- a]pyridinyl, Pyrazolo[1,5- a]quinolinyl, and Pyrazolo[5,1- a]isoquinolinyl Sulfonyl Fluorides via a [3 + 2] Annulation

J Org Chem. 2023 Mar 3;88(5):3266-3276. doi: 10.1021/acs.joc.2c02242. Epub 2023 Feb 16.

Abstract

A [3 + 2] cycloaddition reaction of N-aminopyridines, N-aminoquinolines, and N-aminoisoquinolines with 1-bromoethene-1-sulfonyl fluoride (BESF) was performed to obtain optimum yields of various useful pyrazolo[1,5-a]pyridinyl, pyrazolo[1,5-a]quinolinyl, and pyrazolo[5,1-a]isoquinolinyl sulfonyl fluorides (43-90% yield). The transformation process showed broad substrate specificity, mild reaction conditions, and operational simplicity. Therefore, the reaction has great applicable value in the field of medicinal chemistry and other disciplines.