Synthesis
General procedure for the synthesis of 6-bromobenzo[d]isoxazol-3(2H)-ones from 4-bromo-N,2-dihydroxybenzenecarboxamides: (12) A solution of Γ-alkynyl diimidazole (2.0 eq.) in THF (0.1 M) was slowly added dropwise to a solution of 4-bromo-2-hydroxybenzoic acid (1.0 eq.) in THF (0.15 M). The reaction mixture was stirred under reflux conditions for 2 hours. Upon completion of the reaction, THF was removed by rotary evaporator under reduced pressure and the residue was suspended in water. H2O2 (2 equiv.) was added slowly and dropwise at room temperature. The precipitate formed in the reaction mixture was collected by filtration, washed with deionized water and dried overnight in a vacuum drying oven to afford 6-bromobenzo[d]isoxazol-3(2H)-one in 95% yield.
References
[1] Patent: WO2016/115282, 2016, A1. Location in patent: Page/Page column 76; 77
[2] Tetrahedron Letters, 2016, vol. 57, # 48, p. 5301 - 5303
[3] Patent: WO2004/10995, 2004, A1. Location in patent: Page/Page column 37
