1: methyl 1-bromo-3-naphthoate With potassium hydroxide in methanol; water/glacial acetic acid (1:1) 19.5 h; 2: 4-bromo-N-hydroxy-2-naphthamide With phosphorus tribromide in o-di-fluorobenzene T=25 - 85°C; 18 h;

phosphorus tribromide in o-di-fluorobenzene T=85°C; 18 h; Inert atmosphere;

1.1: phosphorus tribromide / o-di-fluorobenzene / 18 h / 85 °C / |Inert atmosphere 2.1: hexane; tetrahydrofuran / 0.5 h / -75 °C / |Inert atmosphere 2.2: -75 - -60 °C View Scheme