Three-Step Continuous Flow Synthesis of the Intermediate 4-Fluoro-2-methoxy-5-nitrophenol of Linzagolix

4-Fluoro-2-methoxy-5-nitrophenol is a key intermediate of the GnRH receptor antagonist Linzagolix. The traditional synthetic methods have several disadvantages including prolonged reaction time and safety issues. Herein, we describe a three-step continuous flow synthesis of 4-fluoro-2-methoxy-5-nitrophenol via esterification, nitration, and hydrolysis. The total residence time was 234 s, and the total yield was 85.6%, which substantially reduced the reaction time and considerably improved the process safety as well as the total yield.