Bromination of 3,5-dihydroxybenzoic acid to 4-Bromo-3,5-dihydroxybenzoic acid(https://www.sigmaaldrich.com/catalog/product/aldrich/d110000?lang=en®ion=NL&gclid=EAIaIQobChMIqvnxn6TF4AIVFojVCh2qjASlEAAYASAAEgLFofD_BwE)
Fluorination of Methyl 3,5-dimethoxybenzoate with SelectFluor: 1-chloromethyl-4-fluoro-1,4-diazobicyclo[2.2.2] octane bis(tetrafluoroborate) to 2-Fluoro-3,5-dimethoxy-benzoic acid methyl Ester
see attachment: page 14 ;[144]
Available at https://pubchem.ncbi.nlm.nih.gov/compound/methyl_2-fluoro-3_5-dimethoxybenzoate#section=Chemical-Vendors
Prepare 2-Fluoro-3,5-diethoxy-benzoic acid ethyl ester from 3.5-diethoxy-benzoic acid ethyl ester using SelectFluor (Ref WO 2015057963 Al). Then selective bromination to get ethyl 4-bromo-3,5-diethoxy-2-fluorobenzoate.