Reaction of 4-methylphenol (I) with NaH in DMF and 3-fluorobenzaldehyde (II) yields aldehyde (III), which will be converted into secondary amine (V) via a reductive amination with amine (IV) in presence of NaBH3CN in MeOH and catalytic HOAc. Amine (V) couples with dianhydride (VI) in THF in presence of NMM or alternatively in toluene and Et3N. Final treatment with Na2CO3 in THF yields the desired product.