How is Ethyl 4-[(6-carbamimidamidohexanoyl)oxy]benzoate methanesulfonate (CAS: 56974-61-9) typically synthesized?

Ethyl 4-[(6-carbamimidamidohexanoyl)oxy]benzoate methanesulfonate (CAS: 56974-61-9) is typically synthesized via a multi-step reaction involving the condensation of 4-hydroxybenzoic acid with 6-carbamimidohexanoic acid, followed by esterification and methanesulfonation. The synthesis involves the use of a catalyst and requires careful temperature control to ensure high yield and selectivity. The product is then purified by recrystallization or chromatography methods.