We proceeded to investigate the indirect acylation of NaphPO4 with a combination of acetic acid and a secondary activation agent. Carbodiimides are arguably the most popular reagents for carboxylic acid activation and are frequently used in carboxylic anhydride-and ester-based reaction cycles. Thus, we tested a 1:1 admixture of acetic acid and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) at pH 7.5 and 5.5. (entries 9-12). The presence of pyridine significantly enhanced the acetylation and led to activation yields up to 81% (entry12). The experiments were conducted in a more acidic environment (i.e., pH 5.5; entries 11 and 12), since EDC activation is more effective under these conditions. Other