Used as an intermediate in the synthesis of ceftazidime, a third-generation cephalosporin antibiotic. It plays a key role in the industrial production process by protecting the carboxylic acid group during chemical reactions, allowing selective modification at other sites of the molecule. The t-butyl ester group is later removed under acidic conditions to yield the active pharmaceutical ingredient. This derivative is not used directly as a drug but is essential in ensuring high yield and purity during manufacturing.