Used in peptide synthesis as a protected dipeptide building block, specifically N-Boc-O-tBu-L-threonyl-L-proline, enabling selective coupling reactions without interference from the reactive hydroxyl side group of threonine. The tert-butoxycarbonyl (Boc) protects the N-terminus, and the tert-butyl (tBu) protects the threonine hydroxyl, providing stability under various reaction conditions. Valuable in both solid-phase and solution-phase synthesis of complex peptides. Commonly applied in pharmaceutical and biochemical research for developing bioactive peptides with enhanced metabolic stability, specificity, and purity.