N-Boc-L-4-tert-butylphenylalanine, with CAS number 143415-62-7, is a protected amino acid derivative. Its chemical structure consists of the natural amino acid L-phenylalanine modified with a tert-butyl group at the para position of the phenyl ring and a tert-butoxycarbonyl (Boc) group protecting the amine functionality. This compound is a white to off-white crystalline powder. This Boc-protected, non-natural amino acid serves as a crucial building block (synthetic intermediate) in peptide and medicinal chemistry. The Boc group is a standard, acid-labile protecting group for amines, allowing for orthogonal deprotection strategies during solid-phase peptide synthesis (SPPS) or solution-phase synthesis. The tert-butyl substituent on the phenyl ring introduces steric bulk and lipophilicity, which can be used to modulate the properties of the final peptide or drug candidate, potentially influencing its binding affinity, metabolic stability, and membrane permeability. It is primarily used in research and development for the synthesis of novel peptides, peptidomimetics, and small molecule pharmaceuticals. As a specialty amino acid derivative, it is not a commodity chemical but a high-value intermediate for constructing complex target molecules in drug discovery programs.