Ac-L-Ile-OH contains an N-acetylated, free carboxylic acid form of the amino acid derivative L-isoleucine, featuring the branched aliphatic side chain characteristic of Ile. The molecule bears an acetylated amino group (amide) and an unprotected carboxyl group, with the L stereochemical configuration indicated by the product name. Ac-L-Ile-OH is used as a defined building block and intermediate for peptide-related synthesis and for preparing isoleucine-containing derivatives in solution-phase or solid-phase workflows where an N-acetylated residue is required.
CAT No: CP25735
CAS No:3077-46-1
Synonyms/Alias:N-Acetyl-L-isoleucine;3077-46-1;(2S,3S)-2-acetamido-3-methylpentanoicacid;L-Isoleucine,N-acetyl-;JDTWZSUNGHMMJM-FSPLSTOPSA-N;AC-ILE-OH;Acetylisoleucine;N-acetyl-isoleucine;AmbotzAAA1918;Ac-L-Ile-OH;AC1OENBW;Acetyl-L-alanineanide;N-Acetylisoleucine,L-;UNII-P9CL0Y0BVZ;P9CL0Y0BVZ;AC1Q2C7M;Isoleucine,N-acetyl-,L-;KSC224E1T;SCHEMBL359065;Jsp003168;CHEMBL1221841;CHEBI:21555;CTK1C4219;MolPort-001-794-411;ZINC3123568
Chemical Name:N-alpha-Acetyl-L-isoleucine
Ac-L-Ile-OH is an N-acetylated L-isoleucine derivative supplied as a free carboxylic acid, featuring the isoleucine side chain with a branched hydrophobic character and an acetylated amino terminus that reduces primary amine reactivity. This protected/blocked amino acid form is frequently used as a defined building block or reference material in peptide and protein chemistry workflows where controlling the N-terminus is essential for consistent coupling behavior and analytical reproducibility. Its stable, non-zwitterionic character under many organic conditions also makes it a convenient intermediate for downstream derivatization and method development.
1. Peptide Segment Building Block
Ac-L-Ile-OH is used in peptide synthesis and peptide fragment assembly when an N-acetylated isoleucine residue is required to model an internal residue environment or to cap an N-terminus during fragment condensation strategies. Researchers developing short peptides, protease substrate analogs, or N-terminally modified standards often select this derivative to avoid uncontrolled N-terminus chemistry and to maintain a consistent acetylated end-group across analog series. In custom peptide manufacturing and medicinal chemistry research, the N-acetyl protection pattern supports reproducible coupling outcomes and cleaner downstream purification profiles compared with free amino acids.
2. N-Acetylated Isolated Residue Standards
Ac-L-Ile-OH serves as a defined chemical standard for analytical method development and characterization of N-acetylated amino acid motifs in peptide and protein studies. Analytical chemists and proteomics method developers use N-acetylated amino acid derivatives to validate LC-MS workflows, optimize chromatographic separation, and confirm mass spectral assignments for acetylated fragments or partial hydrolysis products. Because the amino terminus is already acetyl-blocked, it provides a reliable reference for distinguishing acetylated species from free amino acids and for monitoring derivatization or digestion workflows that generate N-acetyl-containing analytes.
3. Pharmaceutical Intermediate Derivatization
Ac-L-Ile-OH is also applied as a practical intermediate in pharmaceutical intermediate development and specialty chemical synthesis where a hydrophobic, chiral amino acid scaffold with a masked primary amine is advantageous. Process and R&D teams commonly incorporate N-acetylated amino acids into downstream building sequences that require selective functional group handling, since the acetylated nitrogen is less prone to side reactions than an unprotected amino group. The free carboxylic acid functionality enables further activation or conversion to coupling-ready derivatives, supporting the preparation of more complex chiral intermediates used in medicinal chemistry and industrial fine chemical manufacturing.
4. Chemical Biology Substrate Analogues
Ac-L-Ile-OH is used to prepare chemically defined substrate analogues and internal-residue mimics for chemical biology experiments focused on N-terminal processing states and amino acid motif recognition in vitro. Researchers studying enzyme specificity, protease activity in controlled biochemical assays, or reaction selectivity in peptide-like systems often rely on N-acetylated amino acid derivatives to reproduce the same N-terminal chemical context across experimental conditions. The acetylated amino terminus helps ensure that observed reactivity or product distributions reflect the intended N-acetylated state rather than variability introduced by free amine chemistry.
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