Boc-L-isoleucine methyl ester is a protected amino acid ester derived from L-isoleucine, featuring an isoleucine side chain with a branched hydrophobic alkyl group attached to a stereodefined α-carbon. The molecule contains a Boc (tert-butoxycarbonyl) carbamate protecting group on the amino functionality and a methyl ester on the carboxyl group, yielding a neutral, non-zwitterionic derivative suitable for controlled peptide coupling chemistry. In synthesis, this compound is used as a stepwise building block where the Boc group suppresses undesired amine reactivity while the ester form supports ester-stable handling prior to conversion into peptide intermediates for solid-phase or solution-phase workflows.
CAT No: CP01212
CAS No:17901-01-8
Synonyms/Alias:17901-01-8;BOC-ILE-OME;(2S,3S)-Methyl2-((tert-butoxycarbonyl)amino)-3-methylpentanoate;Boc-L-isoleucinemethylester;Boc-lle-OMe;SCHEMBL1486223;CTK6B1500;KLRYBAAAYDFIEQ-IUCAKERBSA-N;MolPort-020-003-803;BOC-L-ISOLEUCINEMETHYLESTER;ZINC2391128;ANW-63305;AKOS016003563;AM81845;AJ-35722;AK-87728;KB-48339;TC-152050;V3869;K-5483;N-(t-butoxycarbonyl)-L-isoleucinemethylester;N-(t-butyloxycarbonyl)-L-isoleucinemethylester;N-(t-butyloxycarbonyl)-L-isoleucinemethylester;N-(tert-Butoxycarbonyl)-L-isoleucinemethylester;N-(tert.-butyloxycarbonyl)-L-isoleucinemethylester
Boc-L-isoleucine methyl ester is a protected L-amino acid derivative in which the amino group is carbamate-protected with Boc, while the carboxyl group is esterified as a methyl ester. This combination provides a stable, non-zwitterionic building block that is commonly handled in peptide synthesis and intermediate preparation, where controlled reactivity of the protected functional groups is advantageous. The isoleucine side chain offers a hydrophobic, branched aliphatic moiety that is frequently used to introduce steric bulk and nonpolar character into peptides and peptide-derived scaffolds.
1. Fmoc-Free Peptide Building Block
Boc-L-isoleucine methyl ester is used by custom peptide synthesis groups and medicinal chemistry teams to assemble isoleucine-containing peptide segments in Boc-based workflows, particularly when a protected amino acid ester is preferred for segment coupling and downstream deprotection planning. The Boc-protected nitrogen supports selective activation of the carboxyl functionality during peptide assembly, while the methyl ester form enables controlled handling of the growing peptide fragment prior to conversion to the corresponding acid or activated derivative in the next step. This format is especially relevant for preparing hydrophobic peptide sequences where the isoleucine side chain contributes conformational and solubility characteristics to the target peptide.
2. Side-Chain Hydrophobic Segment Design
Boc-L-isoleucine methyl ester is frequently selected in peptide library and peptidomimetic development programs to incorporate the branched, hydrophobic isoleucine residue at defined positions. Research groups working on structure-property relationships use this building block to tune local sterics and nonpolar surface area, which can influence folding propensity, aggregation behavior, and overall physicochemical profile of peptide candidates. The protected ester form also fits well into iterative intermediate construction strategies, where the amino acid is introduced as a discrete, well-defined unit before final functional group adjustments to reach the desired peptide termini.
3. Pharmaceutical Intermediate Preparation
Boc-L-isoleucine methyl ester serves as a practical intermediate for the preparation of isoleucine-derived building blocks used in medicinal chemistry and specialty chemical manufacturing. Process development teams often rely on Boc-protected amino acid esters to create downstream coupling partners, such as carboxylic acid derivatives or activated intermediates, while maintaining compatibility with standard organic synthesis conditions. The methyl ester provides convenient physical handling and reactivity control during intermediate transformations, and the Boc group helps preserve the amino functionality until it is intentionally unmasked for subsequent steps in the synthesis of peptide-like fragments and amino acid-containing scaffolds.
4. Analytical Reference Material Synthesis
Boc-L-isoleucine methyl ester is also used in analytical method development contexts where amino acid-derived protected standards or calibration precursors are needed to validate derivatization and chromatographic workflows. Laboratories preparing LC-MS or HPLC-based assays for protected amino acid intermediates often require well-characterized, structurally defined reference substances that reflect the same protection pattern used in their sample preparation. The Boc/methyl ester combination provides a distinct chemical signature that can improve traceability of intermediate handling steps during process monitoring, impurity profiling, and method verification for amino acid derivative assays.
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