Product Overview

Fmoc-Ile-OH (CAS 71989-23-6; catalog AS1011) is N-Fmoc-L-isoleucine, a beta-branched amino acid building block for Fmoc peptide synthesis. Its alpha-amino group is Fmoc-protected and the carboxyl group remains available for coupling. The hydrocarbon side chain requires no additional protecting group in conventional Fmoc-SPPS.

Quality Specifications and Ordering

Purity: Alan Scientific supplies Fmoc-Ile-OH at >99% purity.

Catalog pack sizes: 25 g, 100 g, 500 g, and 1 kg.

Quality documentation: See Product Documents below for lot-specific COA request details. Review the analytical methods and results reported for the supplied batch.

Quotation: Email [email protected] with AS1011, the pack size, total quantity, delivery destination, and required date. Confirm availability and dispatch lead time before ordering.

Identify any required limits or methods for stereochemical composition and allo-isomer content. Molecular mass alone does not distinguish all relevant isomers.

Beta Branching and Coupling Context

Isoleucine has a sec-butyl side chain with branching close to the peptide backbone. Steric effects can become relevant when beta-branched residues occur near one another or when resin-bound chain accessibility is poor. Evaluate reaction completion for the actual sequence rather than assuming that every Ile incorporation requires the same coupling adjustment.

If incomplete coupling persists across neighboring residues, the limiting factor may include peptide aggregation or the resin environment. Simply increasing activation severity does not address every cause and can introduce additional process risks.

Isoleucine, Leucine, and allo-Isoleucine

Ile and Leu have the same elemental composition and molecular mass but different side-chain connectivity. A routine molecular-mass result therefore does not, by itself, establish which of these building blocks has been supplied or incorporated.

Isoleucine also contains two stereocenters. An allo-isoleucine derivative is not equivalent to the specified L-isoleucine structure. Confirm exact identity when purchasing material for stereochemically defined peptide libraries, hydrophobic sequence motifs, or analogue studies. Effects on structure and binding should be evaluated in the finished peptide.

For the isobaric but structurally different leucine building block, compare Fmoc-Leu-OH before finalizing the sequence and procurement list.

Product Documents

A Safety Data Sheet (SDS / MSDS) is available for this product to support laboratory handling, storage and safety assessment.

MSDS_Fmoc-Ile-OH_AS1011

Certificates of Analysis are batch-specific. Please contact us to request a COA, and we will provide it by email.

Frequently Asked Questions

Which identity checks matter when buying Fmoc-Ile-OH rather than Fmoc-Leu-OH?

Match AS1011, CAS 71989-23-6, and the specified L-isoleucine structure. Leucine and isoleucine have the same molecular formula, so molecular mass alone cannot confirm the choice. State any allo-isomer or other stereochemical requirements when requesting the lot documentation.

Is Fmoc-Ile-OH interchangeable with Fmoc-Leu-OH?

No. They are constitutional isomers with different side-chain connectivity, despite having the same molecular mass.

Does every Ile-containing coupling need to be repeated?

No. The appropriate response depends on measured reaction completion, neighboring residues, resin accessibility, and the chosen synthesis conditions.

Research Use Only

For research use only. Not for human or veterinary use.