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Chemical product profile

HONGKUN / PRODUCT DIRECTORY

Fmoc-Tyr(tBu)-OH | CAS 71989-38-3

A protected L-tyrosine building block for Fmoc peptide assembly, pairing an Fmoc-protected amino group with a tert-butyl-protected phenol while retaining a free carboxyl coupling site.

CAS71989-38-3
Molecular formulaC28H29NO5
Molecular weight459.5 g/mol

Product overview

Tyrosine introduces both an amino-acid stereocentre and a phenolic side chain into peptide synthesis. Fmoc-Tyr(tBu)-OH protects these two reactive functions separately: Fmoc covers nitrogen and tert-butyl covers the phenolic oxygen. The carboxyl group remains available for peptide coupling. Material qualification therefore includes protection-pattern identity, L-configuration and partially deprotected related substances.

Chemical identity

Chemical name
Fmoc-Tyr(tBu)-OH
CAS number
71989-38-3
Molecular formula
C28H29NO5
Molecular weight
459.5 g/mol

Application context

Fmoc solid-phase peptide synthesis uses this building block to introduce an L-tyrosine residue while suppressing side-chain reactions during chain assembly. Published examples include Leu-enkephalinamide synthesis. Fmoc and tert-butyl serve different stages of the protection strategy, so the inquiry should name both groups explicitly. A chiral impurity requirement and chromatographic control of deprotected tyrosine derivatives help align the incoming material with the target peptide impurity profile.

Chemistry and synthetic role

The base-labile Fmoc carbamate and acid-labile tert-butyl ether provide differentiated protection; the alpha-carboxyl group is the coupling handle.

Quality review

Verify both protecting groups

Confirm N-Fmoc and phenolic O-tert-butyl substitution, rather than unprotected Tyr or an esterified carboxyl.

Control D-tyrosine content

Agree a stereoselective method because achiral HPLC does not establish the L/D ratio.

Review partially deprotected species

Identify relevant free-phenol or free-amine derivatives and the method used to report them.

Preparing a specification

State Fmoc-L-Tyr(tBu)-OH, HPLC assay, D-isomer criterion, partially deprotected species, water and residual solvents relevant to coupling.

Packaging and storage

Confirm container compatibility, closure and net weight for the selected grade and destination. Follow the actual supplier SDS and batch label for storage and transport.

Documentation

Request the batch COA, SDS and analytical methods covering the agreed purchasing specification. Confirm which supporting chromatograms and application-specific records are available from the selected manufacturer.

Procurement questions

Is tBu attached to the carboxyl group?

No. Here it protects the phenolic oxygen; the carboxyl group is free.

Does ordinary HPLC establish L-purity?

Only a suitably stereoselective method can distinguish the D-enantiomer.

Which peptide process should the RFQ name?

Specify the Fmoc protection strategy and any peptide-specific chiral or deprotection impurity limits.

Technical sources
  1. PubChem CAS identity lookupNCBI / PubChem
  2. Fmoc-Tyr(tBu)-OH 47623Sigma-Aldrich
  3. Amino Acids and Peptide Synthesis ReagentsTCI