Pre-loaded Fmoc-amino acid Wang resin
Fmoc-amino acids esterified on Wang with lot-documented loading. Skips the racemization-prone first coupling and accelerates campaigns where the C-terminal residue is His, Cys, or otherwise sensitive to manual loading.
Fmoc-AA
pre-attached
0.3–0.8
mmol/g typical
COA
loading / identity
↓
first coupling risk
Custom
AA on request
Why pre-loaded Wang
Esterification of the first amino acid onto Wang can epimerize Cys, His, and some other residues under standard DIC/DIPEA conditions. Vendor pre-loading uses controlled procedures and QC to deliver a defined Fmoc-AA-Wang ready for the second coupling.
Documented loading (mmol/g) flows directly into coupling stoichiometry without a separate loading assay in your lab—reducing resin waste and batch-to-batch variability at the C-terminus.
Typical specifications
Support
Wang polystyrene–DVB
Mesh per COA
First residue
Fmoc-L/D-amino acid
Stated on label
Assayed loading
0.3–0.8 mmol/g typical
Fmoc UV or supplier method
Epimerization
Controlled at load
Request chiral data if critical
Storage
2–8 °C, dry
Protect from moisture
Shelf life
Supplier-stated months
Lot-specific
Figures are indicative industry-typical values. Lot- and project-specific data appear on the quotation and certificate of analysis.
When to order pre-loaded Wang
| Situation | Recommendation |
|---|---|
| C-terminal His or Cys | Pre-loaded Wang strongly preferred |
| High-throughput library | Saves one synthesis day per target |
| C-terminal Pro/Gly | Consider pre-loaded 2-CTC instead for DKP |
| Novel C-terminal AA | Manual load or custom pre-load quote |
Figures are indicative industry-typical values. Lot- and project-specific data appear on the quotation and certificate of analysis.
Indicative start from pre-loaded Wang
- 01
Swell resin in DCM then DMF; drain.
- 02
Run standard Fmoc deprotection (piperidine/DMF) on the pre-attached residue—first synthetic cycle is coupling residue 2.
- 03
Couple Fmoc-AA-2 with HATU/DIPEA or DIC/Oxyma per your SOP.
- 04
Continue Fmoc SPPS; cleave with TFA as for unloaded Wang.
Ordering and use
Specify AA and loading band
Quote lists exact Fmoc-amino acid, D/L form, and target mmol/g range.
Receive COA
Use assayed loading for all coupling equivalents from residue 2 onward.
Align with C-terminal risk
If DKP is the dominant risk (Pro/Gly), evaluate 2-CTC pre-load instead.
Cleave and release acid
Standard Wang TFA protocol delivers C-terminal carboxylic acid.
What you receive
- Pre-loaded Fmoc-AA-Wang with lot number
- COA: amino acid identity, loading, mesh, appearance
- Residual moisture and storage guidance
- Optional: epimerization or chiral assay on request
- Pack size aligned to pilot or scale-up slots
Frequently asked questions
Common C-terminal residues (Ala, Leu, Phe, etc.) are often catalog items; others on custom lead time.
Related
Wang Resin
p-Alkoxybenzyl alcohol linker on polystyrene–DVB. The workhorse support for Fmoc SPPS of peptides with a free C-terminal carboxylic acid, cleaved in concentrated TFA with scavengers.
View detailsPre-loaded 2-CTC
Fmoc-amino acids on 2-chlorotrityl resin with verified loading. Ideal starting point for protected fragments, C-terminal Pro/Gly sequences, and projects that combine mild cleavage with skip-the-first-load convenience.
View detailsPre-loaded Rink Amide AM
C-terminal Fmoc-amino acid loaded on Rink Amide AM support. Start amide-oriented SPPS with qualified loading and avoid first-coupling variability when delivering CONH2 peptides.
View detailsReady to specify this for your program?
Share sequence, scale and documentation needs. We reply with indicative specs and a project-specific quotation.