1. Basic Information

• Chinese Name: 2‑Chlorotrityl Chloride Resin (2‑CTC Resin)
• English Name: 2‑Chlorotrityl Chloride Resin, 2‑CTC Resin
• CAS No.: 42074‑68‑0
• Solid Support: Polystyrene beads cross‑linked with 1% or 2% divinylbenzene (DVB)
• Functional Group: 2‑chlorotrityl chloride, leaving group: chloride ion (Cl⁻)

2. Appearance & Typical Specifications

• Physical State: Off‑white to pale yellow insoluble resin microspheres
• Mesh Size: Common grades: 100‑200 mesh, 200‑400 mesh
• Loading Capacity: Commercial range 0.4～1.6 mmol/g, popular grades: 0.8‑1.2 mmol/g, 1.0‑1.5 mmol/g
• Swelling Behavior: Good swelling in DCM, DMF and NMP (3‑9 mL/g), compatible with standard Fmoc‑SPPS solvent systems

3. Key Chemical Properties

1. Forms an acid‑labile ester linkage with the carboxyl group of the first Fmoc‑protected amino acid in the presence of weak base (DIEA).
2. Extremely acid‑sensitive linker: Cleavage can be achieved with dilute TFA (1‑5% TFA in DCM), preserving acid‑sensitive side‑chain protecting groups such as Boc, tBu and Trt. Fully de‑protected peptides with free C‑terminal carboxylic acid can be released under high‑concentration TFA conditions.
3. Steric hindrance from bulky trityl moiety effectively suppresses diketopiperazine (DKP) formation and amino acid racemization, especially for Pro‑ or Cys‑terminal sequences.
4. Stable under Fmoc deprotection (piperidine) and peptide coupling conditions. The resin is sensitive to trace acid and moisture; anhydrous and acid‑free conditions are required throughout synthesis to avoid premature cleavage.

4. Main Applications

1. Fmoc‑based solid‑phase peptide synthesis (SPPS) for peptides with free C‑terminal carboxylic acid.
2. Synthesis of fully protected peptide fragments for convergent long‑peptide assembly.
3. R&D of pharmaceutical peptide APIs (GLP‑1 agonists, antiviral peptides, cyclic peptides).
4. Solid‑phase synthesis of small molecules, peptidomimetics and combinatorial chemical libraries.

5. Storage & Handling

• Storage: Keep tightly sealed, dry and protected from light at 2‑8 °C. Moisture will hydrolyze active chloride and reduce loading capacity.
• Amino acid loading: DCM as solvent with DIEA as base.
• Mild cleavage recipe: 1‑3% TFA / TIS in DCM; full deprotection uses concentrated TFA cocktail.
• Handle in a fume hood; avoid inhalation of fine resin dust. Waste liquid containing TFA must be disposed of in compliance with local environmental regulations.

6. Safety Overview