1. Basic Information

• Chinese Name: 2‑Chlorotrityl Chloride Aminomethyl Polystyrene Resin (2‑CTC‑AM Resin)
• English Name: 2‑Chlorotrityl Chloride AM Resin
• Matrix: 1% / 2% divinylbenzene cross‑linked aminomethyl polystyrene beads (Aminomethyl‑PS, AM resin core)
• Functional moiety: 2‑chlorotrityl chloride linker, covalently anchored to AM core via a stable amide spacer.

Difference from standard 2‑CTC: Standard 2‑CTC is directly grafted onto plain polystyrene beads; 2‑CTC‑AM adopts an extended amide spacer to reduce steric hindrance for difficult peptide sequences.

2. Appearance & Typical Specifications

• Physical State: Off‑white to pale beige insoluble polymer microspheres
• Mesh Size: 100‑200 mesh, 200‑400 mesh
• Active Loading Capacity: 0.4～1.2 mmol/g, popular grades: 0.6‑0.8 mmol/g, 0.8‑1.0 mmol/g
• Swelling Behavior: Excellent swelling in DCM, DMF and NMP (4‑9 mL/g). The extended spacer improves reagent accessibility for sterically hindered peptides.

3. Key Chemical Properties

1. Identical cleavage chemistry to conventional 2‑CTC resin: Fmoc‑amino acid loading with DIEA; mild cleavage with dilute TFA (1‑5% TFA/DCM) to retain acid‑sensitive side‑chain protecting groups (Boc, tBu, Trt). Fully de‑protected peptides can be released under high‑concentration TFA cocktail.
2. An amide spacer extends the reactive trityl site away from the polymer backbone, effectively reducing steric crowding, improving coupling yields for long hydrophobic peptides.
3. The amide bond between AM core and trityl linker is stable under repeated Fmoc deprotection, coupling and washing cycles; only the trityl‑ester bond is acid‑cleavable.
4. Bulky ortho‑chlorotrityl scaffold suppresses diketopiperazine (DKP) side‑reactions and amino acid racemization for C‑terminal Pro / Cys peptides.
5. Moisture‑sensitive active chloride group; anhydrous and acid‑free conditions are required for storage and synthesis.

4. Main Applications

1. Fmoc solid‑phase peptide synthesis for fully protected peptide fragments used in convergent long‑peptide assembly.
2. Difficult hydrophobic long peptides, cyclic peptides, pharmaceutical peptide API development (GLP‑‑1 analogues).
3. Preferred upgraded solid support when standard polystyrene‑based 2‑CTC shows insufficient coupling efficiency.
4. Solid‑phase small‑molecule synthesis, peptidomimetic and combinatorial library construction.

   5. Storage & Handling

   • Storage: Keep tightly sealed, dry and protected from light at 2‑8 °C. Avoid moisture to prevent hydrolysis of active chloride.
   • Amino acid loading: DCM as solvent, DIEA as base.
   • Mild cleavage condition: 1‑3% TFA / TIS in DCM for side‑chain protected peptides; concentrated TFA for global deprotection.
   • Operate in a fume hood. Waste liquid containing TFA must be disposed of in compliance with local hazardous‑waste regulations.

   6. Safety Overview

   The dry resin itself is not classified as high‑hazard substance. Fine resin dust may irritate respiratory tract. Concentrated TFA cleavage reagent is highly corrosive; full personal protective equipment is required.