Fmoc-D-Arg(Pbf)-OH

Fmoc-D-Arg(Pbf)-OH is the standard protected D‑arginine building block for Fmoc solid‑phase peptide synthesis (Fmoc SPPS), enabling the introduction of D‑arginine residues into synthetic peptides with high coupling efficiency and minimal side reactions. Unlike earlier protecting groups for arginine (e.g., Mtr, Pmc), the Pbf group in Fmoc-D-Arg(Pbf)-OH offers superior acid lability — cleaving rapidly under standard TFA cocktails — and is less prone to side reactions such as sulfonamide formation during chain assembly. The Pbf group in Fmoc-D-Arg(Pbf)-OH also eliminates the risk of lactam formation from the δ‑carboxamide and reduces the likelihood of N‑terminal guanidinium modification during base treatments, making Fmoc-D-Arg(Pbf)-OH the preferred choice for assembling arginine‑rich and long‑chain peptides. Cosperpharm supplies Fmoc-D-Arg(Pbf)-OH as a high‑purity crystalline solid, with each batch fully characterized by HPLC, TLC, optical rotation, and moisture content — documentation that supports both research applications and regulatory filing packages for peptide‑based therapeutics.

Product Parameters

Product Advantages

1. Gold‑Standard Pbf Side‑Chain Protection

The Pbf group in Fmoc-D-Arg(Pbf)-OH represents the current gold standard for arginine protection in Fmoc SPPS. Compared to earlier protecting groups (Mtr, Pmc), Pbf offers faster cleavage under standard TFA cocktails, improved resistance to side reactions (including sulfonamide formation and lactamization), and reduced risk of N‑terminal guanidinium modification during base treatments — features that make Fmoc-D-Arg(Pbf)-OH the preferred choice for assembling long, complex, and arginine‑rich peptide sequences.

2. D‑Configuration for Protease‑Resistant Peptide Therapeutics

The D‑enantiomer configuration of Fmoc-D-Arg(Pbf)-OH enables the synthesis of D‑peptides that resist proteolytic degradation by endogenous proteases — a critical advantage for developing peptide therapeutics with extended in vivo half‑lives. This feature makes Fmoc-D-Arg(Pbf)-OH indispensable for designing protease‑stable D‑peptide antagonists, D‑peptide inhibitors of protein‑protein interactions, and metabolically stable bioactive peptides.

3. Superior Performance in Automated SPPS

Fmoc-D-Arg(Pbf)-OH is fully validated for use in automated Fmoc SPPS with standard activation chemistries (HBTU/HOBt, PyBOP, COMU) and is compatible with both continuous‑flow and batch synthesizers. The Pbf group eliminates the risk of lactam formation from the arginine side chain — a known limitation of earlier protecting groups — ensuring high‑purity crude products even for arginine‑rich sequences.

4. Dual‑Use: Synthetic Building Block and Reference Standard

Cosperpharm supplies Fmoc-D-Arg(Pbf)-OH at multiple quality levels: research grade (≥ 95% HPLC) for peptide synthesis applications; and reference standard grade (≥ 98% with full characterization) for use as an analytical standard in method development, quality control, and abbreviated new drug application (ANDA) filings for peptide therapeutics.

5. Broad Utility Across Peptide Science

From the synthesis of cell‑penetrating peptides (CPPs) containing multiple arginine residues for intracellular delivery applications, to the preparation of D‑peptide antagonists targeting protein‑protein interactions, and the development of antimicrobial D‑peptides with enhanced stability — Fmoc-D-Arg(Pbf)-OH serves as a foundational building block across the full spectrum of peptide science.

Synthetic Route

1. Add H-Arg(Pbf)-OH, 120 L of water, and THF to the reactor, then adjust the pH to 8.5 using Na₂CO₃.

2. Gradually add Fmoc-Osu (fluorene methoxycarbonyl succinimide) while maintaining a temperature of 15–20°C and pH at 8–9 to ensure complete reaction of Arg(Pbf), avoiding excess Fmoc-Osu as much as possible. Monitor the reaction progress using a TLC tracking plate; calculate the Chemicalbook reaction time as 6 hours from the addition of Fmoc-Osu.

3. Purification: Extract with petroleum ether/ethyl acetate (2:1); acidify the aqueous phase with HCl to pH 3 and stir for 2 hours at 0–10°C; extract the product with ethyl acetate; wash with saturated saline solution until pH reaches 6; dry with anhydrous sodium sulfate, remove solids by vacuum filtration, concentrate the filtrate, obtain a solid product by reduced-pressure concentration, and finally dry it under vacuum. The product has a purity of 99.6%, with maximum impurity content of 0.09% and L-isomer content of 0.15%.

Product Quality Assurance

Cosperpharm has established a comprehensive quality assurance system for Fmoc-D-Arg(Pbf)-OH that meets the rigorous expectations of both peptide synthesis raw materials and analytical reference standards. Thorough analytical characterization. Each batch undergoes HPLC purity verification (≥ 95% for research grade; ≥ 98% for reference grade), TLC analysis, enantiomeric purity assessment (≤ 0.5% L‑enantiomer), loss‑on‑drying determination (≤ 3.0%), optical rotation measurement ([α]₂₀/D +4.5 to +6.5°, c = 1, DMF), melting point verification, and appearance verification. Full batch traceability with retention samples. From raw material procurement (D‑arginine and Pbf‑Cl from qualified suppliers) through Pbf protection, Fmoc installation, purification, and final packaging, every step is fully documented and traceable. Each batch receives a unique lot number with sufficient retention samples maintained in accordance with Cosperpharm quality procedures. Stability monitoring program. Cosperpharm conducts ongoing stability studies under recommended storage conditions: long‑term storage at −20 °C under inert atmosphere, with accelerated stability studies conducted on representative batches. Stability summaries are updated regularly, with full data packages available to support customer regulatory submissions. Documentation ready for regulatory submission. Every shipment includes a Certificate of Analysis (COA) with batch‑specific purity and characterization data, a Safety Data Sheet (SDS), and customs documentation for international delivery. For customers preparing ANDA or NDA filings for peptide therapeutics, Cosperpharm can provide DMF‑ready documentation packages, method validation reports, stability data, and custom quality agreements upon request. Customer‑initiated quality audits. Qualified customers are welcome to audit Cosperpharm‘s manufacturing, quality control, and documentation facilities. ISO compliance documentation is available upon request.

Contact Us

Ready to incorporate Fmoc-D-Arg(Pbf)-OH into your peptide synthesis workflow? From research‑scale grams to kilogram quantities for commercial manufacturing, Cosperpharm delivers high‑purity protected amino acids with the documentation depth and supply reliability you need. Connect with our team today to discuss your requirements, request a quote, or schedule a technical consultation. We look forward to supporting your next peptide project.