In the rigorous world of pharmaceutical research and chemical synthesis, precision and accuracy are non-negotiable. For professionals working with peptide synthesis, understanding the detailed chemical specifications of essential building blocks like Fmoc-Glu(OtBu)-Ser(Psi(Me,Me)Pro)-OH is fundamental to experimental success. This article outlines the key technical data and considerations when sourcing this critical intermediate.

Fmoc-Glu(OtBu)-Ser(Psi(Me,Me)Pro)-OH, identified by its CAS Number 909115-33-9, is a dipeptide derivative widely utilized in solid-phase peptide synthesis (SPPS). Its molecular formula is C30H36N2O8, with a molecular weight of approximately 552.62 g/mol. These fundamental parameters are crucial for stoichiometric calculations and reaction monitoring during synthesis. The compound typically presents as a white to off-white powder, indicating the expected physical state for high-purity organic intermediates.

The quality of Fmoc-Glu(OtBu)-Ser(Psi(Me,Me)Pro)-OH is often defined by its purity. Researchers and manufacturers typically require purity levels of 98% or higher, as verified by analytical techniques such as High-Performance Liquid Chromatography (HPLC) or titration. High purity ensures that side reactions are minimized, and the integrity of the synthesized peptide sequence is maintained, which is especially vital when developing therapeutic peptides where even trace impurities can have significant consequences.

The presence of the Fmoc (9-fluorenylmethoxycarbonyl) group is a key feature, enabling base-labile deprotection, a cornerstone of the Fmoc/tBu SPPS strategy. The tert-butyl (OtBu) ester on the glutamic acid side chain and the pseudoproline modification on the serine residue are designed to enhance the solubility and conformational properties of peptides synthesized using this building block. These specific modifications can lead to improved yields and simplified purification processes.

When looking to buy Fmoc-Glu(OtBu)-Ser(Psi(Me,Me)Pro)-OH, it is imperative to source from reliable manufacturers or distributors. Potential buyers should always request a Certificate of Analysis (CoA) with each batch. The CoA provides lot-specific data, confirming purity, identity, and other critical quality parameters. Safety Data Sheets (SDS) are also essential for understanding safe handling, storage, and disposal procedures.

For R&D departments and procurement teams, identifying suppliers that offer consistent quality, competitive pricing, and responsive customer service is key. Whether sourcing from established international vendors or exploring manufacturers in China, a thorough due diligence process will help ensure that the chosen supplier can consistently meet the stringent requirements of advanced peptide synthesis projects.