Products

Boc-Pip(Fmoc)-OH (4-(Boc-amino)-1-Fmoc-piperidine-4-carboxylic acid, CAS 368866-07-3) is a conformationally constrained unnatural amino acid derivative built upon a piperidine ring system. The molecule features a piperidine-4-carboxylic acid core with two orthogonal protecting groups: a tert-butoxycarbonyl (Boc) group protecting the 4-amino nitrogen, and a 9-fluorenylmethoxycarbonyl (Fmoc) group protecting the ring nitrogen at the 1-position.

Fmoc-Sar-OH.H2O is the Fmoc‑protected form of sarcosine (N‑methylglycine), supplied as the monohydrate crystalline form. Sarcosine is the simplest N‑alkylated amino acid, featuring a secondary amino group (—NH—) in place of the primary amino group found in standard α‑amino acids. This structural difference fundamentally alters the conformational behavior of sarcosine‑containing peptides: the N‑methyl group restricts backbone flexibility, reduces the propensity for hydrogen‑bonding, and imparts unique secondary structure preferences not accessible with conventional amino acid residues.

Fmoc-N-Me-Trp(Boc)-OH (N-α-(9-Fluorenylmethoxycarbonyl)-N-α-methyl-N-in-tert-butoxycarbonyl-L-tryptophan, CAS 197632-75-0) is a di-protected N-methylated tryptophan derivative designed for Fmoc-based solid-phase peptide synthesis (SPPS). The molecule incorporates three key structural features: an Fmoc group protecting the α-amino function, an N-methyl group at the α-nitrogen, and a Boc group protecting the indole nitrogen of the tryptophan side chain.

Fmoc-Asp(OMpe)-OH (N-α-Fmoc-L-aspartic acid β‑3‑methylpent‑3‑yl ester) is an Fmoc‑protected L‑aspartic acid derivative bearing the sterically demanding β‑3‑methylpent‑3‑yl (OMpe) side‑chain protecting group. The compound was specifically developed as an advanced alternative to the standard Fmoc‑Asp(OtBu)‑OH for use in Fmoc solid‑phase peptide synthesis (SPPS), where repetitive piperidine treatment during Fmoc deprotection can otherwise trigger extensive aspartimide‑related by‑product formation at aspartyl residues, particularly in Asp‑Gly, Asp‑Ser, and Asp‑Thr sequences.

Fmoc-TmbGly-OH is a specialized dual‑protected glycine derivative featuring a 2,4,6‑trimethoxybenzyl (Tmb) group on the backbone amide nitrogen, in addition to the standard base‑labile Fmoc protecting group on the terminal amine. This structural innovation positions Fmoc-TmbGly-OH as a member of the benzyl‑based backbone protecting group family, which includes the 2,4‑dimethoxybenzyl (Dmb) and 2‑hydroxy‑4‑methoxybenzyl (Hmb) analogues. In the native Fmoc solid‑phase peptide synthesis (SPPS) of glycine‑containing peptides, the high conformational flexibility of glycine makes peptide chains prone to intermolecular aggregation on solid supports — leading to incomplete deprotection, slow coupling kinetics, and ultimately low crude peptide yields and purities. Fmoc-TmbGly-OH addresses this challenge through strategic backbone protection that disrupts hydrophobic aggregation during chain assembly, while its enhanced acid lability (cleaved with as little as 7% TFA) marks a strategic upgrade from Fmoc-(Dmb)Gly-OH, enabling selective orthogonal deprotection for complex, high‑value peptide targets.

Fmoc-Lys(Mmt)-OH (Nα-Fmoc-Nε-4-methoxytrityl-L-lysine) is an orthogonally protected lysine derivative featuring a highly acid‑labile 4‑methoxytrityl (Mmt) protecting group on the ε‑amino side chain. The molecule consists of a base‑labile Fmoc group installed at the α‑amino terminus, a bulky and highly electron‑rich methoxytrityl group protecting the ε‑amine of the lysine side chain, and a free α‑carboxylate for coupling. The Mmt group is significantly more acid‑labile than traditional protecting groups such as Boc or Trt, and can be selectively removed under extremely mild acidic conditions (1% TFA in DCM) that leave all other standard acid‑labile protecting groups intact. This extraordinary acid sensitivity makes Fmoc-Lys(Mmt)-OH an excellent building block for the synthesis of branched peptides, cyclic peptides, and complex multifunctionalized peptide conjugates via Fmoc solid‑phase peptide synthesis.