Fmoc-O-tert.butyl-trans-4-hydroxy-L-proline

Fmoc-O-tert.butyl-trans-4-hydroxy-L-proline is an Fmoc-protected trans-4-hydroxy-L-proline derivative in which the ring secondary alcohol is masked as an O-tert-butyl ether, preserving the stereodefined proline scaffold for peptide chemistry. The molecule contains a chiral center at the proline α-position and a rigid, conformationally constrained pyrrolidine ring that can influence backbone dihedral angles during amide bond formation and subsequent peptide folding. The Fmoc group provides base-labile N-protection for stepwise solid-phase peptide synthesis, while the tert-butyl ether is acid-labile, enabling orthogonal deprotection sequences to reveal the free 4-hydroxyl functionality when required. The protected alcohol and N-protection combination supports controlled side-chain derivatization, downstream coupling compatibility, and conversion into functionalized proline-based intermediates for synthetic and biochemical research workflows.

1. Peptide Synthesis

Fmoc-O-tert.butyl-trans-4-hydroxy-L-proline is applied in peptide synthesis workflows where a protected proline residue with a masked side-chain hydroxyl is needed to maintain chemoselectivity during chain assembly. The Fmoc-protected nitrogen supports standard peptide coupling strategies, while the trans stereochemistry and rigid pyrrolidine ring help define local backbone conformation in proline-containing sequences. The O-tert-butyl ether prevents uncontrolled hydroxyl participation during activation and coupling steps, enabling reliable incorporation into protected amino acid building blocks. Deprotection can selectively unmask the 4-hydroxyl to generate a handle for subsequent peptide modifications, including further conjugation or derivatization. Proline-based peptide building block preparation using orthogonally protected functional groups aligns with routine amino acid chemistry and scalable peptide manufacture.

2. Side-Chain Functionalization

Fmoc-O-tert.butyl-trans-4-hydroxy-L-proline supports side-chain functionalization strategies through the orthogonal protection pattern that separates N-deprotection from hydroxyl unmasking. The protected 4-hydroxyl can be retained during peptide assembly, then converted into activated derivatives after deprotection to enable esterification, ether formation, or other hydroxyl-reactive transformations. The trans-4-hydroxy proline framework provides a stereochemically defined alcohol position that can be exploited for controlled spatial presentation of functional groups in peptidomimetics and bioactive peptide analogs. Downstream derivatization can generate libraries of proline hydroxyl variants for structure-activity relationship studies and chemical biology probes. The compound therefore functions as a practical intermediate for amino acid derivatization and protected amino acid synthesis routes that require predictable functional group timing.

3. Peptidomimetics And SAR

Fmoc-O-tert.butyl-trans-4-hydroxy-L-proline is utilized in peptidomimetic and SAR-focused chemistry where stereodefined proline residues and a modifiable side-chain hydroxyl are used to tune molecular recognition. The rigid proline ring and trans-4-hydroxy substitution can influence conformational preferences, while the masked hydroxyl enables controlled introduction of polar or conjugatable motifs after scaffold construction. Fmoc protection supports rapid assembly of analog series, and orthogonal deprotection enables generation of hydroxyl-bearing intermediates for systematic comparison of substituent effects. The resulting derivatives can feed into fragment-based molecular design and SAR studies by providing consistent stereochemical points for functional variation. This application direction leverages amino acid chemistry principles to connect protected amino acid building blocks with downstream molecular scaffold generation.

4. Chemical Biology Probes

Fmoc-O-tert.butyl-trans-4-hydroxy-L-proline is suitable for chemical biology probe construction where a proline-based motif bearing a protected hydroxyl is incorporated into labeling-ready peptides or peptide mimics. The Fmoc-protected amine enables stepwise synthesis of probe scaffolds, while the tert-butyl-protected hydroxyl maintains stability during coupling and purification steps that may involve nucleophilic or electrophilic conditions. After selective deprotection, the free 4-hydroxyl can be used to install linkers for fluorophores, affinity tags, or reactive handles for biomolecule modification. The stereodefined trans configuration helps preserve binding-relevant geometry in recognition elements that incorporate proline residues. This enables preparation of biochemical research intermediates that connect amino acid derivatization with biomolecule labeling chemistry.

5. Pharmaceutical Intermediate Preparation

Fmoc-O-tert.butyl-trans-4-hydroxy-L-proline is relevant to pharmaceutical intermediate preparation and fine chemical synthesis where orthogonally protected amino acid derivatives are required for controlled downstream manufacturing of peptide-like structures. The Fmoc group provides a robust N-protection strategy for iterative assembly, and the acid-labile tert-butyl ether supports later unmasking of the 4-hydroxyl to generate a functional intermediate for further synthetic elaboration. The chiral proline scaffold serves as a stereochemically defined input for producing proline-containing intermediates used in process chemistry for peptidomimetic or peptide-derived building blocks. The compound's protected functional groups are compatible with standard synthetic handling of amino acid derivatives, supporting reliable conversion into hydroxyl-reactive intermediates without premature side reactions. Industrially oriented use centers on producing protected amino acid chemistry intermediates that can be carried through multistep synthesis with predictable functional group availability.

1. Effect of Short-Term Desiccation, Recovery Time, and CAPA-PVK Neuropeptide on the Immune System of the Burying Beetle Nicrophorus vespilloides

2. Relatedness of antibodies to peptides containing homocitrulline or citrulline in patients with rheumatoid arthritis

3. Immune responses to peptides containing homocitrulline or citrulline in the DR4-transgenic mouse model of rheumatoid arthritis

4. Extended exenatide administration enhances lipid metabolism and exacerbates pancreatic injury in mice on a high fat, high carbohydrate diet

5. Characterization of Novel P-Selectin Targeted Complement Inhibitors in Murine Models of Hindlimb Injury and Transplantation