Fmoc-Phe(4-Cl)-OH (CAS 142994-19-2), also known as Nα-Fmoc-4-chloro-L-phenylalanine, is a Fmoc-protected unnatural chlorinated phenylalanine analogue of the 4-chlorophenylalanine Fmoc class. The para-chloro substitution on the phenyl ring makes the aromatic side chain much more hydrophobic (π +0.71 vs Phe) and stable in metabolism than natural Phe, and it also changes the electron density. 4-Cl-Phe is used in peptide synthesis to: (1) improve receptor binding affinity by making hydrophobic contacts stronger; (2) slow down P450-mediated aromatic hydroxylation degradation; and (3) be a handle for Pd-catalyzed cross-coupling in on-resin or post-SPPS functionalization (Sonogashira, Suzuki reactions). Applications encompass the synthesis of GnRH antagonist analogues, antimicrobial peptides, and peptidomimetic pharmaceuticals.
ApiSyn sells Fmoc-Phe(4-Cl)-OH (CAS 142994-19-2), a high-quality, pharmaceutical-grade unnatural Fmoc amino acid that can be used to make peptide analogues, improve pharmacokinetics, and check quality.
| Chemical Name | (R)-2-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)-3-(4-chlorophenyl)propanoic acid |
| Molecular Formula | C24H20ClNO4 |
| Molecular Weight | 421.9 |
| CAS Number | 142994-19-2 |