Description
Fmoc-Tyr(Me)-OH, also known as Fmoc-O-methyl-L-tyrosine, is an Fmoc protected tyrosine derivative that is potentially useful for proteomics studies and solid phase peptide synthesis techniques. Tyrosine is a important amino acid - one of the few amino acids which is phosphorylated to vary the physical properties of the peptides, and is a precursor for the formation of iodinated thyroid hormones. The Fmoc group is typically removed with a base such as pyridine - an orthogonal de-protection strategy to the acid labilie Boc group.
Synthesis
Fmoc-Tyr(Me)-OH, also known as Fmoc-Tyr(OMe)-OH, was obtained from Fmoc-Tyr(OMe)-OMe within 1h and was isolated following protocol 1 or 2 in 96% yield[1]. Under argon atmosphere, anhydrous THF (2.0 mL) was added to the protected amino acid Fmoc-Tyr(OMe)-OMe (0.12 mmol) and to MgI2 * (1.2 mmol). The suspension was heated in a sealed reactor using microwave irradiation at 120°C. A Na2S2O3 aqueous solution (0.1 M) was then added and the resulting homogeneous mixture was directly analysed by analytical HPLC and LC/MS. To isolate the product, two protocols could be applied:
Protocol 1: The crude material was purified by preparative HPLC.
Protocol 2: The crude material was extracted with AcOEt (x3). The organic layer was washed with brine, dried over MgSO4, filtered and concentrated under reduced pressure. The residue was diluted in H2O/EtOH and lyophilized.
References
[1] Berthet M, et al. MgI2 -Mediated Chemoselective Cleavage of Protecting Groups: An Alternative to Conventional Deprotection Methodologies. Chemistry - A European Journal, 2015; 21: 11014-11016.
