71989-38-3

white to light yellow crystalline powder; insoluble in water and petroleum ether, soluble in ethyl acetate, methanol and DMF; mp is 150-151°C; specific optical rotation [α] 20D + 5.2° (0.5-2.0mg/ml, ethyl acetate ), [α]20D-27.6° (0.5-2.0 mg/ml, DMF), [α]20D-6° (0.5-2.0 mg/ml, methanol).

Fmoc-Tyr(tBu)-OH is used in peptide synthesis as amino acid protection monomer.

To obtain Fmoc-Tyr(tBu)-OH, the following steps are carried out:
Suspend O-tert-butyl-L-tyrosine in a solution of dioxane.
Conduct an acylation reaction with fluorenyl methaneoxycarbonyl azide.
After the reaction, extract the crude product with ethyl acetate under pH 9-10 conditions.
Purify the extracted product through recrystallization.
This process results in the final product, Fmoc-Tyr(tBu)-OH.

Fmoc-Tyr(tBu)-OH is the preferred tyrosine derivative for solid phase peptide synthesis by Fmoc protocols. Protecting the Tyr sidechain may not be essential in the synthesis of small peptides. If the phenolic functional group of tyrosine does become acylated during a coupling reaction, the subsequent treatment with piperdine to remove Fmoc-groups will also remove any acylation of the phenolic function. Using Fmoc-Tyr(tBu)-OH in peptide synthesis is more efficient, however, since none of the activated amino acids are used unproductively in acylating exposed tyrosine side-chains. The use of Fmoc-Tyr(tBu)-OH also eliminates all potential for side products arising from the acylation of the tyrosine side-chain.