Fmoc-Tyr(tBu)-OH Chemical Properties

Melting point:

~150 °C (dec.)

alpha 

-28 º (c=1, DMF)

Boiling point:

658.2±55.0 °C(Predicted)

Density 

1.218±0.06 g/cm3(Predicted)

refractive index 

-30 ° (C=1, DMF)

storage temp. 

Store below +30°C.

solubility 

Chloroform (Slightly), DMF (Slightly), Methanol (Slightly)

form 

Powder

pka

2.97±0.10(Predicted)

color 

White

optical activity

[α]20/D 29±2°, c = 1% in DMF

BRN 

4216652

InChIKey

JAUKCFULLJFBFN-VWLOTQADSA-N

SMILES

C(O)(=O)[C@H](CC1=CC=C(OC(C)(C)C)C=C1)NC(OCC1C2=C(C=CC=C2)C2=C1C=CC=C2)=O

CAS DataBase Reference

71989-38-3(CAS DataBase Reference)

Safety Information

Hazard Codes 

Xi

Risk Statements 

36/37/38

Safety Statements 

26-24/25

WGK Germany 

3

HS Code 

2924 29 70

MSDS

• Language:English Provider:Fmoc-O-tert-butyl-L-tyrosine
• Language:English Provider:SigmaAldrich

Fmoc-Tyr(tBu)-OH Usage And Synthesis

Chemical Properties

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).

Uses

Fmoc-O-tert-butyl-L-tyrosine belongs to L-tyrosine compounds. Its molecular structure contains a chiral center, so it can exist two enantiomers and has optical activity. Fmoc-Tyr(tBu)-OH is used in peptide synthesis as amino acid protection monomer.

Preparation

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.

General Description

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.

reaction suitability

reaction type: Fmoc solid-phase peptide synthesis

Synthesis

1. 500 g of deionized water and about 60 g of tetrahydrofuran (THF) were added to a reaction flask. 2. 299 g of O-tert-butyl-L-tyrosine (L-Tyr(tBu)) and 150 g of sodium carbonate (Na2CO3) were added and stirred until fully dissolved. 3. 300 g of chloroformic acid-9-fluorenylmethyl ester (9-fluorenylmethoxycarbonyl chloride) was slowly added under stirring while monitoring the pH of the reaction system, maintaining pH=9. 4. The progress of the reaction was monitored by thin layer chromatography (TLC) until L-Tyr(tBu) was fully reacted. 5. Upon completion of the reaction, the product was extracted with 300 g of ethyl acetate (AcOEt). 6. The organic phases were combined and washed several times with saturated saline. 7. The pH of the aqueous phase was adjusted to 3 with citric acid and the product was again extracted with ethyl acetate. 8. All organic phases were combined and dried over 50 g of anhydrous sodium sulfate (Na2SO4). 9. 9. The desiccant was removed by filtration and the filtrate was concentrated under reduced pressure to 1/4 of the original volume. 10. After cooling, 200 g of petroleum ether (PET) was added to induce crystallization and the solid product was collected by filtration. 11. 450 g of Fmoc-O-tert-butyl-L-tyrosine (Fmoc-Tyr(tBu)) was obtained after drying in 80.1% overall yield. 12. product properties: white powder. 12. Product properties: white powder; HPLC purity 99% (area normalized); melting point 150 °C; moisture content 1% (Karl Fischer method); specific optical rotation -18.9; single impurity content 0.3% (% HPLC area); optical purity 99.98%.

References

[1] Patent: CN103833593, 2016, B. Location in patent: Paragraph 0045; 0050

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