Fmoc-Tyr

Fmoc-Tyr[PO(OMe)2]-OtBu (4) was prepared as described for compound 2 by phosphorylation of Fmoc-Tyr-OtBu (lO.Ommol) and was obtained as a light yellow oil. 

Scheme 3 Fmoc-Based Solid-Phase Synthesis of RLIEDNEY(P)TARQG Using Fmoc-Tyr[PO(OMe)2]-OH 2lll...

A major advancement in the Fmoc-based solid-phase synthesis of Tyr(P)-peptides was realized with the Fmoc-Tyr[PO(OR1)2]-OH derivatives 7 (R1 = Bzl, tBu, Mdpse) [Mdpse = 2-(methyldiphenylsilyl)ethyl] in which the acid-labile phosphate esters offered simple cleavage by TFA treatment. While the initial difficult synthesis of derivatives 7 restricted general synthetic usage, the subsequent commercial availability of these derivatives and their compatibility with solid-phase synthesis has provided a simple and efficient procedure for the routine synthesis of large complex Tyr(P)-peptides. 

Scheme 4 Synthesis of Fmoc-Tyr[PO(OBzl)2]-OH and Fmoc-Tyr[PO(OtBu)2]-OHt331...

Fmoc-Tyr[PO(OBzl)2]-OH was prepared as described for derivative 7 (R1 = tBu) using dibenzyl diethylphosphoramidite (9.51 g, 30.0 mmol) (note, the Na salt of the benzyl derivative partially separates... 

Table 3 Tyr(P)-Peptides Prepared Using Fmoc-Tyr[PO(OR )2]-OH Derivatives112-21...

Fmoc—Tyr—OPac--------------------------------------------- Fmoc—Tyr[PO(OBzl)(OTce)]—OPac... 

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