Fmoc-Thr(tBu)-ol

White to off-white powder

Fmoc-Thr(tBu)-OL is a very light yellow oily liquid. The compound serves as a precursor for Tyr3-octreotide peptide synthesis, where it is anchored to 2-chlorotrityl chloride resin[1-2].

Fmoc-Thr(tBu)-OL is prepared from Fmoc-Thr(tBu)-OH by HATU activation of the carboxyl group followed by reduction to the hydroxyl group with sodium borohydride, giving a 72.4% yield[1]. Alternatively, the carboxyl group of Fmoc-Thr(tBu)-OH is activated with N-methylmorpholine and isobutyl chloroformate at −15 °C and then reduced with NaBH4, affording Fmoc-Thr(tBu)-OL as a white solid in 70.9% yield[2].

[1] Assad, T., Mansour, R., Abou Hajar, I. (2017). Synthesis of Hynic-TOC Peptide and Label it with 99mTc to be used in Tumor Diagnosis, and Synthesis and characterize of amino acids: Fmoc-Asp(OtBu)- OL, Fmoc-Glu(OtBu)- OL and Fmoc-Thr(tBu)- OL.
[2] Arano, Y., Akizawa, H., Uezono, T., Akaji, K., Ono, M., Funakoshi, S., Koizumi, M., Yokoyama, A., Kiso, Y., Saji, H. (1997). Conventional and High-Yield Synthesis of DTPA-Conjugated Peptides:  Application of a Monoreactive DTPA to DTPA-d-Phe¹-octreotide Synthesis. Bioconjugate Chemistry, 8(3), 442–446. https://doi.org/10.1021/bc970023b