1. The synthesis, distribution, and anti-hepatic cancer activity of YSL
Wenfeng Ding, Jiali Zhang, Zhi Yao, Rong Lu, Dezhu Wu, Ginfu Li, Zilong Shen, Yingji Sun, Gang Lin, Chao Wang, Ming Zhao, Shiqi Peng Bioorg Med Chem. 2004 Sep 15;12(18):4989-94. doi: 10.1016/j.bmc.2004.06.030.
YSL was prepared stepwise from C terminal to N terminal with the side chain un-protective amino acids, Boc-Leu-OMe, Boc-Ser-OH, and Boc-Tyr-OH, as the starting materials in 39.5% total yield (31.2g/per batch). With the side chain un-protective Boc-(3,5-dibromo)-Tyr-OH and HCl.Ser-Leu-OMe as the starting materials (3,5-(3)H-Tyr)-Ser-Leu-OH was obtained in 29% yield. The determination of radioactive quantity in the urine and feces indicated that even after the administration for 130 h only 8.4% (5.35% in urine and 3.05% in feces) of total radioactive quantity from the metabolite of [3,5-(3)H-Tyr]-Ser-Leu-OH were monitored. The distribution study revealed the relative accumulation level of the individual tissue was arranged in the sequence of spleen>liver>kidney>lung>heart>muscle>brain. Selecting hepatic cancer as the target YSL significantly increased the survival time of H22 tumor cells implanted mice.
2. Epimerization free synthesis of O-acyl isodipeptides employing COMU
M Samarasimhareddy, Hosahalli P Hemantha, Kuppanna Ananda, Vommina V Sureshbabu Protein Pept Lett. 2012 Apr;19(4):406-10. doi: 10.2174/092986612799789413.
O-Acyl isodipeptides are prepared by coupling Boc-Ser/Thr-OBzl with Fmoc-Xaa-OH employing COMU, well known third generation peptide coupling agent. The reaction proceeds with high yield and the chemical homogeneity of the synthesized molecules were established via chiral HPLC analyses. The O-acyl isodipeptide units play crucial role in the success of ' click peptide' protocol employed for assembling ' difficult sequence' peptides.
3. "O-acyl isopeptide method" for peptide synthesis: synthesis of forty kinds of "O-acyl isodipeptide unit" Boc-Ser/Thr(Fmoc-Xaa)-OH
Taku Yoshiya, et al. Org Biomol Chem. 2007 Jun 7;5(11):1720-30. doi: 10.1039/b702284k. Epub 2007 Apr 25.
The O-acyl isopeptide method has recently received attention as an efficient synthetic method for peptides. Herein, forty kinds of "O-acyl isodipeptide unit" Boc-Ser/Thr(Fmoc-Xaa)-OH (1-40) were effectively synthesized in two-steps without epimerization. The O-acyl isodipeptide units are important building blocks to enable the routine use of the O-acyl isopeptide method.
