1. New C-protective group for peptide synthesis. Application of 2-(1-adamantyl)-propanol-2 esters
G Cipens, L Brivkalne, I Sekacis, I Mutule, J Balodis, F Mutulis Int J Pept Protein Res . 1993 Sep;42(3):233-9. doi: 10.1111/j.1399-3011.1993.tb00137.x.
To investigate the possibility of using the 2-(1-adamantyl)-2-propyl (Adp) ester group for carboxyl protection during peptide synthesis, the tetrapeptide Boc-Phe-Arg(NO2)-Phe-Pro-OAdp (IV) was prepared by the carbodiimide method. In this synthesis the Z group was removed by transfer hydrogenation and the Nps group by treatment with 2-thiopyridone. The Adp group was then cleaved with 3% TFA/DCM, yielding Boc-Phe-Arg(NO2)-Phe-Pro-OH. For subsequent kinetics studies the decapeptide Boc-Leu--Z-Orn-Arg(NO2)-Pro- Pro-Gly-Phe-Ser(Bzl)-Pro-Pro-OAdp (VIII) was synthesized by a 9 + 1 scheme. This peptide was also selectively deblocked. Comparing reaction abilities of Z-Pro-OAdp and Z-Pro-OBut, it was demonstrated that the Adp ester is cleaved by 3% TFA/DCM 230 times faster than the Bu(t) ester. For peptides IV and VIII the ratios between the rates of competitive elimination of the Adp and Boc groups by 3% TFA/DCM are 19 and 64, respectively.
2. Human proinsulin VI. Synthesis of protected segment 46-70 of prohormone
E Schwertner, V K Naithani Hoppe Seylers Z Physiol Chem . 1983 Nov;364(11):1603-13. doi: 10.1515/bchm2.1983.364.2.1603.
The synthesis of the protected pentacosapeptide Trt-Gly-Gly-Pro-Gly-Ala-Gly-Ser-(But)-Leu-Gln-Pro-Leu-Ala-Leu-Glu( OBut)-Gly-Ser (But)-Leu-Gln-Lys(Boc)-Arg-Gly-Ile-Val-Glu-(OBut)-Gln-OH (Pos. 46-70) of human proinsulin is described. This segment was prepared by the mixed anhydride condensation of the trityl-protected peptides (46-64) or (46-59) with the fragments 65-70 and 60-70, respectively. In both the cases the purification was effected by counter current distribution in a yield of 25% and 24%, respectively.
3. Synthetic insulin by selective disulfide briding, II. Polymer phase synthesis of the human B chain fragments
C Birr, C Voss Hoppe Seylers Z Physiol Chem . 1981 Jun;362(6):717-25. doi: 10.1515/bchm2.1981.362.1.717.
Five protected fragments Ddz-Phe-Val-Asn(Mbh)-Gln(Mbh)-His(Dnp)-Leu-Cys(Acm)-Gly-OH [I], Ddz-Ser(But)-His(Dnp)-Leu-Val-Glu-(OBut)-Ala-OH [II], Ddz-Leu-Tyr(But)-Leu-Val-Cys(Mbzl)-Gly-OH [III], Ddz-Glu(OBut)-Arg(Tos)-Gly-OH [IV], Ddz-Phe-Phe-Tyr(But)-thr(But)-Pro-Lys(Z)-Thr(But)-OH [V] for the synthesis of the human insulin B chain, were prepared by an efficient procedure on solid phase.
