Page 5 of 6
Organic & Biomolecular Chemistry
DOI: 10.1039/C4OB02046D
LL and DL epimers were 6.79 and7.95 min, respectively. LC–MS
showed the expected mass for the tripeptide at m/z = 325.0.
expected mass for the decapeptide at m/z = 1090, desꢀAib at m/z
= 1005, desꢀAibꢀIle72 at m/z = 892 and desꢀGlnat m/z = 963.
33, 35, 37
Solid-Phase Synthesis of H-Tyr-Aib-Aib-Phe-Leu-NH2
60 Acknowledgements
The synthesis was carried out in a plastic syringe, attached to a
vacuum manifold so as to effect rapid removal of reagents and
solvent. The FmocꢀRinkAmideꢀAMꢀPEG resin (0.58 mmolg–1, 50
mg)was washed with DMF, DCM, and DMF (2×10 mL each) and
then treated with 20% piperidine in DMF (10 mL) for 10 min.
The resin was then washed with DMF and DCM, and then with
We thank Yoav Luxembourg (Luxembourg Bio Technologies
Ltd.) for his continuous support of this study, Dr. Ariel Ewenson
(Luxembourg Ind.,) for sharing information about REACH, and
Dr. Karine Salim (Pcas) for the generous gift of ChemMatrix
65 resin. This work was funded in part by the following: the
National Research Foundation (NRF) and the University of
KwaZulu Natal (South Africa); SENESCYT (Ecuador); the
CICYT (CTQ2012ꢀ30930), the Generalitat de Catalunya (2014
SGR 137), and the Institute for Research in Biomedicine
70 Barcelona (IRB Barcelona) (Spain). Additionally, the authors
thank the Deanship of Scientific Research at King Saud
University for partially funding this work throughresearch group
no. RGPꢀ234 (Saudi Arabia).
5
10 solvent used during the coupling step (2×10 mL each). The resin
was thenacylated with a solution of FmocꢀLeuꢀOH (3 equiv.), the
corresponding additive (3 equiv.) and DIC (3 equiv.) in minimum
amount of solvent (DMF, THF or ACN) at room temperature and
preactivated for 3 min. After peptide coupling, the resin was
15 washed with DMF, DCM, and DMF and then deblocked by
treatment with 20% piperidine in DMF for 7 min. Next, washing
and coupling with the next amino acid, as explained before, and
deblocking, was repeated to obtain the pentapeptide. The peptide
was cleaved from the resin with TFA/H2O (9:1) at room
20 temperature for 2 h. TFA was removed under nitrogen, and the
crude peptide was purified with cold Et2O (3×10 mL) and
lyophilized. The ratio of the pentaꢀ and tetraꢀpeptide was
determined by HPLC analysis by using a Phenomex C18 (3 ꢁm,
4.6 × 50 mm) column, with a linear gradient of 20 to 40% of
25 0.1% TFA in CH3CN/0.1 %TFA in H2O over 15 min, flow rate =
1.0 mLmin–1, detection at 220 nm. The tR values for pentapepide
and desꢀAib were 6.68 min and 6.78 min, respectively. LC–MS
showed the expected mass for the pentapeptide at m/z = 611.0,
and also for desꢀAib at m/z = 526.
Notes and references
75 aCatalysis and Peptide Research Unit, School of Health Sciences,
University ofKwazuluꢀNatal, Durban 4001, South Africa.
bInstitute for Research in BiomedicineꢀBarcelona,08028ꢀBarcelona,
cCIBERꢀBBN, Networking Centre on Bioengineering, Biomaterials and
80 Nanomedicine, Barcelona Science Park, 08028ꢀBarcelona, Spain
dDepartment of Chemistry, Faculty of Science, Alexandria UniversityP.O.
Box 426, Ibrahimia, Alexandria 21321, Egypt.Eꢀmail:
eSchool of Chemistry, Yachay Tech, Yachay City of Knowledge, 100119ꢀ
fDepartment of Chemistry, College of Science, King Saud UniversityP.O.
Box 2455,Riyadh11451, Saudi Arabia
30 Solid-Phase Synthesis of Aib67, Aib68-modified ACP (65-74)
decapeptide [H-Val-Gln-Aib67-Aib68-Ile-Asp-Tyr-Ile-Asn-Gly-
NH2]35, 36
g School of Chemistry and Physics, University ofKwazuluꢀNatal, Durban
4001, South Africa
90 hDepartment of Organic Chemistry, University of Barcelona, 08028ꢀ
Barcelona, Spain
The synthesis was carried out in a plastic syringe, attached to a
vacuum manifold so as to effect rapid removal of reagents and
35 solvent. The FmocꢀRinkAmideꢀAMꢀPEG resin (0.52 mmolg–1, 50
mg), was washed with DMF, DCM, and DMF (2×10 mL each)
and then treated with 20% piperidine in DMF (10 mL) for 10
min. The resin was then washed with DMF, and DCM, and then
with the solvent used during the coupling step(2×10 mL each).
40 The resin was thenacylated with a solution of FmocꢀGlyꢀOH (3
equiv.), the corresponding additive (3 equiv.), and DIC (3 equiv.)
in minimum amount of solvent (DMF, THF or ACN) at room
temperature and preactivated for 3 min. After peptide coupling,
the resin was washed with DMF and then deblocked by treatment
45 with 20% piperidine in DMF for 7 min. Next, washing and
coupling with the next amino acid, as explained before, and
deblocking, was repeated to obtain the decapeptide. The peptide
was cleaved from the resin with TFA/H2O (9:1) at room
temperature for 2 h. TFA was removed under nitrogen, and the
50 crude peptide was purified with cold Et2O (3×10 mL) and
lyophilized. The purity of product was determined by HPLC
analysis by using a Phenomex C18 (3 ꢁm, 4.6 × 50 mm) column,
with a linear gradient of 10 to 50% of 0.1% TFA in CH3CN/0.1
%TFA in H2O over 15 min, flow rate = 1.0 mLmin–1, detection at
55 220 nm. The tR values for decapepide, desꢀAib, desꢀAibꢀIle72 and
desꢀGln were 6.8 (decapeptide), 6.9(desꢀAib), 4.5 (desꢀAibꢀIle72)
and 7.8 min (desꢀGln), respectively. LC–MS showed the
&Although the term “green” could not be strictly applied to THF and
ACN, both could be more considered “greener” or the friendlier use than
DMF
95 † Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/b000000x/
1.
2.
3.
T. Cupido, J. TullaꢀPuche, J. Spengler and F. Albericio, Curr.
Opin. Drug Discovery Dev., 2007, 10, 768ꢀ783.
A. A. Zompra, A. S. Galanis, O. Werbitzky and F. Albericio,
Future Med. Chem., 2009, 1, 361ꢀ377.
A. K. Ghose, V. N. Viswanadhan and J. J. Wendoloski, J.
Comb. Chem., 1999, 1, 55ꢀ68.
100
105 4.
R. W. Dugger, J. A. Ragan and D. H. B. Ripin, Org. Process
Res. Dev., 2005, 9, 253ꢀ258.
5.
J. S. Carey, D. Laffan, C. Thomson and M. T. Williams, Org.
Biomol. Chem., 2006, 4, 2337ꢀ2347.
6.
110
S. D. Roughley and A. M. Jordan, J. Med. Chem., 2011, 54,
3451ꢀ3479.
7.
D. S. MacMillan, J. Murray, H. F. Sneddon, C. Jamieson and
A. J. B. Watson, Green Chem., 2013, 15, 596ꢀ600.
F. Albericio and L. A. Carpino, in Methods Enzymol., ed. B. F.
Gregg, Academic Press, 1997, vol. Volume 289, pp. 104ꢀ126.
S.ꢀY. Han and Y.ꢀA. Kim, Tetrahedron, 2004, 60, 2447ꢀ2467.
C. A. G. N. Montalbetti and V. Falque, Tetrahedron, 2005, 61,
10827ꢀ10852.
8.
115 9.
10.
11.
E. Valeur and M. Bradley, Chem. Soc. Rev., 2009, 38, 606ꢀ
631.
120 12.
A. ElꢀFaham and F. Albericio, Chem. Rev., 2011, 111, 6557ꢀ
6602.
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 |5