6918
S. Figaroli, A. Madder / Tetrahedron 66 (2010) 6912e6918
temperature for 3 h, after which the resin was washed. The reaction
was repeated once. The photocleavage of a small sample permitted
to obtain the product in solution ready for LC-MS analysis: tR 15.99;
exact mass calculated: 985.6; found m/z 986.6 [MþH]þ.
Member 13: HRMS (ESI) for C125H171N19O20S2: [Mþ2]/2 calcu-
lated 1162.1272, found 1162.1238.
Member 14: HRMS (ESI) for C125H171N19O20S2: [Mþ2]/2 calcu-
lated 1162.1272, found 1162.1226.
Then the product was subjected to Boc deprotection: the resin
(1.08 g, 0.17 mmol/g) was treated with a solution of 20% TFA/DCM
(20 mL/g resin) for 20 min, after which the solution was removed
via filtration and the treatment repeated once. Finally the resin was
washed with a solution of 10% TEA/DCM (ꢁ3) followed by the
standard washing procedure. The deprotection was indicatively
controlled by a NF31 colour test, which gave positive response. The
product (1.08 g, 0.17 mmol/g) was suspended in NMP and the
following reagents were added Fmoc-Gly-OH (0.27 g, 0.91 mmol,
0.5 M), PyBOP (0.47 g, 0.91 mmol, 0.5 M) and DIEA (0.312 mL,
1.82 mmol, 2 N). The reaction mixture was shaken at room
temperature for 3 h, after which the resin was washed and the
reaction repeated once. A small sample was photocleaved for
LC-MS analysis: tR 16.55 min; exact mass calculated 1164.64;
found m/z 1165.6 [MþH]þ.
Member 15: HRMS (ESI) for C125H171N19O20S2: [Mþ2]/2 calcu-
lated 1162.1272, found 1162.1239.
All the RPHPLC-MS chromatograms and spectra are included in
the Supplementary data.
Acknowledgements
This research project has been supported by a Marie Curie Early
Stage Research Training Fellowship of the European Community’s
Sixth Framework Programme under contract number (MEST-CT-
2005-020643).
Supplementary data
Electronic Supplementary data (ESI) available: copies of
RP-HPLC chromatograms and MS spectra for cleaved intermediates
and final library members. Supplementary data associated
with this article can be found in the online version at doi:10.1016/
most important compounds described in this article.
A small amount of resin (90 mg, 0.17 mmol/g) underwent Fmoc
deprotection yielding product 7.
The resin was split in six reaction vessels (2 mL) to perform the
automated synthesis for the preparation of six members.
5.4.6. Automated synthesis. All reactions occurred at room tem-
perature, without protecting atmosphere; the necessary solutions
were prepared manually.
References and notes
First, the synthesis of the six different members was pro-
grammed. The automated synthesis started with a 10 min swelling
step followed by coupling of the first amino acid. During the
automated coupling the correct amino acid is transferred in the
corresponding plastic reactor, which is then filled with HBTU and
DIPEA and swirled for 1 h; each coupling step is followed by Fmoc
removal. After the coupling and Fmoc deprotection of the final
amino acid of the first peptide chain, a capping step was carried out
(8). Next, the azide moiety was reduced to amino group treating the
resin with Me3P (0.75 M THF/H2O) and leaving it to react for 2 h,
this treatment was repetes once. The supports were thoroughly
1. Blair, R. M.; Fang, H.; Branham, W. S.; Hass, B. S.; Dial, S. L.; Moland, C. L.; Tong,
W. D.; Shi, L. M.; Perkins, R.; Sheehan, D. M. Toxicol. Sci. 2000, 54, 138e153.
2. Preziosi, P. Pure Appl. Chem. 1998, 70, 1617e1631.
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6. Brzozowski, A. M.; Pike, A. C. W.; Dauter, Z.; Hubbard, R. E.; Bonn, T.; Engstrom, O.;
Ohman, L.; Greene, G. L.; Gustafsson, J. A.; Carlquist, M. Nature 1997, 389, 753e758.
7. Shiau, A. K.; Barstad, D.; Loria, P. M.; Cheng, L.; Kushner, P. J.; Agard, D. A.;
Greene, G. L. Cell 1998, 95, 927e937.
8. Abad, M. C.; Askari, H.; O’Neill, J.; Klinger, A. L.; Milligan, C.; Lewandowski, F.;
Springer, B.; Spurlino, J.; Rentzeperis, D. J. Steroid Biochem. Mol. Biol. 2008, 108,
44e54.
9. Anstead, G. M.; Carlson, K. E.; Katzenellenbogen, J. A. Steroids 1997, 62, 268e303.
10. Van der Plas, S. E.; Van Hoeck, E.; Lynen, F.; Sandra, P.; Madder, A. Eur. J. Org.
Chem. 2009, 1796e1805.
11. Barry, J. F.; Davis, A. P.; Perez-Payas, M. N.; Elsegood, M. R. J.; Jackson, R. F. W.;
Gennari, C.; Piarulli, U.; Gude, M. Tetrahedron Lett. 1999, 40, 2849e2852.
12. Maitra, U. Org. Biomol. Chem. 2008, 6, 657e669.
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Chem. Soc. 2002, 124, 5276e5277.
i
washed with PrOH and DMF, then swollen in DMF. The second
peptide chain was synthesized as the first one but no capping was
carried out to allow a better ionization of the product during mass
analysis. This protocol allowed to obtain products from 10 to 15.
Preparation of coupling reagents solutions: Fmoc-protected
amino acid (5 equiv, 0.5 M in DMF except for Fmoc-Phe-OH
dissolved in NMP), HBTU (5 equiv, 0.5 M in DMF) and DIEA
(10 equiv, 2 M in NMP).
Preparation of the solutions for Fmoc deprotection (40% piper-
idine/NMP), capping (Ac2O/Py/NMP 1: 3: 5), azide reduction Me3P
(5 equiv, 0.75 M THF/H2O).
14. Davis, A. P.; Wareham, R. S. Angew. Chem., Int. Ed. 1999, 38, 2978e2996.
15. De Muynck, H.; Madder, A.; Farcy, N.; De Clercq, P. J.; Perez-Payan, M. N.;
Ohberg, L. M.; Davis, A. P. Angew. Chem., Int. Ed. 2000, 39, 145e148.
16. Madder, A.; Li, L.; De Muynck, H.; Farcy, N.; Van Haver, D.; Fant, F.; Vanhoenacker,
G.; Sandra, P.; Davis, A. P.; De Clercq, P. J. J. Comb. Chem. 2002, 4, 552e562.
17. Bode, C. A.; Bechet, T.; Prodhomme, E.; Gheysen, K.; Gregoir, P.; Martins, J. C.;
Muller, C. P.; Madder, A. Org. Biomol. Chem. 2009, 7, 3391e3399.
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All library members (from 10 to 15) were analyzed by RPHLC-MS
and HRMS.
Here below the HRMS data are reported:
19. Holmes, C. P. J. Org. Chem. 1997, 62, 2370e2380.
Member 10: HRMS (ESI) for C125H171N19O20S2: [Mþ2]/2 calcu-
20. Verzele, D.; Goeman, J. L.; Madder, A. Arkivoc 2007, 10, 325e336.
21. Madder, A.; Farcy, N.; Hosten, N. G. C.; De Muynck, H.; De Clercq, P. J.; Barry, J.;
Davis, A. P. Eur. J. Org. Chem. 1999, 2787e2791.
22. Banaszynski, L. A.; Liu, C. W.; Wandless, T. J. J. Am. Chem. Soc. 2005,127, 4715e4721.
23. Handbook of Reactive Chemical Hazards, 7th ed.; Urben, P. G, Ed.; Academic
Press: Amsterdam, 2007.
lated 1162.1272, found 1162.1301.
Member 11: HRMS (ESI) for C125H171N19O20S2: [Mþ2]/2 calcu-
lated 1162.1272, found 1162.1224.
Member 12: n.d.