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DOI: 10.1055/s-2003-38361
Synthesis of Methionine Containing Peptides Related to Native Chemical Ligation
Publication History
Publication Date:
28 March 2003 (online)

Abstract
Methionine chemical ligation is based on a convenient direct thioester formation at the C-terminus of the ligation site, on homocysteine reduction with dithiothreitol in order to liberate the mercapto group of the homocysteine residue at the N-terminus, and on chemoselective S-methylation with methyl iodide.
Key words
chemical ligation - methionine ligation - peptides - S-methylation
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1a
Dawson PE.Kent SBH. Annu. Rev. Biochem. 2000, 69: 923 -
1b
Tam JP.Yu Q.Miao Z. Biopolymers 1999, 51: 311 -
1c
Wilken J.Kent SBH. Curr. Opin. Biotechnol. 1998, 9: 412 -
1d
Hang HC.Bertozzi CR. Acc. Chem. Res. 2001, 34: 737 -
1e
Muir TW. Synlett 2001, 733 -
1f
Goody RS.Alexandrov K.Engelhard M. ChemBioChem 2002, 3: 399 - 2
Wieland T.Bokelmann E.Bauer L.Lang HU.Lau H. Liebigs Ann. Chem. 1953, 583: 129 - 3
Dawson PE.Muir TW.Clark-Lewis I.Kent SBH. Science 1994, 266: 776 -
4a
Shao Y.Lu W.Kent SBH. Tetrahedron Lett. 1998, 39: 3911 -
4b
Camarero JA.Muir TW. Chem. Commun. 1997, 1369 -
4c
Zhang L.Tam JP. J. Am. Chem. Soc. 1997, 119: 2363 - 5
Canne LE.Bark SJ.Kent SBH. J. Am. Chem. Soc. 1996, 118: 5891 - 6
Offer J.Dawson PE. Org. Lett. 2000, 2: 23 - 7
Yan LZ.Dawson PE. J. Am. Chem. Soc. 2001, 123: 526 -
8a
Hondal RJ.Nilsson BL.Raines RT. J. Am. Chem. Soc. 2001, 123: 5140 -
8b
Gieselman MD.Xie L.van der Donk WA. Org. Lett. 2001, 3: 1331 -
8c
Saxon E.Armstrong JI.Bertozzi CR. Org. Lett. 2000, 2: 2141 -
8d
Quaderer R.Hilvert D. Chem. Commun. 2002, 2620 -
8e
Nilsson BL.Kiessling LL.Raines RT. Org. Lett. 2000, 2: 1939 - 9
Tam JP.Yu Q. Biopolymers 1998, 46: 319 - 12
Or YS.Clark RF.Luly JR. J. Org. Chem. 1991, 56: 3146 - 13
Yang CC.Marlowe CK.Kania R. J. Am. Chem. Soc. 1991, 113: 3177 - 14
Kasafirek E.Fukal L.Kas J. Collect. Czech. Chem. Commun. 1988, 53: 3197 - 15
Marastoni M.Salvadori S.Balboni G.Scaranari V.Santagada V. Arzneim. Forsch. 1991, 41: 240 - 16
Henklein P.Boomgaarden M.Nieke E.-M.Georgi M.Niedrich H. Pharmazie 1988, 43: 10
References
General Procedure for the Synthesis of Peptides 8-14, 16: To a stirred solution of homocystine (200 mg, 0.75 mmol) in 0.1 M Tris buffer (10 mL, pH ca. 8.0) containing 6 M guanidinium hydrochloride was added DTT (230 mg, 1.5 mmol) and the reaction mixture was allowed to stir at r.t. After 1 h, thioester (1.5 mmol) was added to the reaction mixture. After completion of the reaction (TLC monitoring), the reaction mixture was washed with CHCl3 and the aq layer was neutralized with dilute HCl; the aq layer was then extracted with EtOAc followed by washing the EtOAc layer with brine and the organic layer was dried over anhyd Na2SO4. Evaporation of the solvent yielded the corresponding crude thiol, which was purified by recrystallization. This thiol was immediately taken up in NH3 in MeOH (3 mL) and MeI (3 equiv) was added into the reaction mixture at 0 °C. This reaction mixture was allowed to stir at 0 °C for 2.0 h and at r.t. for 30 min. Then the reaction mixture was neutralized with dilute HCl followed by extraction with EtOAc, washing the EtOAc layer with H2O and the organic layer was dried over anhyd Na2SO4. Evaporation of the organic solvent yielded the crude product which was purified by recrystallization or column chromatography. All products were characterized by NMR data.
11Compounds 8-14, 16 were characterized by [α] d , 1H NMR and 13C NMR data. 8: Mp 56-60 °C (lit. [14] : 59-62 °C); [α] d 20 -27.7 (c 1, MeOH). 9: Mp 82-88 °C; [α] d 20 +27.8 (c 1, MeOH). 10: Mp 50-54 °C; [α] d 20 -15.3 °C (c 1, MeOH). 11: Mp 70-80 °C; [α] d 20 -2.2 (c 1, MeOH). 12: Mp 145-149 °C (lit. [15] : 149-154 °C); [α] d 20 -19.0 (c 1, DMF) (lit.15 [α] d -20 (c 1, DMF). 13: Mp 83-88 °C (lit. [16] : 90 °C); [α] d -3.5 (c 1, MeOH). 14: Mp 65 °C (petroleum ether/ethyl acetate); [α] d 20 -62.0 (c 1, MeOH). 1H NMR (250 MHz, CDCl3): δ = 1.36 (d, J = 6.5 Hz, 3 H), 1.43 (s, 9 H), 1.99-2.30 (m, 6 H), 2.05 (s, 3 H), 2.46 (t, 6.4 Hz, 2 H), 2.90-3.10 (m, 2 H), 3.50-4.60 (m, 4 H), 6.20-6.40 (br s, 1 H), 7.40-7.60 (br s, 1 H). 13C NMR (62.9 MHz, CDCl3): δ = 15.4, 18.1, 25.0, 28.4, 30.8, 40.8, 47.5, 48.0, 54.4, 60.8, 77.2, 79.6, 155.5, 171.5, 173.8, 177.8; MALDI: m/z = 456 [M + K+]. 16: Mp 52-56 °C; [α] d 20 -39.5 (c 1, MeOH). 1H NMR (250 MHz, CDCl3): δ = 1.12 (d, J = 6.4 Hz, 3 H), 1.40 (s, 9 H), 1.90-2.2 (m, 2 H), 2.03 (s, 3 H), 2.50 (t, J = 7.4 Hz, 2 H), 3.33 (d, J = 3.0 Hz, 1 H), 4.06-4.09 (m, 1 H), 4.23-4.26 (m, 1 H), 4.39 (t, J = 5.4 Hz, 2 H), 4.56-4.65 (m, 1 H), 5.50 (d, J = 7.6 Hz, 1 H), 6.9 (br s, 1 H), 7.2-7.4 (m, 6 H). 13C NMR (62.9 MHz, CDCl3): δ = 15.2, 18.5, 28.2, 30.1, 31.2, 43.5, 52.6, 58.7, 67.2, 80.4, 127.4, 127.6, 128.6, 137.8, 156.2, 170.9. 171.2. MALDI: m/z = 462 [M + Na+].