Abstract
Products containing Boc- or Tr-protected amines were caught directly out of reaction mixtures by simultaneous cleavage of the protecting group. By releasing the products with ammonia the corresponding free amines were obtained in high yields and purities. The broadly applicable method of simultaneous deprotection and purification based on ionic resin capture was applied for Grignard and Mitsunobu reactions as well as amide formations and show a high potential for multiparallel synthesis.
Key words
ion exchange - facile purification - Boc deprotection - Tr deprotection - combinatorial chemistry
References
1a
Eames J.
Watkinson M.
Eur. J. Org. Chem.
2001,
1213
1b
Parlow JJ.
Devraj RV.
South MS.
Curr. Opin. Chem.
1999,
3:
320
2
Siegel MG.
Hahn PJ.
Dressman BA.
Fritz JE.
Grunwell JR.
Kaldor SW.
Tetrahedron Lett.
1997,
38:
3357
3a
Ley SV.
Baxendale IR.
Brusotti G.
Caldarelli M.
Massi A.
Nesi M.
Farmaco
2002,
57:
321
3b
Van den Eynde I.
Van Rompaey K.
Lazarro F.
Tourwé D.
J. Comb. Chem.
2004,
6:
468
4
Bhattacharyya S.
Curr. Opin. Drug Discovery Dev.
2004,
7:
752
5a
Thompson LA.
Curr. Opin. Chem. Biol.
2000,
4:
324
5b
Rademann J. In
Highlights in Bioorganic Chemistry. Polymer Supported Synthetic Methods - Solid-Phase Synthesis (SPS) and Polymer-Assisted Solution-Phase (PASP) Synthesis
Wiley-VCH;
Weinheim:
2004.
p.290
5c
Dolle RE.
J. Comb. Chem.
2005,
7:
739
6a
Gray CJ.
Khoujah AM.
Tetrahedron Lett.
1969,
31:
2647
6b
Seto H.
Mander LN.
Synth. Commun.
1992,
22:
2832
6c
Liu Y.-S.
Zhao C.
Bergbreiter DE.
Romo D.
J. Org. Chem.
1998,
63:
3471
6d
Baxendale IR.
Ernst M.
Krahnert W.-R.
Ley SV.
Synlett
2002,
1641
6e
Mukade T.
Dragoli DR.
Ellman JA.
J. Comb. Chem.
2003,
5:
590
7 Bondesil SCX (purchased from Varian Deutschland GmbH, Darmstadt, Germany) was used since this silica-based scavenger has a high density that facilitates the settling after shaking in multiparallel fashion. The solvent can be removed therefore faster and more easily than with an organic-polymer-based ion-exchange resin.
8 Grignard reagents were purchased from Rieke Metals Inc. (NE, USA; 2a) or Fluka Chemie GmbH (CH; 2b, 2c, 2c, 2d) as solutions in THF. Compound 1 and the alcohols 5b and 5d were supplied by ABCR GmbH & Co KG (Karlsruhe, Germany). All other reagents, Dowex 2X8-200 and solvents were purchased from Fluka Chemie GmbH (Buchs-CH).
9
Magdolen P.
Vasella A.
Helv. Chim. Acta
2005,
88:
2454