Trifluoromethyl-modified dipeptides by ZrCl4-promoted aza-Henry reactions.
Amino Acids 2014;
46:1961-70. [PMID:
24802246 DOI:
10.1007/s00726-014-1749-4]
[Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 04/10/2014] [Indexed: 10/25/2022]
Abstract
Chiral (R)-1-phenylethylamine was successfully employed in a tandem aza-Henry addition-reduction reaction to give chiral β-nitro α-trifluoromethyl amines. A subsequent coupling reaction with N-Boc-protected amino acids leads to obtain optically pure CF3-modified dipeptides carrying two different N-protecting groups. These peptidomimetic units are characterized by the presence of the [CH(CF3)NH] group as mimetic of the natural [CONH] peptidic bond and can be used for the synthesis of more complex CF3-modified peptides after selective deprotection of one of the two amine functions. 2D NMR spectral analyses were employed to determine the absolute configurations of all newly synthesized chiral compounds.
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