Title:Synthesis of TFA-protected α-Amino Acid Chloride via a Vilsmeier Reagent for Friedel–Crafts Acylation
Volume: 17
Issue: 8
Author(s): Zetryana Puteri Tachrim, Kazuhiro Oida, Fumina Ohashi, Natsumi Kurokawa, Lei Wang, Takeyuki Suzuki and Makoto Hashimoto *
Affiliation:
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 0608589,Japan
Keywords:
Vilsmeier reagent, α-Amino acid chloride, Friedel-Crafts acylation, α-amino acid, α-amino arylketone, racemization.
Abstract: α-Amino acid chlorides are reactive coupling agents in amide (peptide) formation. The
Vilsmeier reagent ((chloromethylene)dimethylammonium chloride) offers a convenient way to prepare
α-amino acid chlorides for peptide synthesis. Its use with N-trifluoracetyl (TFA)-protected isoleucine
and allo-isoleucine is described. The 1H-NMR of the α-proton signal offers a convenient way to monitor
the chirality retention in the acid chloride forming reaction and subsequent Friedel-Crafts acylation
of arenes which result in α-amino acid aryl-ketone with no loss of chirality.