128422-11-7Relevant academic research and scientific papers
New optically active 2H-azirin-3-amines as synthons for enantiomerically pure 2,2-disubstituted glycines
Brun, Kathrin A.,Linden, Anthony,Heimgartner, Heinz
, p. 1756 - 1777 (2007/10/03)
The synthesis of novel 2,2-disubstituted 2H-azirin-3-amines with a chiral amino group is described. Chromatographic separation of the diastereoisomer mixture yielded the pure diastereoisomers (1′R,2R)-4a-e and (1′R,2S)-4a-e (Scheme 1, Table 1), which are
Optically active 3-amino-2H-azirines as synthons for enantiomerically pure α,α-disubstituted α-amino acids: Syntheses of isovaline synthons and a segment of Trichotoxin A-50
Bucher, Christoph B.,Heimgartner, Heinz
, p. 1903 - 1915 (2007/10/03)
The synthesis of a novel 3-amino-2-methyl-2-[2-(phenylsulfonyl)ethyl]-2H-azirine derivative 12 with a chiral substituent at the amino group is described. Chromatographic separation of the diastereoisomer mixture gave pure diastereoisomers which, after an electrochemical cleavage of the phenylsulfonyl group, yielded the (S)- and (R)-isovalin (Iva) synthons 13a and 13b, respectively. The absolute configuration of the precursor molecule 12b was established by X-ray crystallography. The Iva synthons were successfully used in the synthesis of the C-terminal pentapeptide Z-Leu-Aib-(R)-Iva-Gln-Valol of the peptaibole Trichotoxin A-50 and its epimer.
PyBOP and PyBroP: Two reagents for the difficult coupling of the α,α-dialkyl amino acid, Aib
Frerot, Eric,Coste, Jacques,Pantaloni, Antoine,Dufour, Marie-Noelle,Jouin, Patrick
, p. 259 - 270 (2007/10/02)
The difficult coupling of α-aminoisobutyric acid (Aib) was carried out using PyBOP and PyBroP in a comparative study with BOP and BroP. These reagents gave good results under simple conditions (one pot, r.t., 1h). Coded amino acids could be coupled with Aib using PyBOP under standard conditions of peptide synthesis without racemization whereas the coupling of two Aib residues required PyBroP/DMAP. A fragment containing an Aib C-terminal could be coupled without epimerization of the penultimate residue.
