529486-21-3Relevant articles and documents
Synthesis and characterization of new chiral azolinium salts, precursors to N-heterocyclic carbenes, derived from l-proline
Thomasset, Amélia,Bouchardy, Lucie,Bournaud, Chloée,Guillot, Régis,Toffano, Martial,Vo-Thanh, Giang
, p. 242 - 250 (2014/03/21)
A short and flexible procedure for the preparation of seven chiral azolinium and five functionalized chiral azolinium salts, precursors to N-heterocyclic carbenes, derived from l-proline has been developed. Moderate to good overall yields were obtained. Some NHC dimers and thiones were isolated. X-ray crystal structure determinations of two [Rh-NHC] complexes were also reported.
Attempts toward the synthesis of the peptaibol antiamoebin by using the 'azirine/oxazolone method'
Blaser, Pia,Altherr, Werner,Linden, Anthony,Heimgartner, Heinz
, p. 920 - 941 (2013/07/28)
The two segments, 1-9 and 10-16, of the peptaibol antibiotic antiamoebin I, i.e., the nonapeptide Ac-Phe-Aib-Aib-Aib-D,L-Iva-Gly-Leu-Aib-Aib-OH (15) and the heptapeptide Z-Hyp-Gln-D,L-Iva-Hyp-Aib-Pro-Pheol (34), have been prepared as mixtures of the epimers containing D,L-Iva. All α,α-disubstituted α-amino acids were introduced by the 'azirine/oxazolone method', in which amino or peptide acids are coupled with the corresponding 2H-azirin-3-amines, followed by selective hydrolysis of the terminal amide bond. The amino acids Hyp and Gln were introduced as Z-protected4) (2S,4R)-4-(tert-butoxy) proline (19) and methyl N-[bis(4-methoxyphenyl)methyl]glutamine (26). Coupling of peptide segments was achieved via the 'mixed anhydride' method, the DCC/HOBt or TBTU/HOBt strategy. The crystal structure of the segment 6-9 was determined by X-ray crystallography and displayed the presence of a β-turn conformation. Copyright
Chemical synthesis of 15N-labeled analogues of zervamicin IIB
Rimawi,Ogrel,Raap,Shvets
, p. 725 - 733 (2007/10/03)
Analogues of 16-membered peptide antibiotic zervamicin IIB with the Gln3 and Gln11 residues 15N-labeled at the Cα-atoms were synthesized by coupling the antibiotic segments (1-4), (5-9), and (10-16). In turn, these were prepared by a stepwise chain elongation in solution starting from their C-termini using benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (BOP) as an activating agent. The sterically hindered 2-aminoisobutyric acid was introduced by the BOP-dimethylaminopyridine system with the preactivation of the carboxyl component. The segment condensation was performed with the use of the 6-trifluoromethylbenzotriazol-1-yloxy-tris(pyrrolidino)phosphonium hexafluorophosphate activating reagent. The homogeneity of the resulting zervamicin analogues was confirmed by HPLC, and their structures were proved by NMR spectroscopy and FAB mass spectrometry.