Reactions of polyfunctional amino acids with N,N'-carbonyldiimidazole in aqueous solution--oligopeptide formation.
1. Serine reacts with N,N'-carbonyldiimidazole in aqueous solution at 0 degrees C to yield Nalpha-[imidazolyl-(1)-carbonyl]-L-serine. This compound slowly transforms to L-2-oxo-oxazolidine-5-carboxylic acid. We found that L-2-oxo-oxazolidine-5-carboxylic acid was stable to hydrolysis under a variety of conditions and did not oligomerize to yield peptides. Threonine was found to react in an analogous manner with N,N'-carbonyldiimidazole, yielding Nalpha-[imidazolyl-(1)-carbonyl]-L-threonine and L-(+)-trans-5-methyl-2-oxo-oxazolidine-5-carboxylic acid. 2. Histidine reacts with N,N'-carbonyldimidazole in aqueous solution at 0 degrees C to yield a variety of histidine-containing intermidiates. These slowly transform to give 7-carboxy-imidazole-[1,5cotetrahydropyrimidin-5-one in up to 90% yield. 3. The polymerization of 7-carboxy-imidazo-[1,5c]-tetrahydropyrimidin-5-one in imidazole buffer at 30 degrees gives excellent yields of oligohistidines.
D000596:Amino Acids; D004151:Dipeptides; D004590:Electrophoresis, Paper; D006639:Histidine; D007093:Imidazoles; D007202:Indicators and Reagents; D008722:Methods; D009842:Oligopeptides / Q000138:chemical synthesis*; D012694:Serine; D013912:Threonine
D000596:Amino Acids; D004151:Dipeptides; D007093:Imidazoles; D007202:Indicators and Reagents; D009842:Oligopeptides; D013912:Threonine; D012694:Serine; D006639:Histidine