Structure of <i>N</i>,<i>N</i>′-Bis(amino acids) in the Solid State and in Solution. A <sup>13</sup>C and <sup>15</sup>N CPMAS NMR Study
作者:Gema Ballano、Ana I. Jiménez、Carlos Cativiela、Rosa M. Claramunt、Dionisia Sanz、Ibon Alkorta、José Elguero
DOI:10.1021/jo801362q
日期:2008.11.7
Ala-Ala and Gly-Ala (or Ala-Gly). These compounds have been characterized by NMR both in solution and in the solidstate. They exist as zwitterions with the ammonium group proximal to the carboxylate anion. In the case of Gly-Ala, a dynamic situation is observed by CPMASNMR ((13)C and (15)N) corresponding to a doubleproton migration between two proximal tautomers.
The ruthenium tetroxide (RuO4) oxidation of the 3-substituted N,N'-diBochexahydropyridazines gave the 6-oxohexahydropyridazines in good to high yields, whereas the oxidation of the unsubstituted ones also gave the 3,6-dioxo derivatives. The 3,6-cis-disubstituted pyridazines were essentially oxidized to give the 3-hydroxypyridazines; no oxidation of the trans-derivative occurred.