Synthesis and resolution of new paramagnetic α-amino acids

Autor: József Schindler, Tamás Kálai, Mária Balog, Elemér Fogassy, Kálmán Hideg
Rok vydání: 2008
Předmět:
Zdroj: Tetrahedron. 64:1094-1100
ISSN: 0040-4020
DOI: 10.1016/j.tet.2007.11.020
Popis: New, paramagnetic unnatural α-amino acids were synthesized by the O'Donnell method. In the new amino acids nitroxide is condensed with thiophene, benzene, and tetrahydroisoquinoline ring, or linked through a methylene, benzyl or propargyl spacer. Some of the racemic paramagnetic α-amino acid esters described earlier or in this work were resolved by fractional crystallization of diastereomeric salts. Another approach for optically active paramagnetic amino acids is the modification of S -tyrosine derivatives with Pd-catalyzed cross-coupling reactions with paramagnetic acetylene and with a paramagnetic boronic acid.
Databáze: OpenAIRE