Synthesis and resolution of new paramagnetic α-amino acids
作者:Tamás Kálai、József Schindler、Mária Balog、Elemér Fogassy、Kálmán Hideg
DOI:10.1016/j.tet.2007.11.020
日期:2008.2
New, paramagnetic unnatural α-aminoacids were synthesized by the O'Donnell method. In the new aminoacids nitroxide is condensed with thiophene, benzene, and tetrahydroisoquinoline ring, or linked through a methylene, benzyl or propargyl spacer. Some of the racemic paramagnetic α-aminoacid esters described earlier or in this work were resolved by fractional crystallization of diastereomeric salts
Starting from readily available paramagnetic five- and six-membered ketones and pyrroline aldehyde, a range of spin labeled heterocycles such as benzazoles, pyrrole, oxazole, quinoline, benzofuran, thiadiazole have been synthesized in both 'classical' and Pd-catalyzed reactions. These methods were used in the synthesis of paramagnetic ligands such as oxin and porphyrin.