Abstract Specifically, 15 N-enriched L-histidines have been prepared. The labelling methodology involves introduction of labels in its precursor 1-benzyl-5-hydroxy methyl imidazole, which is converted into L-histidine via the Schöllkopf method. The procedure allows the preparation of the intermediates and finally histidine with high 15 N enrichment (99%) at each position, in 29% overall yield starting with 15 NH 4 Cl and 56% with KSC 15 ...
