A practical and efficient method for N-amination of piperazine via a nitrosoamine, suitable for a large scale synthesis, is described. This method involved the temporary transformation of an in situ prepared aminopiperazine to a hydrazone, allowing efficient separation of zinc salt byproducts from the system. Acylation and deprotection with hydroxylamine directly afforded FR062732 in satisfactory quality for pharmacological evaluation. These methods solved ...
