Experiments related to the synthesis and analysis of a hydrazine library †

Substitutions under competition conditions are performed with a triprotected hydrazine reagent A as nucleophile and various halides as electrophiles and the product distribution determined by HPLC. Subsequently, after partial deprotection, stepwise substitution on the other nitrogen is studied similarly in order to define the scope of such reagents for the synthesis of libraries comprising multisubstituted hydrazines. In the course of this work a large number of partially protected hydrazine derivatives are prepared and characterized spectroscopically and chromatographically. The results indicate that n-alkyl and benzyl halides are of comparable reactivity under the conditions used, whereas others deviate too much in this respect as a result of which product mixtures severely distorted from equimolar ones are formed. In the course of this work, hydrazine libraries containing up to nine components are characterized quantitatively.