Experiments related to the synthesis and analysis of a hydrazine library

Substitutions under competition conditions are performed with a triprotecte d hydrazine reagent A as nucleophile and various halides as electrophiles a nd the product distribution determined by HPLC. Subsequently, after partial deprotection, stepwise substitution on the other nitrogen is studied simil arly in order to define the scope of such reagents for the synthesis of lib raries 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 indic ate that n-alkyl and benzyl halides are of comparable reactivity under the conditions used, whereas others deviate too much in this respect as a resul t of which product mixtures severely distorted from equimolar ones are form ed. In the course of this work, hydrazine libraries containing up to nine c omponents are characterized quantitatively.