1-tert-butoxycarbonyl-1-tosyl-hydrazine as reagent for the synthesis of substituted hydrazines with a secondary alkyl group

Catalytic hydrogenolysis of 1-Boc-1-Ts-2-Z-hydrazine furnished 1-Boc-1-Ts-hydrazine as a stable crystalline solid. Although its nucleophilicity is considerably suppressed in comparison with that of non- or monoacylated hydrazines, it reacted under various conditions with a representative set of ketones to give the corresponding hydrazones in high yields. The aliphatic hydrazones were readily reduced to hydrazines with NaBH4, whereas the aromatic analogues for smooth reduction required the more powerful NaBH3CN. With one exception all the new compounds were crystalline and stable under normal conditions. The new reagent and an alkylated derivative retained satisfactory reactivity towards activated isocyanates to provide acyl ureas. Some characteristic features of the NMR- and IR-spectra of these novel compounds are briefly discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.