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-h ydrazine as a stable crystalline solid. Although its nucleophilicity is con siderably suppressed in comparison with that of non- or monoacylated hydraz ines, it reacted under various conditions with a representative set of keto nes to give the corresponding hydrazones in high yields. The aliphatic hydr azones 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 c onditions. The new reagent and an alkylated derivative retained satisfactor y reactivity towards activated isocyanates to provide acyl ureas. Some char acteristic features of the NMR- and IR-spectra of these novel compounds are briefly discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.