227015-10-3Relevant academic research and scientific papers
An unprecedented rearrangement of a 1,1-diprotected hydrazine derivative. Structure revision of a catalyst-containing by-product
Ragnarsson, Ulf,Grehn, Leif,Pehk, T?nis
supporting information, p. 7019 - 7022 (2015/02/02)
Treatment of 1-Boc-1-tosyl-hydrazine with 1,1,3,3-tetramethylguanidine (TMG) gave rise to two products, one containing and the other not containing TMG. The latter was identified as 1-Boc-2-tosyl-hydrazine. This rearrangement provided useful insight into the nature of the first product that had previously been isolated and assigned an incorrect tentative structure. To rationalize the results a plausible mechanism via a common intermediate, involving TMG as a nucleophilic catalyst is proposed. A simpler procedure for the preparation of the starting material is also presented.
1-Tert-butoxycarbonyl-1-tosyl-hydrazine as reagent for the synthesis of substituted hydrazines with a secondary alkyl group
Grehn, Leif,Ragnarsson, Ulf
, p. 4843 - 4852 (2007/10/03)
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 MR- and IR-spectra of these novel compounds are briefly discussed.
