The reaction of hydrazines with α,β-unsaturated carbonyl compounds to afford 2-pyrazolines was studied using a dissymmetric chalcone (phenyl/p-tolyl) and three hydrazines, hydrazine itself, phenylhydrazine and thiosemicarbazide. Several products were identified, and some reaction paths established thanks to the evolution of ¹H and ¹³C NMR spectra with time. Theoretical calculations on energies and chemical shifts were of paramount importance to ascertain the structure of some products. For important steps, the transition states were calculated while IRCs proved necessary to find some unexpected intermediates.

中文翻译：

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肼与 α,β-不饱和羰基化合物反应生成腙和 2-吡唑啉（4,5-二氢-1H-吡唑）的机理：实验和理论结果

使用不对称查耳酮（苯基/对甲苯基）和三种肼（肼本身、苯肼和氨基硫脲）研究了肼与 α,β-不饱和羰基化合物反应生成 2-吡唑啉。由于¹ H 和¹³ C NMR 光谱随时间的演变，确定了几种产物，并建立了一些反应路径。能量和化学位移的理论计算对于确定某些产品的结构至关重要。对于重要的步骤，计算了过渡态，而 IRC 证明需要找到一些意想不到的中间体。