A novel synthetic methodology for the preparation of 1,3-disubstituted pyrazoles from in situ generated nitrile imines and acetylene is reported. The reactions are performed in a simple two-chamber reactor. One part of the reactor is loaded with hydrazonoyl chloride precursors of active nitrile imine species and a base. The other part is used to generate acetylene from CaC₂ and water. Partitioning of the reactants improves the yields of desired pyrazoles up to 99% and simplifies their isolation to a simple procedure of solvent evaporation. The approach requires no complex equipment and utilizes inexpensive, safe, and easy to handle calcium carbide as a starting material. A model deuterium incorporation is carried out according to the developed methodology, producing a series of novel 4,5-dideuteropyrazoles with excellent deuterium enrichment. Theoretical calculations on reaction mechanism and characterization of possible intermediate structures were performed.

中文翻译：

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[3 + 2]-环加成原位生成的腈亚胺和乙炔，用于组装1,3-二取代吡唑并进行定量氘标记

报道了一种从原位生成的腈亚胺和乙炔制备1,3-二取代吡唑的新型合成方法。反应在简单的两室反应器中进行。反应器的一部分装有活性腈亚胺物种的酰氯前体和碱。另一部分用于从CaC ₂生成乙炔和水。反应物的分配将所需的吡唑的产率提高至高达99％，并简化了其通过简单的溶剂蒸发步骤的分离。该方法不需要复杂的设备，并利用廉价，安全且易于处理的电石作为起始原料。根据开发的方法进行模型氘掺入，产生了一系列具有优异氘富集的新型4,5-二氢杂萘并恶唑。对反应机理进行了理论计算，并对可能的中间结构进行了表征。