Treatment of N-propargyl-N′-tosylhydrazines with molecular iodine (I₂) in the presence of NaHCO₃ under warming conditions gave efficiently the corresponding 5-substituted 4-iodo-1-tosylpyrazoles in good to moderate yields. In addition, the same reaction in the presence of acetic acid generated the corresponding 5-aryl-4-iodopyrazoles in moderate yields. The reactions are simple and efficient transition-metal-free methods for the preparation of 5-substituted 4-iodo­pyrazole unit.

中文翻译：

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通过碘环化从 N-炔丙基-N'-甲苯磺酰肼轻松一锅法制备 5-取代的 4-Iodo-1-tosylpyrazoles

在升温条件下，在 NaHCO ₃存在下用分子碘 (I ₂ )处理N-炔丙基-N'-甲苯磺酰基肼，以良好至中等的产率有效地产生相应的 5-取代的 4-碘-1-甲苯磺酰基吡唑。此外，在乙酸存在下的相同反应以中等收率产生相应的 5-aryl-4-iodopyrazoles。该反应是制备5-取代4-碘吡唑单元的简单有效的无过渡金属方法。