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Synthesis 2022; 54(13): 3114-3124
DOI: 10.1055/s-0041-1737395
DOI: 10.1055/s-0041-1737395
paper
Facile One-Pot Preparation of 5-Substituted 4-Iodo-1-tosylpyrazoles from N-Propargyl-N′-tosylhydrazines through Iodocyclization
This work was supported by JSPS KAKENHI Grant Number JP18K05118 in Japan.


Abstract
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.
Key words
4-iodopyrazole - molecular iodine - iodocyclization - N-propargyl-N′-tosylhydrazine - transition-metal-freeSupporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/s-0041-1737395. Included are copies of 1H NMR and 13C NMR spectra of all starting N-arylpropargyl-N′-tosylhydrazines 1 and pyrazoles 2, 3, and 3A–6A.
- Supporting Information
Publikationsverlauf
Eingereicht: 18. Januar 2022
Angenommen nach Revision: 15. Februar 2022
Artikel online veröffentlicht:
28. März 2022
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