Synthesis 2022; 54(09): 2282-2288
DOI: 10.1055/s-0037-1610792
paper

Synthesis of 5-Trifluoromethyl-Substituted (Z)-N,N-Dimethyl-N′-(pyrazin-2-yl)formimidamides from 2-Aminopyrazines, LiI/Selectfluor, FSO2CF2CO2Me and DMF under Cu Catalysis

Jiao Hu
,
Shengyu Li
,
Xiaolin Wang
,
Sheng-Cai Zheng
,

We gratefully acknowledge the National Natural Science Foundation of China (NSFC) (Grant no. 21971193) and the Fundamental Research Funds for the Central Universities for generous financial support.


Abstract

The synthesis of 5-trifluoromethyl-substituted (Z)-N,N-dimethyl-N′-(pyrazin-2-yl)formimidamides via the iodination of 2-aminopyrazines with Selectfluor/LiI followed by a domino trifluoromethylation with FSO2CF2CO2Me and a condensation with DMF in the presence of CuI is realized under mild conditions. This three-step method offers CF3-substituted (Z)-N,N-dimethyl-N′-(pyrazin-2-yl)formimidamides in yields of 55–70% and with high regioselectivities. LiI serves as an iodine source, whilst DMF functions as both a solvent and a condensation reagent. The regioselectivity of these trifluoromethylation reactions is strongly dependent upon the substituent pattern on the 2-aminopyrazines. A possible mechanism for this method is also discussed.

Supporting Information



Publikationsverlauf

Eingereicht: 17. September 2021

Angenommen nach Revision: 15. Dezember 2021

Artikel online veröffentlicht:
09. Februar 2022

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