Solution-Phase and Solid-Phase Synthesis of 1-Pyrazol-3-ylbenzimidazoles

Abstract

The facile solution and solid-phase synthesis of 1-pyrazol-3-ylbenzimidazoles from 4-fluoro-3-nitrobenzoate derivatives and 5(3)-amino-3(5)-subtituted-1H-pyrazoles is reported. The key step is the unexpected nucleophilic aromatic displacement of the activated fluorine by the exocyclic amino group of the pyrazole ring leading to 4-pyrazolylamino-3-nitrobenzoate derivatives, which are easily converted into the corresponding 1-pyrazol-3-ylbenzimidazoles in very high isolated yield. These novel methodologies would be very useful for the generation of libraries of diverse 1-heteroaryl derivatives of benzimidazoles.

Key words

solid-phase synthesis - combinatorial chemistry - heterocycles - benzimidazoles - pyrazoles

References

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