Synthesis of 2H-1,2,3-triazole-4-carboxylic acids via Ru(II)-catalyzed rearrangement of 4-hydrazonoisoxazol-5-ones

An atom-economy, two-step synthesis of 2H-1,2,3-triazole-4-carboxylic acids from 3-arylisoxazol-5(4H)-ones and arenediazonium tetrafluoroborates is described. The formation of the 1,2,3-triazole ring is achieved by the [Ru(p-cymene)Cl2]2-catalyzed rearrangement of 4-hydrazonoisoxazol-5-ones which are resulted from the diazo coupling. The advantages of the method include the available starting com-pounds and the ability to purify target acids without the use of chromatography.& COPY; 2023 Elsevier Ltd. All rights reserved.

Automated summary

This article describes an atom-economy, two-step synthesis method for 2H-1,2,3-triazole-4-carboxylic acids from 3-arylisoxazol-5(4H)-ones and arenediazonium tetrafluoroborates. The formation of the 1,2,3-triazole ring is achieved through the [Ru(p-cymene)Cl2]-catalyzed rearrangement of 4-hydrazonoisoxazol-5-ones, which are formed from the diazo coupling. The advantages of this method include the availability of starting compounds and the ability to purify target acids without the use of chromatography.