A convenient method has been developed for the synthesis of 2,4-dihydro-6H-thieno[3,4-c]pyrazol-6-ones by means of an intramolecular cyclization of 4-sulfanylmethylpyrazole-3-carboxylic acids. The latter were prepared from ethyl 4-formylpyrazole-3-carboxylates via the intermediate 4-hydroxy-methyl-, 4-chloromethyl-, and 4-thioureidomethyl derivatives.

This method allows for the synthesis of 2,4-dihydro-6H-thieno[3,4-c]pyrazol-6-ones by intramolecular cyclization of 4-sulfanylmethylpyrazole-3-carboxylic acids, with potential applications in organic synthesis.

Paper

Polyfunctional pyrazoles. 7*. Ethyl 1-aryl-4-formylpyrazole-3-carboxylates in the synthesis of 2-aryl-2,4-dihydro-6H-thieno-[3,4-c]pyrazol-6-ones

References

Citations