p-Toluenesulfonic acid → ethyl 3-iodo-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole-4-carboxylate

Beteiligte Stoffe

Reaktionsschritte

A solution of ethyl 3-iodo-1H-pyrazole-4-carboxylate (27 g, 101.8 mmol), 3,4-DHP (25.71 g 305.6 mmol) and PTSA (1.94 g 10.18 mmol) in THF (100 mL) was heated at 60° C. for 5 h. Solvent was evaporated under vacuum and the residue redissolved in DCM (500 mL) was added. The solution was washed with sat.NaHCO3 (200 mL×2), dried, concentrated to afford crude ethyl 3-iodo-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole-4-carboxylate (35 g, yield: 98%). The crude material was used in the next synthetic step without further purification.

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