Ethyl 4,4,4-trifluoroacetoacetate → 4-Hydroxy-1-methyl-3-phenyl-4-trifluoromethyl-1,4,5,7-tetrahydro-pyrazolo[3,4-b]pyridin-6-one

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Reaction Steps

2-Methyl-5-phenyl-2H-pyrazol-3-ylamine (vii) (100 mg, 0.58 mmol) was dissolved in glacial acetic acid (1 mL), ethyl-4,4,4-trifluoracetoacetate (0.13 mL, 0.85 mmol) was added at RT and stirring was continued for 2.5 h at 120° C. The mixture was evaporated to dryness and the isomeric mixture was directly purified by preparative HPLC (Agilent 1100 Series, Chromolith prep RP-18e, 100-25). A colorless solid (29 mg, 0.09 mmol, 16%) was obtained, characterized as compound (viii).

Provenance & Evidence