Ethyl Acetoacetate → 1-(4'-Nitrophenyl)-5-(2-triisopropylsilylethynyl)-3-methylpyrazole

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-(4′-nitrophenyl)-5-bromo-3-methylpyrazole (prepared as described for Example 19 except using ethyl acetoacetate instead of ethyl trifluoroacetoacetate and using PBr3 in acetonitrile and refluxing for 72 hr for the halogenation step) (100 mg, 0.35 mmol) in triethylamine (5 mL) was added Pd(PPh3)4 (20 mg, 0.017 mmol) and CuBrSMe2 (8 mg, 0.036 mmol), followed by triisopropylsilylacetylene (72 mg, 0.39 mmol). The mixture was heated to 70° C. for 1 hour and cooled to room temperature. The solid was filtered off and the filtrate was concentrated. The residue was purified by column chromatography on silica gel (hexane/acetate, 4:1) to give the title compound (127 mg, 95%). mp: 71-73° C.

Provenance & Evidence