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

HRID 1634097Notes

Reaction equation

[N+:1]([C:4]1[CH:9]=[CH:8][C:7]([N:10]2[C:14](Br)=[CH:13][C:12]([CH3:16])=[N:11]2)=[CH:6][CH:5]=1)([O-:3])=[O:2].C(OCC)(=O)CC(C)=O.P(Br)(Br)Br.[CH:30]([Si:33]([C:40]#[CH:41])([CH:37]([CH3:39])[CH3:38])[CH:34]([CH3:36])[CH3:35])([CH3:32])[CH3:31]>C(#N)C.C(N(CC)CC)C.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[N+:1]([C:4]1[CH:9]=[CH:8][C:7]([N:10]2[C:14]([C:41]#[C:40][Si:33]([CH:30]([CH3:32])[CH3:31])([CH:37]([CH3:39])[CH3:38])[CH:34]([CH3:36])[CH3:35])=[CH:13][C:12]([CH3:16])=[N:11]2)=[CH:6][CH:5]=1)([O-:3])=[O:2]

Participants

Conditions

Temperature: 70 °C

Procedure

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.

Workup

temperaturecooled to room temperature
filtrationThe solid was filtered off
concentrationthe filtrate was concentrated
customThe residue was purified by column chromatography on silica gel (hexane/acetate, 4:1)

Sources & evidence

ORD record: ord-6b371fe8f2ef49e7aa353d0e8740e369
Source dataset: uspto-grants-2003_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06506747B1

Reaction notes

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