1,3-Bis(diphenylphosphino)propane → 6-(4-tert-butyl-phenyl)-5H-pyrazolo[1,5-a]pyrazin-4-one

HRID 2272958Notes

Reaction equation

[C:1]([C:5]1[CH:10]=[CH:9][C:8]([C:11]2[NH:12][C:13](=[O:22])[C:14]3[N:15]([N:17]=[C:18](C=O)[CH:19]=3)[CH:16]=2)=[CH:7][CH:6]=1)([CH3:4])([CH3:3])[CH3:2].C1(P(C2C=CC=CC=2)CCCP(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>O.O.O.[Rh](Cl)(Cl)Cl>[C:1]([C:5]1[CH:6]=[CH:7][C:8]([C:11]2[NH:12][C:13](=[O:22])[C:14]3[N:15]([N:17]=[CH:18][CH:19]=3)[CH:16]=2)=[CH:9][CH:10]=1)([CH3:4])([CH3:2])[CH3:3]

Participants

Conditions

Temperature: 160 °C

Procedure

140 mg (0.473 mmol) 6-(4-tert-butyl-phenyl)-4-oxo-4,5-dihydro-pyrazolo[1,5-a]pyrazine-2-carbaldehyde are dissolved in 1 ml diethyleneglycoldimethylether. 12 mg (0.028 mmol) 3-diphenylphosphanylpropyl(diphenyl)phosphane and 3.7 mg (0.014 mmol) rhodium(III)-chloride trihydrate are added. The reaction mixture is stirred for 42 hours at 160° C. The mixture is cooled to room temperature and partitioned between dichloromethane and water. The organic phase is dried over sodium sulfate and evaporated. The residue is chromatographed on a silica gel column with cyclohexane/ethyl acetate as eluent to give 6-(4-tert-butyl-phenyl)-5H-pyrazolo[1,5-a]pyrazin-4-one (“A15”) as colourless crystals; HPLC/MS: 1.88 (C), [M+H] 268.

Workup

temperatureThe mixture is cooled to room temperature
custompartitioned between dichloromethane and water
dry with materialThe organic phase is dried over sodium sulfate
customevaporated
customThe residue is chromatographed on a silica gel column with cyclohexane/ethyl acetate as eluent

Sources & evidence

ORD record: ord-ca15a3546ead4bbe849d1fd38de7d3ad
Source dataset: uspto-grants-2015_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09120805B2

Reaction notes

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