Ethyl 5-oxo-1-phenyl-4,5-dihydro-1H-pyrazole-3-carboxylate → 3H-Pyrazol-3-one, 2,4-dihydro-2,5-diphenyl-

HRID 1289849Notes

Reaction equation

[C:1]1([N:7]2[C:11](=[O:12])[CH2:10][C:9]([C:13](OCC)=O)=[N:8]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1>NCCN1CCCC1>[C:1]1([N:7]2[C:11](=[O:12])[CH2:10][C:9]([C:13]3[CH:5]=[CH:6][CH:1]=[CH:2][CH:3]=3)=[N:8]2)[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1

Participants

Conditions

Temperature: 130 °C

Procedure

A mixture of 2,4-dihydro-2-phenyl-5-ethoxycarbonyl-3H-pyrazol-3-one (10 g; 43 mmol) and 1-(2-aminoethyl)pyrrolidine (10 ml) was heated at 130° C. under nitrogen for 2 hours and cooled. The mixture was triturated in hexane, filtered and the solid was washed with hexane to yield 15 gm of a crude product. A portion (8.6 g ) of the crude product was purified by column chromatography (silica gel, triethylamine:methanol:methylene chloride 1:9:90) to afford 5.04 g of 2,4-dihydro-2-phenyl-5-[C(O)NH(CH2)2 -1-pyrrolidinyl]-3H-pyrazol-3-one (Formula III: R1 =Ph; R2 =C(O)NH(CH2)2 -1-pyrrolidinyl; R3 =H) as a tan solid, which was further crystallized in toluene/methanol (2×) to yield a white solid, m.p. 210°-211° C.

Workup

temperaturecooled
customThe mixture was triturated in hexane
filtrationfiltered
washthe solid was washed with hexane
customto yield 15 gm of a crude product
customA portion (8.6 g ) of the crude product was purified by column chromatography (silica gel, triethylamine:methanol:methylene chloride 1:9:90)

Sources & evidence

ORD record: ord-e48a7d6ec0f14518a57105a0cc4b5cfe
Source dataset: uspto-grants-1998_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05750550

Reaction notes

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