Hydrochloric Acid → Benzyl 5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carboxylate

HRID 415889Notes

Reaction equation

[CH3:1][C:2]1[CH:6]=[C:5]([OH:7])[N:4]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=2)[N:3]=1.[OH-].[Ca+2].[OH-].Cl[C:18]([O:20][CH2:21][C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=1)=[O:19].Cl>O1CCOCC1>[CH3:1][C:2]1[NH:3][N:4]([C:8]2[CH:9]=[CH:10][CH:11]=[CH:12][CH:13]=2)[C:5](=[O:7])[C:6]=1[C:18]([O:20][CH2:21][C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=1)=[O:19]

Participants

Conditions

Temperature: 50 °C

Procedure

A suspension of 3-methyl-1-phenyl-1H-pyrazol-5-ol (10.0 g, 57 mmol) and calcium hydroxide (8.5 g, 115 mmol) in dry 1,4-dioxane (100 mL) was heated to 50° C. for 20 min. The suspension was chilled to 10° C. and benzyl chloroformate (8.2 ml, 57 mmol) was in dioxane (10 mL) added. The resultant was heated to 90° C. for 3 h, cooled to 25° C. and then, chilled (0° C.) 1 M HCl (200 mL) was added. The mixture was stirred at 25° C. overnight. A solid collected by filtration was washed with cold EtOH (2×25 mL) and ether (50 mL), dried at 80° C. (sand bath) exposed to air for 4 h to give the title compound (14.0 g, 79% yield) as an off-white solid. MS (ESI pos. ion) m/z: 309 (MH+). Calc'd exact mass for C18H16N2O3 308.

Workup

temperatureThe suspension was chilled to 10° C.
additionadded
temperatureThe resultant was heated to 90° C. for 3 h
temperaturecooled to 25° C.
additionwas added
filtrationA solid collected by filtration
washwas washed with cold EtOH (2×25 mL) and ether (50 mL)
customdried at 80° C. (sand bath)
waitexposed to air for 4 h

Sources & evidence

ORD record: ord-14bbab7bc4a44d4b806f8edc45b2aabf
Source dataset: uspto-grants-2012_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08088794B2

Reaction notes

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