Ethylene Glycol → tert-butyl 4-(1-methyl-1H-pyrazol-4-yl)-3-oxopiperazine-1-carboxylate

HRID 390324Notes

Reaction equation

[O:1]=[C:2]1[NH:7][CH2:6][CH2:5][N:4]([C:8]([O:10][C:11]([CH3:14])([CH3:13])[CH3:12])=[O:9])[CH2:3]1.[CH3:15][N:16]1[CH:20]=[C:19](I)[CH:18]=[N:17]1.C(O)CO.P([O-])([O-])([O-])=O.[K+].[K+].[K+]>C(O)(C)C.[Cu](I)I>[CH3:15][N:16]1[CH:20]=[C:19]([N:7]2[CH2:6][CH2:5][N:4]([C:8]([O:10][C:11]([CH3:14])([CH3:13])[CH3:12])=[O:9])[CH2:3][C:2]2=[O:1])[CH:18]=[N:17]1

Participants

Conditions

Temperature: 100 °C

Procedure

To a solution of tert-butyl 3-oxopiperazine-1-carboxylate (0.164 g, 0.819 mmol) in 3 mL of isopropanol under an atmosphere of nitrogen was added 1-methyl-4-iodo-1H-pyrazole (0.204 g, 0.983 mmol), ethylene glycol (0.051 g, 0.82 mmol), copper iodide (0.031 g, 0.16 mmol), and potassium phosphate (0.695 g, 3.28 mmol). The reaction was heated to 100° C. for 8 h, cooled to rt, and concentrated in vacuo. The residue was dissolved in dichloromethane, washed with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 10-100% ethyl acetate in hexanes to provide tert-butyl 4-(1-methyl-1H-pyrazol-4-yl)-3-oxopiperazine-1-carboxylate that gave a mass ion (ES+) of 281.1 for [M+H]+.

Workup

temperaturecooled to rt
concentrationconcentrated in vacuo
dissolutionThe residue was dissolved in dichloromethane
washwashed with water
dry with materialdried over sodium sulfate
filtrationfiltered
concentrationconcentrated in vacuo
customThe residue was purified via silica gel chromatography
washeluting with 10-100% ethyl acetate in hexanes

Sources & evidence

ORD record: ord-27925b556c4a41b292e75d427d8d1302
Source dataset: uspto-grants-2013_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08383638B2

Reaction notes

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