Sodium Bicarbonate → 2-Oxo-1-(1-benzylpiperidin-4-yl)-2,3-dihydro-1H-imidazo[4,5-b]pyrazine
Reaction equation
[CH2:1]([N:8]1[CH2:13][CH2:12][CH:11]([NH:14][C:15]2[C:16](C(NN)=O)=[N:17][CH:18]=[CH:19][N:20]=2)[CH2:10][CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[N:25]([O-])=O.[Na+].[C:29](=[O:32])(O)[O-].[Na+]>Cl.O>[O:32]=[C:29]1[N:14]([CH:11]2[CH2:10][CH2:9][N:8]([CH2:1][C:2]3[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=3)[CH2:13][CH2:12]2)[C:15]2=[N:20][CH:19]=[CH:18][N:17]=[C:16]2[NH:25]1Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- 180 °C
Procedure
3-[(1-Benzylpiperidin-4-yl)amino]pyrazine-2-carbohydrazide (3.0 g, 9.2 mmol) was dissolved in 1N HCl (20 mL) and water (40 mL), and cooled to 0° C. To this was added aqueous sodium nitrite (0.8 g, 11.6 mmol) in water (5 mL). After 0.5 h sodium bicarbonate was added and the basic solution extracted with chloroform (5×50 mL), which was dried over magnesium sulfate. The crude acyl azide was dissolved in methoxyethanol (20 mL) and heated at 180° C. for 3 h. The progress of the reaction was monitored by thin layer chromatography (10% methanol in chloroform). The reaction was cooled and concentrated, and the crude product purified by preparative thin layer chromatography (silica gel, 75:25 tetrahydrofuran:hexane) to give the title compound (1.7 g). MS 310 (M+1).
Workup
- extractionthe basic solution extracted with chloroform (5×50 mL), which
- dry with materialwas dried over magnesium sulfate
- dissolutionThe crude acyl azide was dissolved in methoxyethanol (20 mL)
- temperatureThe reaction was cooled
- concentrationconcentrated
- customthe crude product purified by preparative thin layer chromatography (silica gel, 75:25 tetrahydrofuran:hexane)
Sources & evidence
- ORD record
- ord-7e0867d914d24b5ab4a2017982b7a8a3
- Source dataset
- uspto-grants-2007_06
- Patent number
- US07235545B2
Reaction notes
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