N-Methylethylenediamine → 1-Methyl-3-(4-nitrophenyl)-5,6-dihydropyrazin-2(1H)-one

HRID 1772078Notes

Reaction equation

[N+:1]([C:4]1[CH:9]=[CH:8][C:7]([CH2:10][C:11](=[O:17])C(OCC)=O)=[CH:6][CH:5]=1)([O-:3])=[O:2].[CH3:18][NH:19][CH2:20][CH2:21][NH2:22]>CO>[CH3:18][N:19]1[CH2:20][CH2:21][N:22]=[C:10]([C:7]2[CH:6]=[CH:5][C:4]([N+:1]([O-:3])=[O:2])=[CH:9][CH:8]=2)[C:11]1=[O:17]

Participants

Conditions

Temperature: 0 °C

Procedure

A 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer was purged with nitrogen, charged with ethyl 4-nitrophenylpyruvate (5.00 g, 22.4 mmol) and anhydrous methanol (112 mL). The resulting solution was cooled to 0° C. with an ice bath, and N-methylethylenediamine (1.66 g, 22.4 mmol) was added dropwise. After addition was complete, the bath was removed and the reaction was stirred at room temperature for 18 h. After this time the reaction was concentrated under reduced pressure. The residue was purified by column chromatography to afford 1-methyl-3-(4-nitrophenyl)-5,6-dihydropyrazin-2(1H)-one (102h) in 20% yield (1.02 g) as a yellow solid: mp 191-192° C.; 1H NMR (300 MHz, DMSO-d6) δ 8.26 (d, 2H, J=6.9 Hz), 8.05 (d, 2H, J=7.2 Hz), 3.94 (t, 2H, J=6.3 Hz), 3.55 (t, 2H, J=6.3 Hz), 3.02 (s, 3H); MS (ESI+) m/z 234.1 (M+H).

Workup

customA 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer
customwas purged with nitrogen
additionAfter addition
customthe bath was removed
concentrationAfter this time the reaction was concentrated under reduced pressure
customThe residue was purified by column chromatography

Sources & evidence

ORD record: ord-78f75b24a5624e278b4817b85c3d926a
Source dataset: uspto-grants-2016_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09249123B2

Reaction notes

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