Carbamimidic acid, methyl ester, sulfate (1:1) → HCID 178498445, compound

HRID 1387369Notes

Reaction equation

[N+:1]([C:4]1[CH:9]=[CH:8][C:7]([CH:10]=[C:11]([C:16](=O)[CH3:17])[C:12]([O:14][CH3:15])=[O:13])=[CH:6][CH:5]=1)([O-:3])=[O:2].S(O)(O)(=O)=O.[CH3:24][O:25][C:26](=[NH:28])[NH2:27].CC([O-])=O.[Na+]>CN(C=O)C>[CH3:15][O:14][C:12]([C:11]1[CH:10]([C:7]2[CH:8]=[CH:9][C:4]([N+:1]([O-:3])=[O:2])=[CH:5][CH:6]=2)[NH:28][C:26]([O:25][CH3:24])=[N:27][C:16]=1[CH3:17])=[O:13]

Participants

Conditions

Temperature: 72.5 °C

Procedure

A mixture of methyl 2-{(4-nitrophen-yl)methylene}-3-oxobutyrate (12.46 g, 0.05 mol), O-methylisourea hydrogen sulfate (10.32 g, 0.06 mol), and NaOAc (9.84 g, 0.06 mol) in DMF (50 mL) was stirred and heated at 70-75° C. for 4 hours. The mixture was cooled and poured into ice-water (300 mL). The precipitate formed was filtered, washed with water, and dried. The crude product was purified by flash column chromatography on silica gel using 10% through 30% EtOAc in hexane as the gradient eluent (9.8 g, 64%). The 1H-NMR analysis of the product showed it to be a 19:1 mixture of the amine/imine tautomers which was used as such in the next step. 1H-NMR (CDCl3): δ 2.32, 2.38 (2 s, 3H), 3.59, 3.70 (2 s, 3H), 3.70, 3.85 (2 s, 3H), 5.40, 5.66 (s, d, J=3 Hz, 1H), 5.50, 6.08 (s, d, J=3 Hz, 1H), 7.43, 7.45 (2 d, J=9 Hz, 2H), 8.10, 8.11 (2 d, J=9 Hz, 2H).

Workup

temperatureThe mixture was cooled
customThe precipitate formed
filtrationwas filtered
washwashed with water
customdried
customThe crude product was purified by flash column chromatography on silica gel using 10% through 30% EtOAc in hexane as the gradient eluent (9.8 g, 64%)
additiona 19:1 mixture of the amine/imine tautomers which

Sources & evidence

ORD record: ord-ebf5408d8a9c4e0f85e3140b45c5da75
Source dataset: uspto-grants-2001_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06268369B1

Reaction notes

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