3-Cyclobutene-1,2-dione, 3,4-dimethoxy- → HCID 89534509, compound

HRID 1528208Notes

Reaction equation

[NH2:1][C:2]1[C:3]([F:20])=[C:4]([C:16]([F:19])=[CH:17][CH:18]=1)[C:5]([N:7]1[CH2:11][CH2:10][CH2:9][C@H:8]1[C:12]([O:14][CH3:15])=[O:13])=[O:6].[CH3:21][O:22][C:23]1[C:24](=O)[C:25](=[O:29])[C:26]=1[O:27]C>CO>[F:20][C:3]1[C:2]([NH:1][C:24]2[C:25](=[O:29])[C:26](=[O:27])[C:23]=2[O:22][CH3:21])=[CH:18][CH:17]=[C:16]([F:19])[C:4]=1[C:5]([N:7]1[CH2:11][CH2:10][CH2:9][C@H:8]1[C:12]([O:14][CH3:15])=[O:13])=[O:6]

Participants

Conditions

Temperature: 60 °C

Procedure

A mixture of methyl (S)-1-(3-amino-2,6-difluorobenzoyl)pyrrolidine-2-carboxylate (prepared above) and 4.20 g (29.55 mmol) of 3,4-dimethoxycyclobut-3-ene-1,2-dione in solution in 50 ml of methanol was heated at 60° C. for one hour and then stirred at ambient temperature for 4 hours. The reaction medium was concentrated and the residue (6.29 g) was chromatographed on silica gel (300 g prepacked column, eluted with heptane/ethyl acetate, from 70% to 100% of ethyl acetate). 2.30 g of methyl (S)-1-[2,6-difluoro-3-(2-methoxy-3,4-dioxocyclobut-1-enylamino)benzoyl]-pyrrolidine-2-carboxylate were obtained. Yield=79%.

Workup

concentrationThe reaction medium was concentrated
customthe residue (6.29 g) was chromatographed on silica gel (300 g prepacked column, eluted with heptane/ethyl acetate, from 70% to 100% of ethyl acetate)

Sources & evidence

ORD record: ord-d87dfea5311d42ab9c95ba4273f2a7d7
Source dataset: uspto-grants-2015_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09090596B2

Reaction notes

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