Isobutylene → 3-tert-Butylamino-5-phenyl-thiophene-2-carboxylic acid methyl ester

HRID 1015635Notes

Reaction equation

[CH3:1][O:2][C:3]([C:5]1[S:6][C:7]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)=[CH:8][C:9]=1[NH2:10])=[O:4].[CH2:17]=[C:18]([CH3:20])[CH3:19]>S(=O)(=O)(O)O.O1CCOCC1.C(Cl)(Cl)Cl>[CH3:1][O:2][C:3]([C:5]1[S:6][C:7]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)=[CH:8][C:9]=1[NH:10][C:18]([CH3:20])([CH3:19])[CH3:17])=[O:4]

Participants

Conditions

Temperature: -78 °C

Procedure

Concentrated sulfuric acid (10 drop) was added to a solution of 3-Amino-5-phenyl-thiophene-2-carboxylic acid methyl ester (500 mg, 2,15 mmol) in 20 ml of dioxane/chloroforme (2:3) in a sealed tube. After cooling the solution at −78° C., put 20 ml of isobutene gaz. The sealed tube was closed and then the reaction mixture was stirred for 6 days at 60° C. The solvant was removed and then partitioned between 15 ml of sat. Na2CO3 solution and 15 ml of EtOAc. The organic layer was separated, the aqueous phase was washed twice with ethyl acetate and the combined ethyl acetate layer was dried (MgSO4), concentrated and the residue was purified by flash chromatography (5% EtOAc/Hexane) to obtain 385 mg (62%) of 3-tert-Butylamino-5-phenyl-thiophene-2-carboxylic acid methyl ester. NMR 1H (CDCl3, 400 MHz): 7.65 ppm (d, 2H, Haro); 7.44-7.38 ppm (m, 3H, Haro); 7.07 ppm (s, 1H, Haro); 3.86 ppm (s, 3H); 1.48 ppm (s, 9H).

Workup

customThe sealed tube was closed
customThe solvant was removed
custompartitioned between 15 ml of sat. Na2CO3 solution and 15 ml of EtOAc
customThe organic layer was separated
washthe aqueous phase was washed twice with ethyl acetate
dry with materialthe combined ethyl acetate layer was dried (MgSO4)
concentrationconcentrated
customthe residue was purified by flash chromatography (5% EtOAc/Hexane)

Sources & evidence

ORD record: ord-a36a346359664772944241a1570c0ce2
Source dataset: uspto-grants-2011_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07985769B2

Reaction notes

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