Phosphorus Pentoxide-Methanesulfonic Acid → 5-imidazol-1-yl-1H-indole-2-carboxylic acid ethyl ester

HRID 74461Notes

Reaction equation

[CH2:1]([O:3][C:4](=[O:19])/[C:5](=[N:7]/[C:8]1[CH:13]=[CH:12][C:11]([N:14]2[CH:18]=[CH:17][N:16]=[CH:15]2)=[CH:10][CH:9]=1)/[CH3:6])[CH3:2].CS(O)(=O)=O.O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O>P([O-])([O-])([O-])=O.[K+].[K+].[K+]>[CH2:1]([O:3][C:4]([C:5]1[NH:7][C:8]2[C:9]([CH:6]=1)=[CH:10][C:11]([N:14]1[CH:18]=[CH:17][N:16]=[CH:15]1)=[CH:12][CH:13]=2)=[O:19])[CH3:2]

Participants

Conditions

Temperature: 100 °C

Procedure

2-[(E)-4-Imidazol-1-yl-phenylimino]-propionic acid ethyl ester (842 mg) was added to an Eaton's reagent (4 ml), and this was stirred at 100° C. for one hour. After adjusting the pH of the reaction mixture to 11 using an aqueous solution (about 10 ml) of 20% potassium phosphate, the mixture was extracted with ethyl acetate (30 ml). The organic layer was washed with an aqueous solution saturated with sodium chloride (20 ml), and the organic layer was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (dichloromethane/methanol). Thus, 5-imidazol-1-yl-1H-indole-2-carboxylic acid ethyl ester was obtained as a yellow amorphous material (370 mg, 47%).

Workup

extractionthe mixture was extracted with ethyl acetate (30 ml)
washThe organic layer was washed with an aqueous solution saturated with sodium chloride (20 ml)
concentrationthe organic layer was concentrated under reduced pressure
customThe resulting residue was purified by silica gel column chromatography (dichloromethane/methanol)

Sources & evidence

ORD record: ord-fb7583543c5e4ae7b1af14d67f34695d
Source dataset: uspto-grants-2014_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08829199B2

Reaction notes

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