Acetic Anhydride → 1-[1-(4-Ethoxyphenyl)-2,5-dimethyl-1H-pyrrol-3-yl]ethan-1-one

HRID 2375369Notes

Reaction equation

[C:1](OC(=O)C)(=[O:3])[CH3:2].I.[CH3:9][C:10]1[N:11]([C:16]2[CH:21]=[CH:20][C:19]([O:22][CH2:23][CH3:24])=[CH:18][CH:17]=2)[C:12]([CH3:15])=[CH:13][CH:14]=1>[OH-].[Na+]>[C:1]([C:13]1[CH:14]=[C:10]([CH3:9])[N:11]([C:16]2[CH:21]=[CH:20][C:19]([O:22][CH2:23][CH3:24])=[CH:18][CH:17]=2)[C:12]=1[CH3:15])(=[O:3])[CH3:2]

Participants

Conditions

Temperature: 100 °C

Procedure

Acetic anhydride (8.5 mL, 89 mmol) and hydriodic acid (0.48 mL, 6.3 mmol) were added to 2,5-dimethyl-1-(4-ethoxyphenyl)pyrrole (8.0 g, 37 mmol) under nitrogen and the resulting mixture maintained at 100° C. overnight. After cooling to rt, the mixture was diluted with 1N NaOH (200 mL), extracted with EtOAc (2×200 mL), and the combined extracts washed with brine (200 mL), dried (MgSO4), filtered, concentrated in vacuo, and purified by flash chromatography on silica gel (15% EtOAc/hexanes) to give 3-acetyl-2,5-dimethyl-1-(4-ethoxyphenyl)pyrrole as a tan solid: 1H NM (CDCl3, 500 MHz) δ 7.08-7.04 (m, 2H), 6.99-6.96 (m, 2H), 6.30 (s, 1H), 4.08 (q, 2H), 2.41 (s, 3H), 2.29 (s, 3H), 1.97 (s, 3H), 1.45 (t, 3H); MS (ESI) 258 (M+H)+.

Workup

temperatureAfter cooling to rt
extractionextracted with EtOAc (2×200 mL)
washthe combined extracts washed with brine (200 mL)
dry with materialdried (MgSO4)
filtrationfiltered
concentrationconcentrated in vacuo
custompurified by flash chromatography on silica gel (15% EtOAc/hexanes)

Sources & evidence

ORD record: ord-11d5c72f262d4f8280fa31883157ecbd
Source dataset: uspto-grants-2008_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07465730B2

Reaction notes

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