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21st September 2011 @ 07:57
Product obtained in 82% yield.

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Hydrolysis of Ethyl 1-(4-fluorophenyl)-2,5-dimethyl-1H-pyrrole-3-carboxylate to give the desired acid(1-(4-Fluorophenyl)-2,5-dimethyl-1H-pyrrole-3-carboxylic acid)

Reaction Scheme

Reaction start time: 17.30 EST 21/09/11
PMY 6-1 (300 mg, 1.15 mmol, 1 equiv.) was stirred in 20% NaOH (5 mL, approx 17 equiv.). Heated to reflux. After 15.5 hours at reflux the mixture was cooled and acidified with 2M HCl. The precipitate was filtered and then recrystallised from EtOH/water to obtain a brown solid (185 mg). 1H NMR consistant with PMY 3-8-a, 1:2.59 SM:Product. Mother liquor extracted with Et2O (3 × 10 mL) and the extract concentrated under reduced pressure. The residue and brown solid (185 mg) were dissolved in EtOH (approx 10 mL), 20% NaOH (10 mL) was added and the reaction heated to reflux. After 1 hour, TLC shows reaction complete. Acidified with 2M HCl, fine precipitate forms. Attemted filtration but went through sinter. Extracted with Et2O (3 × 10 mL), washed with brine and dried (MgSO4) then concentrated under reduced pressure to brown solid (219 mg, 82% after drying further under vacuum).

TLC (25% EtOAc/petrol) visualised with UV and vanillin:
TLC


Mass Spectrometry:
m/z (ESI-) 232 [M-H]-, 100%.

NMR:
1H NMR of partially converted material
1H NMR complete rxn

NMR of complete reaction is DCM wet from transfers. Drat.

Risk and Hazard Assessment:
Risk Assessment
Linked Posts
Attached Files
Reaction Scheme
Risk Assessment
1H NMR of partially converted material
TLC
1H NMR complete rxn