Ethylene Glycol → 2,4-Dimethyl-3-carboxy-ethylpyrrole

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

2-(2-thienyl)pyrrole was prepared according to Kruse C. G. et al, Heterocycles 26 (1985) 3141 and formylated yielding 2-formyl-5-(2-thienyl)pyrrole according to Bullock E. et al. J. Chem. Soc. (1963) 2326 2,4-dimethyl-3-carboxyethylpyrrole was prepared as follows: 2-ethoxycarbonyl-3,5-dimethyl-4-methoxycarbonylethylpyrrole (1.5 g, 5.9 mmol) and potassium hydroxide (6.6 g) were dissolved in ethyleneglycol (50 ml). The reaction mixture was refluxed (190° C.) for 3 h under nitrogen atmosphere. Water (10 ml) was added and the mixture was refluxed for an additional 2 h. The cooled reaction mixture was diluted with water (200 ml), acidified with concentrated hydrochloric acid and extracted with diethylether. The organic extracts were pooled, dried with sodium sulphate and evaporated to dryness. The product was purified with column chromatography using silica as a stationary phase and dichloromethane:methanol (10:1, v:v) as an eluent. Fractions containing the product were pooled and evaporated to dryness yielding 720 mg (72%) of 2,4-dimethyl-3-carboxy-ethylpyrrole.

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