1H-Pyrrole-2-carboxylic acid, 4-(1,1-dimethylethyl)-, ethyl ester synthesis
- Product Name:1H-Pyrrole-2-carboxylic acid, 4-(1,1-dimethylethyl)-, ethyl ester
- CAS Number:746671-35-2
- Molecular formula:C11H17NO2
- Molecular Weight:195.26
507-20-0
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2199-43-1
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746671-35-2
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131475-04-2
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125261-17-8
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Yield:746671-35-2 7% ，125261-17-8 52% ，131475-04-2 7%
Reaction Conditions:
with gallium(III) trichloride in carbon disulfide; for 0.75 h;Reflux;
Steps:
34.1
To a solution of gallium trichloride (4.00 g, 22.7 mmol) in carbon disulfide (30 mL) at room temperature were added ethyl pyrrole-2-carboxylate (2.87 g, 20.6 mmol) and 2-chloro-2-methylpropane (2.50 mL, 23.0 mmol). The mixture was then heated at reflux for 45 min. The reaction mixture was cooled to room temperature and was poured onto a mixture of ice and 1N HCl. The aqueous layer was extracted with dichloromethane. The organic layer was washed with saturated NaHCO3, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by silica gel chromatography (0-10% ethyl acetate/heptanes) to afford 4-tert-butyl-1H-pyrrole-2-carboxylate (260 mg, 7%), ethyl 5-tert-butyl-1H-pyrrole-2-carboxylate (2.1 g, 52%) and ethyl 3,5-di-tert-butyl-1H-pyrrole-2-carboxylate (352 mg, 7%) each isolated as white solids. Ethyl 4-tert-butyl-1H-pyrrole-2-carboxylate: 1H NMR (300 MHz, CDCl3) δ 1.25 (s, 9H), 1.35 (t, J=7.1 Hz, 3H), 4.30 (q, J=7.1 Hz, 2H), 6.76 (dd, J=2.7, 1.8 Hz, 1H), 6.85 (dd, J=2.3, 1.9 Hz, 1H), 8.83 (br. s, 1H).
References:
US2016/95858,2016,A1 Location in patent:Paragraph 2933; 2934
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2199-43-1
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847955-92-4
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746671-35-2
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131475-04-2
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917-92-0
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2999-46-4
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746671-35-2
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1123725-70-1
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