With N-Bromosuccinimide; In tetrachloromethane; for 3h;Reflux; Inert atmosphere;
A mixture of 3-methyl-lH-pyrrole-2-carboxylic acid ethyl ester (1.0 g, 6.5 mmol), NBS (1.22 g, 6.9 mmol) in CC14 (30 mL) was heated under reflux for 3 hours with nitrogen protection, and then cooled to room temperature and filtered. The filtrate was concentrated and the residue was purified by flash chromatography to give 4-bromo-3-methyl-lH-pyrrole-2-carboxylic acid ethyl ester (950 mg) as a white solid.
4-(3-chloropyridin-4-yl)-3-methyl-1H-pyrrole-2-carboxylic acid ethyl ester[ No CAS ]
Operation in experiment
With tetrakis(triphenylphosphine) palladium(0); sodium carbonate In 1,2-dimethoxyethane; water Inert atmosphere; Reflux;
15.2 Step 2: Preparation of 4-(3-chloro-pyridin-4-yl)-3-methyl-lH-pyrrole-2-carboxylic acid ethyl ester
Under a nitrogen atmosphere, 3-chloro-4-(4,4,5,5-tetramethyl-[l,3,2]dioxaborolan-2-yl)- pyridine (550 mg, 2.3 mmol), 4-bromo-3-methyl-lH-pyrrole-2-carboxylic acid ethyl ester (800 mg, 3.4 mmol) and Pd(PPh3)4 (270 mg, 0.23 mmol) were dissolved in DME (20 mL). A 2M aqueous sodium carbonate solution (4 mL) was added and the mixture was heated under reflux overnight. Then the mixture was cooled to room temperature and the solid was filtered off. The filtrate was concentrated and the residue was purified by flash chromatography to give 4-(3- chloro-pyridin-4-yl)-3-methyl-lH-pyrrole-2-carboxylic acid ethyl ester (100 mg).