Pyridine → 3-Chloro-3-(2-ethoxypyridin-3-yl)-2-oxoindoline-5-carbonitrile

Beteiligte Stoffe

Reaktionsschritte

Under an atmosphere of nitrogen, 6.00 g (20.32 mmol) of the 5-cyano-3-hydroxy-3-(2-ethoxypyridin-3-yl)-1,3-dihydroindol-2-one were suspended in 60 ml of anhydrous dichloromethane (dried over molecular sieve). 2.30 ml (28.45 mmol) of pyridine were then added. The reaction mixture was cooled to a temperature of 0° C., and 2.06 ml (28.45 mmol) of neat thionyl chloride were then added dropwise (exothermic reaction). The mixture was stirred at room temperature for one hour. The formation of a yellow suspension was observed. The course of the reaction was monitored by thin-layer chromatography (TLC) (silica gel, dichloromethane/methanol in a ratio of 95:5). The reaction mixture was carefully poured into ice-water. After 15 minutes of stirring, the organic phase was removed. The aqueous phase was extracted with dichloromethane (2×). All organic phases were combined, dried over magnesium sulphate and filtered, and the solvent was removed under reduced pressure. The product gave 5.70 g (18.17 mmol, 89%) of 3-chloro-3-(2-ethoxypyridin-3-yl)-2-oxoindoline-5-carbonitrile as an amorphous solid which was used without further purification for the next reaction. ESI-MS [M+H+]=314.1 calculated for C16H12ClN3O2=313.75

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