Water → 3-methyl-4-oxo-5-(2-piperidin-1-yl-ethyl)-4,5,6,7-tetrahydro-1H-pyrrolo[3,2-c]pyridine-2-carbaldehyde

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Reaction Conditions

Reaction Steps

A stirred solution of N,N-dimethylformamide (1.68 ml) was added dropwise slowly with phosphorus oxychloride (0.9 ml, 9.65 mmol) under an argon atmosphere while maintaining the temperature at 0° C. Upon completion of the addition, the mixture was stirred for 15 minutes at room temperature, and cooled down to 0-5° C. in an ice-water bath. A mixture of 3-methyl-5-(2-piperidin-1-yl-ethyl)-1,5,6,7-tetrahydro-pyrrolo[3,2-c]pyridin-4-one (2.29 g, 8.77 mmol) in 10.5 ml of N,N-dimethylformamide was added dropwise to the above solution. Upon completion of the addition, the mixture was stirred for 2 hours at 0° C., added with cold water (5 ml), stirred for 5 minutes. The resulting mixture was adjusted to pH 12 with 10% aqueous sodium hydroxide solution and extracted with dichloromethane (30 ml×3). The combined organic extracts were washed with brine (15 ml), dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by silica gel column chromatography with dichloromethane:methanol (10:1) as eluents to give 3-methyl-4-oxo-5-(2-piperidin-1-yl-ethyl)-4,5,6,7-tetrahydro-1H-pyrrolo[3,2-c]pyridine-2-carbaldehyde (989 mg, 3 steps 31.7%) as a red oil which was used as such.

Provenance & Evidence