N,N-Dimethylaniline → HCID 178431609, compound

Participants

Reaction Steps

To the crude product (378 mg) of 5,7-dihydroxy-6-methylpyrazolo[1,5-a]pyridine-4-carbonitrile (5), N,N-dimethylaniline (380 μL) was added and this mixture was suspended in phosphoryl chloride (20 mL). This suspension was stirred under reflux with heating for 3 h. After the reaction solution was cooled to room temperature, excessive phosphoryl chloride was removed under reduced pressure. The residue was diluted with ethyl acetate and water, and two layers were separated. The organic layer was reversely extracted with saturated aqueous sodium hydrogen carbonate solution, and the aqueous extract was combined with the aqueous layer. The pH of combined aqueous layers were adjusted to 10 with 2 mol/L aqueous sodium hydroxide solution, and the solution was stirred for 4 days. This mixture was acidified to pH 2 with 1 mol/L hydrochloric acid and extracted with ethyl acetate three times. The combined organic layers were washed with a mixture of brine and 1 mol/L hydrochloric acid (5:1) and dried over sodium sulfate. The solvent was removed under reduced pressure to obtain the title compound (13) (211 mg), a part of which was purified with preparative HPLC and the NMR spectrum was recorded.

Provenance & Evidence