Glyoxal → 8-(4-Fluorophenyl)-7-(pyridin-4-yl)pyrazolo[1,5-b][1,2,4]triazine

Participants

Reaction Steps

To a solution of 5-amino-4-(4-fluorophenyl)-3-(pyridin-4-yl)pyrazole (1.674 g) in ethanol (33 ml) was added O-mesitylsulfonylhydroxylamine (2.362 g). The mixture was stirred at ambient temperature for 30 minutes and to the mixture was added a solution of glyoxal in water (40%, 955 mg). The mixture was refluxed for 4 hours and cooled. The reaction mixture was poured into an aqueous saturated sodium bicarbonate solution and the separated oil was extracted with dichloromethane. The extract was washed with brine, dried and concentrated in vacuo. The residue was purified by column chromatography on silica gel and the obtained oil was crystallized from ethanol to give 8-(4-fluorophenyl)-7-(pyridin-4-yl)pyrazolo[1,5-b][1,2,4]triazine (63 mg).

Provenance & Evidence