N,N-Dimethylaniline → 5-Chloro-7-ethoxycarbonyl-3-methyl-s-triazolo[4,3-a]pyrimidine

Participants

Reaction Conditions

Reaction Steps

To a suspension of the product obtained in Step 1 (4.3 g) in 50 ml of phosphorus oxychloride was dropwise added 2.6 g of N,N-dimethylaniline at room temperature. The mixture was heated at 80° C. for one hour, excess phosphorus oxychloride was removed by distillation under reduced pressure, and the remaining reddish brown oil was shaken with 300 ml dichloromethane and 300 ml of water. The pH was adjusted to 7 to 8 with saturated sodium bicarbonate solution, the dichloromethane layer was collected, and the aqueous layer was again extracted with 200 ml of fresh dichloromethane. The chloroform layers were joined together, washed with saturated sodium chloride solution and dried over anhydrous magnesium sulfate. The dried filtrate was concentrated under reduced pressure, and the oily product left was purified by silica gel chromatography, giving 4.2 g of the objective compound as faint yellow crystals.

Provenance & Evidence