Methylhydrazine → Pyrazolo(3,4-d)thiazolo(3,2-a)pyrimidin-4(1H)-one, 1-methyl-

Participants

Reaction Steps

In 8 ml of phosphorus oxychloride was dissolved 2.00 g (11.9 mmol) of 5-oxo-5H-thiazolo[3,2-a]pyrimidine [Zh. Org. Khim., 11, 2200 (1975)], and 1.13 ml of dimethylformamide was added dropwise to the solution with stirring under ice-cooling. Then, the reaction mixture was heated under reflux for 30 minutes. After concentration of the reaction mixture to dryness under reduced pressure, the oily residue was dissolved in 60 ml of ethanol under ice-cooling. To the solution were added 10 ml of triethylamine and 2.52 ml (47.6 mmol) of methylhydrazine, followed by heating under reflux for 3 hours. After evaporation of the solvent, the residue was subjected to partition between chloroform and water, and the chloroform layer was concentrated to dryness under reduced pressure. The residue was subjected to silica gel column chromatography and eluted with chloroform to give 1.74 g (71%) of Compound 51. The compound was recrystallized from dimethylformamide/water for purification.

Provenance & Evidence