Phosphorus oxychloride → Ethyl 2-(3-benzenesulphonyl-7-chloro-5-methyl-2-methylsulphanyl-pyrazolo[1,5-a]pyrimidin-6-yl)-aceate

Participants

Reaction Steps

A suspension of 1.5 g (3.56 mmol) of ethyl 2-(3-benzenesulphonyl-7-hydroxy-5-methyl -2-methylsulphanyl-pyrazolo[1,5-a]pyrimidin-6-yl)-acetate in 30 ml of POCl3 was heated at reflux for 4 hrs. The reaction solution was cooled to RT and evaporated. The residue was treated with 100 ml of ice-water and the pH value of the solution was adjusted to 8 with sat. NaHCO3 solution. The aqueous phase was extracted three times with 70 ml of CH2Cl2, and the organic phases were dried (MgSO4), filtered and evaporated.Chroma-tography (SiO2, CH2Cl220:1) of the residue yielded 1.0 g (94%) of ethyl 2-(3-benzenesulphonyl-7-chloro-5-methyl-2-methylsulphanyl-pyrazolo[1,5-a]pyrimidin-6-yl)-aceate as a pale yellow solid.

Provenance & Evidence