反应详情

2 g (7.4 mmol) of 4-benzenesulphonyl-5-methylsulphanyl-2H-pyrazol-3-ylamine and 2.91 ml (18.3 mmol) of ethyl pivaloylacetate were added to 27 g of polyphosphoric acid and heated to 120° for 5 hrs. After cooling 100 ml of water were slowly added thereto and the mixture was extracted three times with CH2Cl2. The organic phase was dried (MgSO4), filtered and evaporated. Chromatography (SiO2, CH2Cl2/EtOAc) yielded 1.34 g (48%) of 3-benzenesulphonyl-5-tert-butyl-2-methylsulphanyl-pyrazolo[1,5-a]pyrimidin-7-ol as a colorless foam.

1. temperatureheated to 120° for 5 hrs
2. additionwere slowly added
3. extractionthe mixture was extracted three times with CH2Cl2
4. dry with materialThe organic phase was dried (MgSO4)
5. filtrationfiltered
6. customevaporated