2-(Benzenesulfonyl)-3-phenyloxaziridine → Methyl 2-(7-chloro-2-(3-chlorophenyl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-hydroxyacetate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of methyl 2-(7-chloro-2-(3-chlorophenyl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)acetate (7.8 g, 22.27 mmol) in THF (40 mL) at −78° C. was added KHMDS (44.5 mL, 22.27 mmol) dropwise over 30 min. The mixture was stirred at −78° C. for 30 min. A solution of 3-phenyl-2-(phenylsulfonyl)-1,2-oxaziridine (8.73 g, 33.4 mmol) in THF (50 mL) was added over 30 min and the reaction mixture was stirred for additional 2 h at −78° C. The reaction mixture was quenched with saturated NH4Cl aqueous solution (40 mL). The reaction mixture was allowed to warm to room temperature and then diluted with ethyl acetate (200 mL). The organic phase was washed with water and brine and dried with sodium sulfate. The solvent was evaporated. Purification by silica gel chromatography provided the title compound (4.2 g, 51.5%). 1H NMR (500 MHz, CHLOROFORM-d) δ 8.05-7.97 (m, 1H), 7.88 (dt, J=6.7, 1.8 Hz, 1H), 7.44-7.38 (m, 2H), 6.93 (s, 1H), 5.76 (s, 1H), 3.84 (s, 3H), 2.62 (s, 3H).

Provenance & Evidence