Methyl chloroglyoxylate → Methyl 2-(2-(3-chlorophenyl)-7-(4-fluorophenyl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-oxoacetate

Participants

Reaction Steps

To a stirred mixture of 6-bromo-7-chloro-2-(3-chlorophenyl)-5-methylpyrazolo[1,5-a]pyrimidine (0.179 g, 0.5 mmol) and copper(I) bromide (0.072 g, 0.500 mmol) in THF (3 mL) was added dropwise a pre-mixed solution of 2M 4-fluorophenylmagnesium bromide/ether (3.00 ml, 6.00 mmol) and 0.5M LiCl/THF (6.00 ml, 3.00 mmol) over 15 min. After 2 h, added at once methyl 2-chloro-2-oxoacetate (0.368 ml, 4.00 mmol) to the dark solution. After 1 h, the reaction was diluted with Et2O (50 mL), quenched with Na2CO3 (1 mL), washed with 10 mL each water and brine, dried (Na2SO4), filtered and concentrated to give orange paste which was purified by prep-HPLC to afford methyl 2-(2-(3-chlorophenyl)-7-(4-fluorophenyl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-oxoacetate (0.0644 g, 0.152 mmol, 30.4% yield) as yellow solid contaminated with some impurity. 1H NMR (500 MHz, CDCl3) δ: 7.88 (s, 1H), 7.81-7.74 (m, 1H), 7.73-7.67 (m, 2H), 7.35 (d, J=5.2 Hz, 2H), 7.31-7.24 (m, 2H), 6.97 (s, 1H), 3.44 (s, 3H), 2.67 (s, 3H). LCMS (M+H) calcd for C22H16ClFN3O3: 424.09. found: 424.3. LCMS (M+H) calcd for C22H16ClFN3O3: 424.09. found: 424.3.

Provenance & Evidence