tert-Butyl acetate → (S)-methyl 2-(tert-butoxy)-2-(2-(3-chlorophenyl)-7-isopropyl-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)acetate

Participants

Reaction Steps

To a stirred solution of (S)-methyl 2-(2-(3-chlorophenyl)-7-isopropyl-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-hydroxyacetate (0.069 g, 0.185 mmol) and tert-butyl acetate (1.247 ml, 9.23 mmol) in CH2Cl2 (5 mL) was added 70% perchloric acid (0.048 ml, 0.554 mmol) at rt. After 3 h, the reaction mixture was diluted with Et2O (35 mL), washed with sat Na2CO3 (2×5 mL), brine (5 mL), dried (Na2SO4), filtered and concentrated to give colorless paste which was purified by prep-HPLC to afford (S)-methyl 2-(tert-butoxy)-2-(2-(3-chlorophenyl)-7-isopropyl-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)acetate (0.0496 g, 0.244 mmol, 62.5% yield) as white solid. 1H NMR (500 MHz, CDCl3) δ: 7.98 (t, J=1.7 Hz, 1H), 7.87 (dt, J=7.6, 1.4 Hz, 1H), 7.41-7.32 (m, 2H), 6.77 (s, 1H), 5.42 (s, 1H), 4.07 (dt, J=13.6, 6.9 Hz, 1H), 3.71 (s, 3H), 2.73 (s, 3H), 1.68 (d, J=7.0 Hz, 3H), 1.56 (d, J=7.0 Hz, 3H), 1.26 (s, 9H). LCMS (M+H) calcd for C23H29ClN3O3: 430.19. found: 430.3.

Provenance & Evidence