Perchloric Acid → (S)-methyl 2-(2-(3-bromophenyl)-7-iodo-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-(tert-butoxy)acetate

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Reaction Steps

To a stirred solution of (S)-methyl 2-(2-(3-bromophenyl)-7-iodo-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-hydroxyacetate (1 g, 1.992 mmol) in CH2Cl2 (30 mL) and t-butyl acetate (21.00 mL) at rt was added 70% perchloric acid (0.513 mL, 5.97 mmol). After 3 h, the reaction mixture was diluted with CH2Cl2 (100 mL), carefully quenched with sat. NaHCO3 (50 mL), organic layer separated and washed with brine (100 mL), dried (Na2SO4), filtered and concentrated to give yellow liquid. This was purified by flash column chromatograpgy on silica gel column using (10-50% EtOAc/Hex as eluant) to afford (S)-methyl 2-(2-(3-bromophenyl)-7-iodo-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-(tert-butoxy)acetate (800 mg, 1.433 mmol, 72.0% yield) as yellow solid. 1H NMR (500 MHz, CDCl3) δ: 8.20 (s, 1H), 7.95 (d, J=7.7 Hz, 1H), 7.56 (d, J=7.9 Hz, 1H), 7.37 (t, J=7.9 Hz, 1H), 7.08 (s, 1H), 5.59 (s, 1H), 3.76 (s, 3H), 2.70 (s, 3H), 1.32 (s, 9H). LCMS (M+H)=560.15.

Provenance & Evidence