Perchloric Acid → HCID 117626364, compound

Participants

Reaction Steps

To a stirred solution of (S)-ethyl 7-chloro-6-(2-ethoxy-1-hydroxy-2-oxoethyl)-5-methylpyrazolo[1,5-a]pyrimidine-2-carboxylate (200 mg, 0.585 mmol) in CH2Cl2 (6 mL) and t-butyl acetate (4 mL) at rt was added perchloric acid (0.151 mL, 1.756 mmol). The reaction flask was sealed. After stirring for 3 h, the reaction mixture was diluted with CH2Cl2 (50 mL), carefully quenched with sat. aq. NaHCO3 (5 mL). The organic layer was separated and washed with brine (5 mL), dried (Na2SO4), filtered and concentrated in vacuo to give a yellow liquid. This crude product was purified by flash column chromatography on a silica gel column using (10-50% EtOAc/Hex as eluant) to afford the desired (S)-ethyl 6-(1-(tert-butoxy)-2-ethoxy-2-oxoethyl)-7-chloro-5-methylpyrazolo[1,5-a]pyrimidine-2-carboxylate (200 mg, 0.503 mmol, 86% yield) as viscous oil. 1H NMR (400 MHz, CDCl3) δ 7.19 (s, 1H), 5.66 (s, 1H), 4.52 (q, J=7.2 Hz, 2H), 4.25-4.19 (m, 2H), 2.72 (s, 3H), 1.51-1.45 (m, 3H), 1.28 (s, 9H), 1.26-1.21 (m, 3H). LCMS (M+1)=398.25.

Provenance & Evidence