Water → 2-methyl-5,8-dihydro-4H-pyrazolo[3,4-c]thiazolo[5,4-f]isoquinoline

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Reaction Steps

A solution of 8-(4-methoxybenzyl)-2-methyl-5,8-dihydro-4H-pyrazolo[3,4-c]thiazolo[5,4-f]isoquinoline (0.6 g, 1.65 mmol) in trifluoroacetic acid (4 mL) was heated at 100° C. for 2 hours. The reaction mixture was poured into water (50 mL) and basified with aqueous potassium carbonate to pH of 11. The reaction mixture was then extracted with dichloromethane (3×75 mL). The combined organic extract was dried using sodium sulfate and concentrated under reduced pressure to give dark residue. The crude product was purified by flash column chromatography (SiO2, gradient from 100% chloroform to 2% methanol in chloroform) to give a residue, which was further purified by crystallization from methanol and isopropanol to give the desired product (0.076 g, 13%) as a solid. 1H NMR (DMSO-d6, 400 MHz): δ 13.49 (s, 1H), 8.04 (s, 1H), 8.02 (s, 1H), 3.16 (t, J=7.6 Hz, 2H), 3.0 (t, J=7.6 Hz, 2H), 2.70 (s, 3H); LCMS [M+H]: 243.

Provenance & Evidence