Hydrochloric Acid → Ethyl 8-ethoxy-1-methyl-4,5-dihydro-1h-pyrazolo[4,3-h]quinazoline-3-carboxylate

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Reaction Steps

To a stirred suspension of ethyl 1-methyl-8-(methylsulfonyl)-4,5-dihydro-1H-pyrazolo[4,3-h]quinazoline-3-carboxylate (46 mg, 0.137 mmol) and phenylthiol (16 μl, 17 mg, 0.15 mmol) in ethanol (1 mL), 1N sodium hydroxide (150 μl, 0.15 mmol) was added at room temperature under an argon atmosphere. After the mixture was stirred for 3 days, 1N hydrochloric acid (150 μl, 0.15 mmol) was added and the solvent removed under vacuo. By chromatography on silica gel (eluant: dichloromethane/methanol 97/3), 13 mg of ethyl 1-methyl-8-(phenylthio)-4,5-dihydro-1H-pyrazolo[4,3-h]quinazoline-3-carboxylate and 10 mg of ethyl 8-ethoxy-1-methyl-4,5-dihydro-1H-pyrazolo[4,3-h]quinazoline-3-carboxylate were isolated.

Provenance & Evidence