Methanol → 4-(3-Acetyl-5-ethoxy-2-methyl-1,4-dihydropyrido[2,3-d]pyridazin-4-yl)-3-methoxybenzonitrile

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Reaction Steps

65 mg (0.193 mmol) of 4-(3-acetyl-2-methyl-5-oxo-1,4,5,6-tetrahydropyrido[2,3-d]pyridazin-4-yl)-3-methoxybenzonitrile are mixed under an argon atmosphere with 4 ml of abs. dichloromethane and 73.4 mg (0.386 mmol) of triethyloxonium tetrafluoroborate. After a reaction time of 2 hours at room temperature (reaction check by HPLC), conversion remains incomplete. Two further equivalents of triethyloxonium tetrafluoroborate are added. After a further reaction time of 3 h, the mixture is mixed with 5 ml of methanol and 0.5 ml of water and again stirred for 2 h. It is then diluted with 20 ml of water and extracted three times with dichloromethane. The combined organic phases are dried with sodium sulfate, and the solvent is removed in a rotary evaporator. The residue is purified by preparative HPLC (eluent: acetonitrile/water with 0.1% formic acid, gradient 20:80→95:5). 8 mg (11.3% of theory) of the title compound are obtained.

Provenance & Evidence