Carbon Dioxide → 2,6-Dihydro-2-methyl-4-(2-methylpropyl)-6-phenylmethyl-1h-pyrrolo[3,4-d]pyridazin-1-one-5-carboxylic acid

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Reaction Conditions

Reaction Steps

Butyl lithium (2.5M in hexanes, 2.35 m) was added dropwise to a stirred solution of diisopropylamine (0.85 ml) in dry tetrahydrofuran (10 ml) at 0° C., under nitrogen. The reaction was stirred at 0° C. for 30 minutes, then cooled to −78° C. To this was added a solution of 2,6-dihydro-2-methyl-4-(2-methylpropyl)-6-(1-phenylmethyl)-1H-pyrrolo[3,4-d]pyridazin-1-one (1.5 g, prepared as in Example 14 step b) in dry tetrahydrofuran (10 ml), and stirring was continued for 30 minutes. This anion was then added to an excess of solid carbon dioxide. The reaction was allowed to warm to room temperature overnight, and was then quenched by the addition of water. The mixture was extracted into ethyl acetate, washed with brine, dried and evaporated to give a yellow oil, which was chromatographed, eluting with ethyl acetate:isohexane(3:7), to give the sub-title compound as a yellow solid (0.91 g).

Provenance & Evidence