4,4-Dimethoxy-2-butanone → 2-Methoxy4-(3-methyl-pyrazol-1-yl)-benzoic acid, methyl ester

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 4-hydrazino-2-methoxybenzoic acid, methyl ester hydrochloride (0.88 g) from Example 104 and one drop of concentrated hydrochloric acid in a 1:1 water/methanol (10 ml) mixture was added acetylacetaldehyde dimethylacetal (0.53 g). The reaction was heated to 90° C. for 5 minutes. The reaction was concentrated in vacuo and partitioned between 1 N sodium hydroxide (10 ml) and ethyl acetate (50 ml). The organic phase was removed and washed with brine, dried over anhydrous magnesium sulfate and filtered. Evaporation of the solvent in vacuo afforded a brown oil which was combined with a previous lot (0.54 g) and recrystallized three times from diisopropyl ether to give 2-methoxy-4-(3-methyl-pyrazol-1-yl)-benzoic acid, methyl ester (0.5 g). m.p. 167-169° C., MS, m/z: 246 (M)+.

Provenance & Evidence