Methanol → 2-Pyrazinecarboxylic acid, 5-methyl-, methyl ester

Participants

Reaction Steps

The reaction was carried out, under nitrogen, in a 1 L×4 neck flask equipped with a mechanical stirrer, water condenser (with gas inlet), and a thermocouple. The reactor was charged with 5-methylpyrazinecarboxylic acid (100 g), and acidic cation exchange resin (20 g), and methanol (300 g). The mixture was stirred at reflux for about 20 h. After the reaction was complete (analyze with GC or GC/MS), the resin was removed by pressure filtration. The resin was rinsed with methanol and about 75% of the solvent was removed under reduced pressure. The resulting suspension was allowed to stand at room temperature overnight, and then in an ice-bath for 3 h. The solid was collected by filtration and washed with ice-cold methanol (2×80 g). Drying under vacuum at room temperature (25 inches of Hg) yielded 102.4 g (93%) of 5-methyl-2-pyrazinecarboxylic acid, methyl ester that was suitable for further use.

Provenance & Evidence