Benzene → Pyrazine, 2-methoxymethyl-5-methyl-, 4-oxide

Participants

Reaction Steps

2-Hydroxymethyl-5-methylpyrazine-4-oxide (3.5 g) was dissolved under stirring in a solution of 8 ml of thionyl chloride in 20 ml of dry benzene containing 0.5 g of ZnCl2, keeping the temperature below 30° C. The reaction mixture was cautiously warmed 3 hours at 60° C., then cooled to room temperature, and filtered. The solvent was evaporated under reduced pressure. The oily residue was dissolved in a solution of sodium methoxide in methyl alcohol, previously prepared dissolving 0.6 of sodium in 30 ml of methyl alcohol. After refluxing 4 hours, the reaction solution was cooled at room temperature, filtered and evaporated to dryness. The residue was taken up with water and repeatedly extracted with ethyl ether. The organic phase was washed with water, dried and the solvent was evaporated to dryness; the residue treated with pentane gave 2-methoxymethyl-5-methylpyrazine-4-oxide (1.5 g), m.p. 69°-72° C.

Provenance & Evidence