Magnesium Carbonate → Ethyl 2-propylthiazole-5-carboxylate

A mixture of 38 g of thiobutyramide, 54.2 g of ethyl 2-formyl-2-chloro-acetate, 185 ml of dioxane and 22 g of magnesium carbonate was heated for 4 hours at 60°C and the precipitate formed was removed by filtration. The dioxane was distilled from the filtrate and the residue was taken up in 665 ml of a 1-1 ethyl ether-water mixture. The ether phase was recovered by decantation and was washed with aqueous 10% hydrochloric acid solution and then with water until the wash waters were neutral, dried over magnesium sulfate and distilled to dryness. The residue was distilled to obtain 57 g of ethyl 2-n-propylthiazol-5-carboxylate boiling at 95°-106°C under 0.5 mm Hg.