Isatoic Anhydride → 3-Ethyl-2,4(1H,3H)-quinazolinedione

Participants

Reaction Steps

To a mixture of 12.23 g of ethylamine hydrochloride, 35 ml 4M sodium hydroxide and 175 ml methylene chloride was added 16,3 g isatoic anhydride. This mixture was stirred for 4 hours and the aqueous phase was made basic with 4M sodium hydroxide. The organic phase was evaporated in vacuo. The residue was dissolved in 300 ml of tetrahydrofuran (THF) and 75 ml phosgene solution (20% in toluene) was added. The resulting mixture was stirred at 80° C. for two hours. The precipitate was filtered off and the mother liquor was evaporated leaving 5.2 g of the title compound. M.p. 189.8°-189.9° C.

Provenance & Evidence