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 4 M 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