Methylamine → 3-Methyl-1,2,3,4-tetrahydroquinazoline-2,4-dione

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Reaction Steps

6 g isatoic anhydride was stirred in 100 ml dry tetrahydrofurane (THF) and methylamine was passed through the mixture for 5 min. The resulting solution was evaporated and the residue was again dissolved in THF (100 ml) and charged with 15 ml 30% phosgene solution in toluene. The mixture was heated to reflux and additional 15 ml phosgene solution was added. After 4 hours reflux the mixture was cooled and evaporated to dryness. The residue was treated with water and the crystals were collected by filtration. The yield was 3.5 g. M.p. 240.4° -240.5° C. In the same manner, from the appropriate substituted isatoic anhydrides, the following compounds were synthesized:

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