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

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:

1. customThe resulting solution was evaporated
2. dissolutionthe residue was again dissolved in THF (100 ml)
3. additioncharged with 15 ml 30% phosgene solution in toluene
4. temperatureThe mixture was heated
5. temperatureto reflux
6. additionadditional 15 ml phosgene solution was added
7. temperatureAfter 4 hours reflux the mixture
8. temperaturewas cooled
9. customevaporated to dryness
10. additionThe residue was treated with water
11. filtrationthe crystals were collected by filtration
12. customIn the same manner, from the appropriate substituted isatoic anhydrides, the following compounds were synthesized

ORD record

ord-14fbae1203604621bbbd90a023bb985d

Source dataset

uspto-grants-1989_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04873244