Herbicidal 3-isopropyl-benzo-2-thia -1,3-diazinone 2,2,-di:oxide mfr.

摘要

3-Isopropyl-benzo-2-thia- 1,3-diazinone-(4)-2,2-dioxide (I) is prepd. by reacting N,N'-diisopropylurea with PCl3 and Cl2 in the presence of oleum and sulphuric acid, condensing the thus-obtained isopropyl sulphamoyl chloride with methyl anthranilate at room temp without a solvent but in the presence of excess N,N-diethylaniline cyclising the obtd. N-isopropyl-N' -o-carbomethoxyphenyl sulphamide in the presence of sodium methylate, extracting the obtd. crude (I) with aq. methanol, adding water to form a sediment of impurities, removing the sediment and isolating (I).