Phosgene → 3,4-Dihydro-2,2-dioxo-3-methyl-1,2-benzoxathiin-8-ylsulfonylisocyanate

Participants

Reaction Steps

10 g of N-(3,4-dihydro-2,2-dioxo-3-methyl-1,2-benzoxathiin-8-ylsulfonyl)-N'-methylurea are dispersed in 400 ml of absolute chlorobenzene and the dispersion is saturated with phosgene at about 130° C., whereupon a clear solution forms. The solvent is then distilled off in vacuo, with the exclusion of moisture, to give 3,4-dihydro-2,2-dioxo-3-methyl-1,2-benzoxathiin-8-ylsulfonylisocyanate in the form of an oil, which can be used without further purification for obtaining the fused N-phenylsulfonyl-N'-pyrimidinylureas and N-phenylsulfonyl-N'-triazinylureas of the formula I.

Provenance & Evidence