Phosgene → 2,2-Dimethyl-2,3-dihydro-1-benzofuran-7-sulfonyl isocyanate

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Reaction Steps

8 g of N-(2,3-dihydro-2,2-dimethylbenzo[b]furan-7-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 destilled off in vacuo, with the exclusion of moisture, to give 2,3-dihydro-2,2-dimethylbenzo[b]furan-7-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