| Popis: |
tert-Butylsulfinyl chloride (1) reacts smoothly with N′-(di)methyl- and N′-(di)phenyl-N-hydroxyurea (2) in acetone at room temperature, in the presence of two equivalents of pyridine. An intermediate O-tert-butylsulfinyl-N-hydroxyurea (3) is postulated, which rearranges via a radical cage mechanism to give the corresponding N-tert-butylsulfonylurea as the recombination product. Several escape products are also isolated. This thermally induced rearrangement involves homolytic cleavage of the N-O bond in 3. The process is accompanied by pronounced 1H-CIDNP effects, which may be interpreted using Kaptein's rule. The fate of the N′-(di)substituted carbamoylaminyl radicals, formed initially within the radical pair, is discussed. N′,N′-diphenyl-N-hydroxyurea shows deviant behaviour and the major reaction product is in this case diphenylamine. |
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