87931-26-8Relevant articles and documents
Degradation of O-Arylisoureas in Alkali: A Low-temperature Chapman-type Rearrangement
Suttle, Nicola A.,Williams, Andrew
, p. 1369 - 1372 (2007/10/02)
NN'-Di-isopropyl-O-arylisoureas are demonstrated to rearrange intramolecularly to the corresponding NN'-di-isopropyl-N'-arylurea in alkaline solution.The large negative Broensted-type βL value (-2.3) for the reaction measured against the pK of the corresponding phenol and a modest entropy of activation are consistent with a 1,3-aryl migration.The high efficiency of the migration compared with that of the Chapman rearrangement of O-aryl imidoethers is attributed to the greater internal nucleophilicity of the imino nitrogen, which in the present case bears a negative charge.