| 摘要 |
beta-bromo- or beta-chloro-alkyl isocyanates, of general formula: (where X is Cl or Br; R', R2, R3 and R4 are H or (cyclo)-aliphatic, aromatic or heterocyclic contg. up to 22C atoms, opt. with halogen atoms or alkoxy carbonyl, cyano, nitro, alkoxy and/or aryloxy as substituents). Prepd. by treating N-bromo- or N-chloro-beta-lactams with radical generating catalyst at -50 to +250, degrees C by a transposition reaction; effected in the presence of an ethylene and/or acetylene cpd., which boils at less than 170 degrees C, and solvent, inert towards the isocyanates. - Catalyst comprises H2O2, mineral peroxides and/or hydroperoxides, and/or azo-bis-isobutyronitrile. |
