| abstract |
A process for manufacturing 5-chloromethyl-2,3-pyridine dicarboxylic acid anhydrides (I) n n n n n n n n n n n n wherein n Z is hydrogen or halogen; n Z 1 is hydrogen, halogen, cyano or nitro; n comprising the steps of n (i) reacting a compound of formula (II), n n n n n n n n n n n n n n n n wherein the symbols have the meaning given in formula (I), with a chlorinating agent, optionally in the presence of a radical initiator in a solvent selected from halogenated hydrocarbons, and n (ii) crystallizing the compound (I) formed in step (i) from a solvent selected from chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, dichloroethane, trichloromethane, dichloromethane, toluene, xylenes, ethyl acetate, methyl tert.-butyl ether, and mixtures thereof.n nCompounds (I) are useful intermediates in the synthesis of herbicidal imidazolinones. |