2,2-Di:chloro-1,3-benzodioxole derivs. prodn. - by reacting 2-unsubstituted cpd. with chlorine and phosphorus tri:chloride, useful as pesticide intermediates

摘要

Prodn. of 2,2-dichloro-1,3-benzodioxoles of formula (I) comprises reacting unsubstd. cpd. of formula (II) with Cl2 in presence of PCl3. In the formulae, R = H or 1-6C alkyl. Reaction is pref. at 80-180 (esp. 85-120) deg.C, using 0.2-1.2 (esp. 0.8-1) mole PCl5 per mole (II), opt. in presence of inert: solvent, esp. chlorobenzene, 1,2-dichlorobenzene or CCl4. USE/ADVANTAGE - (I) are intermediates for pesticides (see EP 198797 or DE 2819788). This method is better (for technical, economic and ecological reasons) than processes using PCl5 because PCl3 and Cl2 are easy to handle liq. or gas. Aromatic-ring chlorination is almost entirely avoided and where a solvent is used this can be recovered for recycle.