PURPOSE: To obtain a 1,1,3,3-tetrachloro-1,3-dihydroisobenzofuran derivative useful as an intermediate for producing an agrochemical industrially and advanta geously by treating a phthalide derivative having a specific structure with phos phorus trichloride and chlorine.
CONSTITUTION: This compound of formula II is obtained by treating a phthalide derivative of formula I (R is a group or an atom insert to a reaction; (n) is 1-4) with phosphorus trichloride and chlorine preferably at 20-100°C usually for 0.2-24 hours. The amount of phosphorus trichloride is 3-10 mols and that of chlorine is 3-6 mols based on 1 mol of the compound of formula I. For example, when phthalide is used as a compound of formula I, 1,1,3,3-tetrachloro-1,3- dihydroisobenzofuran is obtained as the compound of formula II and when 4,5-dichlorophalide is used as the compound of formula I, 1,1,3,3,5,6- hexachloro-1,3-dihydroisobenzofuran is obtained as the compound of formula II.
YOSHIYAMA TORANORI
YAMADA YOSHIMI
