2.4- Dimethoxy-3,5-dichloro-6-methylbenzoic

Di-0-methyl-3,5-diehloroorsellinic acid, 2,4-Dimethoxy-3,5-dichloro-6-methylbenzoic acid... 

Preparation by hydrogenolysis of 2, 2 -bis (benzyloxy)-3,5,5 -trichloro-4, 4 -dimethoxy-6,6 -dimethylbenzo-phenone (SM) with hydrogen in the presence of 10% Pd/C in ethyl acetate containing concentrated hydrochloric acid (5 drops) (>90%) [1339]. SM was obtained by Friedel-Crafts acylation of 5-(benzyloxy)-2-chloro-3-methoxy-toluene with 2-(benzyloxy)-3,5-dichloro-4-methoxy-6-methylbenzoic acid in the presence of trifluoroacetic anhydride in refluxing ethylene dichloride for 5 h (28%). 

Preparation by hydrogenolysis of 4,6, 6 -tris-(benzyloxy)-3,3 -dichloro-2, 4 -dimethoxy-2-methyl-benzophenone (SM) in ethyl acetate/tetrahydrofuran in the presence of 10% Pd/C at 25° (29%). SM was obtained by condensation of 4,6-bis(benzyloxy)-3-chloro-2-methylbenzoic acid with 4-chloro-3,5-dime-thoxyphenol benzyl ether in the presence of trifluoroacetic anhydride in methylene chloride under nitrogen for 20 min [1179]. m.p. 217-219° [1179] H NMR [1179], IR [1179], MS [1179]. 

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