4- Benzyloxy-3,6-dimethoxy-2-methylbenzoic acid

Preparation by hydrogenolysis of 2, 4, 6-tris-(benzyloxy)-3-chloro-2,4-dimethoxy-6 -methyl-benzophenone (SM) in ethyl acetate/tetrahydrofuran in the presence of 10% Pd/C at 25°. SM was obtained by condensation of 2,4-bis(benzyloxy)-6-methylbenzoic acid with 4-chloro-3,5-dimethoxyphenol benzyl ether in the presence of trifluoroacetic anhydride in methylene chloride under nitrogen for 15 min (61%) [1179]. m.p. 181-182° [1179] H NMR [1179], IR [1179], MS [1179]. 

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%). 

Hydroxy-4-0-methylum-bilicaric acid 184 168-169 By condensation of 3-benzyloxy-2,4-dimethoxy-6-methylbenzoic acid and benzyl lecanorate with TFAA and subsequent debenzylation (223)... 

From 2,4-dimethoxy-6- -pentylbenzoic acid and 4-benzyloxy-2,3-dihydroxy-6- -propylbenzoate withTFAA and subsequent debenzylation From 2,4-dibenzyloxy-6-methylbenzoic acid and benzyl 2,4-dihydroxy-3,6-di-methylbenzoate with TFAA and subsequent debenzylation 101... 

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See also in sourсe #XX -- [ ]

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