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US 2006/0052463 A1Published application
Process for regioselective demethylation of p-methoxy group in phenolic ester and diaryl ketone moieties
AssigneeCouncil of Scientific and Industrial Research
InventorsArvind Negi, Sunil Chattopadhyay, Sachin Srivastava, Asish Bhattacharya
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Abstract
Demethylation of 3′,4′-dimethoxy or 3′,4′,5′-trimethoxy benzoic ester of a phenol is carried out in the presence of an excess of aluminum halide in an organic solvent to get 4′-Hydroxy, 3′-methoxy or 4′ hydroxy, 3′,5′-dimethoxy benzoic acid ester of a phenol. The reaction is also applicable to 3′,4′,5′-trimethoxy diaryl ketone and some natural products like reserpine.
Claims7
A process for regioselective demethylation of a compound of general formula 1
- to obtain a compound of general formula 2,
- said process comprises steps:
- (a) mixing compound of formula 1 with an organic solvent;
- (b) adding Lewis acid to mixture of step (a) and stirring the reaction mixture at a temperature in the range of 0 to 80° C. for a time period in the range of 5 minutes to 3 hours;
- and
- (c) adding mineral acid into the reaction mixture of step (b), further stirring the mixture for a time period in the range of 2 to 10 minutes to obtain a demethylated compound of general formula 2.
3 more elements
Dependencies are inferred from the claim text.