Efficient Method for Demethylation of Aryl Methyl Ether Using Aliquat-336

Abstract

A rapid method for selective cleavage of aryl methylethers can be achieved in the presence of a protic acid and a catalytic amount of phase-transfer catalyst (Aliquat-336). Aliquat-336 accelerates the rate of reaction and affords the corresponding phenols in excellent to good yields on a wide variety of substrates.

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GRAPHICAL ABSTRACT

Keywords:

• Aliquat-336
• aryl methyl ethers
• demethylation
• hydrobromic acid
• PTC

ACKNOWLEDGMENTS

S. B. W. and V. P. P. thank the Department of Science and Technology (DST), New Delhi, for financial support and the Council of Scientific and Industrial Research for a junior research fellowship, respectively.

Notes

Note. Reaction conditions: 2-methoxy naphthalene (20 mmol); 47% HBr (4.5 mmol equiv.); PTC (10 wt.% of substrate); temp. = 105 ± 5 °C; time = 2 h.

^a Conversion based on GC analysis.

Note. Reaction conditions: 2-methoxy naphthalene (20 mmol); 47% HBr (4.5 mmol equiv.); Aliquat-336 (10 wt.% of substrate); time = 2 h.

^a Conversion based on GC analysis.

Note. Reaction conditions: 2-methoxynaphthalene (20 mmol); 47% HBr (4.5 mmol equiv.); Aliquat-336 (10 wt.% of substrate); temp. = 105 ± 5 °C.

^a Reaction conditions: Aryl methyl ether (10 mmol); 47% HBr (4.5 mmol equiv. of substrate); Aliquat-336 (10 wt.% of substrate); temp. = 105 ± 5 °C.

^b Isolated yields.