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Demethylation of aryl methyl ethers with thioethoxide ion in dimethyl formamide

✍ Scribed by G.I. Feutrill; R.N. Mirrington

Book ID
104248819
Publisher
Elsevier Science
Year
1970
Tongue
French
Weight
124 KB
Volume
11
Category
Article
ISSN
0040-4039

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✦ Synopsis

In connection with other work, we desired to demethylate a brcminated aryl methyl ether.

which also contained an acid-sensitive group elsewhere in the molecule.

The common acidic reagents (1,2) were obviously not applicable and, because Grignard reagents are of limited use in the presence of halogens (3). we turned our attention to cleavage by nucleophilic reagents according to the equation:

A survey of the literature for applications of this reaction was not encouraging.

Reagents "Y" such as hydroxide (1,4), methoxide (5), ethoxide (S), sulphite (B), thiophenoxide ( 7), and thioethoxide (a), each in protic solvents, have required the use of high temperatures, long reaction times, and sealed tube or autoclave conditions to effect even only partial demethylation in some oases. Sodium amidelpiperidine (9) (Y = piperidide ion), diphenylphosphide ion/THF (lo), and lithium iodidelcollidine (11) appeared more promising,

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