Ueber Diphenylen‐dioxyd

The Chemistry of the Diaryl Ethers.

“…Yields of 20-30 per cent may be obtained by the use of a large excess of phenoxide. In most cases the methyl ethers of the halogenated phenols are used instead, because of the higher yields of methoxydiphenyl ethers (286). Demethylation to the desired hydroxydiphenyl ethers is effected by heating with aluminum chloride in benzene (286), hydrobromic acid under pressure (269), hydriodic acid in acetic acid (174), or potassium hydroxide in ethylene glycol (293).…”

“…in good yield by heating with hydrobromic acid and a trace of red phosphorus at 190°C. (286). The dehydration may also be effected by heating with phosphorus oxychloride (286) or with zinc chloride (270).…”

“…(286). The dehydration may also be effected by heating with phosphorus oxychloride (286) or with zinc chloride (270).…”

Electrophilic substitution in highly substituted diphenyl ethers

“…4 Later, Bielig and Lützel reported that bromination and chloromethylation experiments with 2 resulted in the derivatives 5 and 6 which are substituted in the 4' position of the phenoxy ring. 5 The product obtained by chloromethylation was converted to an amino acid derivative of 1 which was reported to be 7, the structural analog of thyroxine in which all of the iodines have been replaced with methyl groups. This product has since been used in several biological studies designed to determine the effect of methyl relative to that of other substituents on the thyroxine nucleus.6 More recently, Van Heyningen has brominated 1 in acetic acid and reported the 4'-bromo derivative 8.7 8This product was converted by metal exchange and carbonation to a carboxylic acid.…”