256. Phthalic esters as alkylating agents

King, Harold; Wright, Emily

doi:10.1039/jr9390001168

Cited by 6 publications

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“…In 1939, King and Wright described the synthesis of anisole from equimolar quantities of potassium phenolate and methyl benzoate or dimethyl phthalate at temperatures of 180−200 °C under pressure:…”

Section: Williamson Ether Synthesis Using Weak Alkylating Agentsmentioning

confidence: 99%

Synthesis of Alkyl Aryl Ethers by Catalytic Williamson Ether Synthesis with Weak Alkylation Agents

Fuhrmann

Talbiersky

2005

Org. Process Res. Dev.

140

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For almost 70 years, there have been attempts to advance the Williamson ether synthesis process to allow the use of low-cost, noncarcinogenic, weak alkylating agents and avoid salt production. These attempts to produce a "green" version of Williamson ether synthesis have been based on the use of weak alkylating agents such as carboxylic acid esters at relatively high temperatures (approximately 200 °C) and pressures. However, none of the processes considered was suitable for industrial application because of the high concentration of the alkali metal carboxylates required. By increasing the temperature to above 300 °C, it has now proved possible to carry out Williamson ether synthesis as a homogeneous catalytic process. The large temperature increase significantly boosts the alkylating power of weak alkylating agents such as alcohols, carboxylic acid esters, and ethers derived from weak Bro 1nsted acids, which are only weak alkylating agents at room temperature. At such temperatures, carboxylic acid esters such as benzoic acid methyl ester or acetic acid methyl ester demonstrate the alkylating power usually expected of alkylating agents derived from strong acids. In the catalytic cycle of this new process, for example, the low-cost alcohol methanol and phenol were converted into anisole and water at 320 °C via the intermediate methyl benzoate in the presence of catalytic quantities of alkali metal benzoate and phenolate. The catalytic Williamson ether synthesis (CWES) at high temperatures is especially well-suited for the production of alkyl aryl ethers such as anisole, neroline, and 4-methyl anisole which are of industrial importance. Selectivity values of up to 99% have been reached.

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Section: Williamson Ether Synthesis Using Weak Alkylating Agentsmentioning

confidence: 99%

Synthesis of Alkyl Aryl Ethers by Catalytic Williamson Ether Synthesis with Weak Alkylation Agents

Fuhrmann

Talbiersky

2005

Org. Process Res. Dev.

140

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show abstract

“…and the rearrangement of benzyl and related ethers with strong bases such as phenyllithium3 or potassium amide. 4 The usefulness of these reactions has been limited, however, by their rather specialized structural requirements and, in examples of the second type, because of the necessity for the use of highly active (and therefore non-selective) reagents and, often, rather severe conditions.…”

mentioning

confidence: 99%

Cleavage and Rearrangement of Ethers with Bases. III. Ethers of Benzoin and Ethyl Mandelate^1a

Curtin¹,

Proops²

1954

J. Am. Chem. Soc.

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Macdonald¹,

Lingard²

1993

Dictionary of Analytical Reagents

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256. Phthalic esters as alkylating agents

Cited by 6 publications

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Synthesis of Alkyl Aryl Ethers by Catalytic Williamson Ether Synthesis with Weak Alkylation Agents

Synthesis of Alkyl Aryl Ethers by Catalytic Williamson Ether Synthesis with Weak Alkylation Agents

Cleavage and Rearrangement of Ethers with Bases. III. Ethers of Benzoin and Ethyl Mandelate^1a

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256. Phthalic esters as alkylating agents

Cited by 6 publications

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Synthesis of Alkyl Aryl Ethers by Catalytic Williamson Ether Synthesis with Weak Alkylation Agents

Synthesis of Alkyl Aryl Ethers by Catalytic Williamson Ether Synthesis with Weak Alkylation Agents

Cleavage and Rearrangement of Ethers with Bases. III. Ethers of Benzoin and Ethyl Mandelate1a

D

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Cleavage and Rearrangement of Ethers with Bases. III. Ethers of Benzoin and Ethyl Mandelate^1a