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Continuous N-alkylation reactions of amino alcohols using γ-Al₂O₃ and supercritical CO₂: unexpected formation of cyclic ureas and urethanes by reaction with CO₂.

ABSTRACT: The use of γ-Al₂O₃ as a heterogeneous catalyst in scCO₂ has been successfully applied to the amination of alcohols for the synthesis of N-alkylated heterocycles. The optimal reaction conditions (temperature and substrate flow rate) were determined using an automated self-optimising reactor, resulting in moderate to high yields of the target products. Carrying out the reaction in scCO₂ was shown to be beneficial, as higher yields were obtained in the presence of CO₂ than in its absence. A surprising discovery is that, in addition to cyclic amines, cyclic ureas and urethanes could be synthesised by incorporation of CO₂ from the supercritical solvent into the product.

SUBMITTER: Streng ES

PROVIDER: S-EPMC5331277 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Continuous N-alkylation reactions of amino alcohols using γ-Al2O3 and supercritical CO2: unexpected formation of cyclic ureas and urethanes by reaction with CO2.

Streng Emilia S ES Lee Darren S DS George Michael W MW Poliakoff Martyn M

Beilstein journal of organic chemistry 20170221

The use of γ-Al2O3 as a heterogeneous catalyst in scCO2 has been successfully applied to the amination of alcohols for the synthesis of N-alkylated heterocycles. The optimal reaction conditions (temperature and substrate flow rate) were determined using an automated self-optimising reactor, resulting in moderate to high yields of the target products. Carrying out the reaction in scCO2 was shown to be beneficial, as higher yields were obtained in ...[more]

PMID: 28326142

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