- Regioselective iodination of tyrosine in a liquid membrane system, in the presence of crown ether type macrocyclic ligands. I obtention of monoiodotyrosine
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The experiments performed have shown that, when using a "liquid membrane" system (aqueous phase source containing KI + I2 K+I3-, the receiving aqueous phase containing tyrosine, the "liquid membrane" being represented by dichloroethane, which contains the crown ether CE =18-crown-6), the selective iodination of tyrosine can be controlled so as to obtain, after four hours, monoiodotyrosine with a 100% yield.
- Luca, Constantin,Zarna, Adriana,Anghel, Dan,Constantinescu, Titus
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p. 125 - 130
(2007/10/03)
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- Regioselective iodination of tyrosine in a liquid membrane system in the presence of crown ether type, macrocyclic ligands. II: The factors which influence regioselective iodination
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The regioselective iodination of tyrosine 1 in a "liquid membrane" system - aqueous phase source/dichloroethane/aqueous receiving phase - in view of obtaining preferentially, first, monoiododerivative 2 and then diiododerivative 3 is controlled by the exclusive existence in the "liquid membrane" of the complex species [CE?I]+I3- (with no free I2). The highest yield (100%) of derivative 2 is obtained when CE=18-crown-6. The process is considered to be of the electophilic aromatic substitution type (through "phase transfer catalysis") the experiments suggesting that the reactive iodine species results from the [CE?I]+I3- complex decomposition at the "membrane"/receiving aqueous phase (containing tyrosine) interface.
- Luca, Constantin,Zarnǎ, Adriana,Anghel, Dan,Constantinescu, Titus
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p. 601 - 608
(2007/10/03)
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