Abstract
Coumarin derivatives were easily prepared starting from 7-hydroxy 4-methyl-2H-chromen-2-one with 40% formaldehyde and suitable secondary amines in 95% ethanol in rather good yield. The structures of all compounds were confirmed via spectroscopic techniques IR, 1H NMR, 13C NMR, mass spectra and elemental analysis. The complexing properties of the coumarin derivatives toward alkali metal, alkaline earth metal, some transition metals and some heavy metal cations have been investigated in methanol by means of UV spectrophotometry absorption and conductivity methods. Thus, the stoichiometry of the complexes formed and their stability constants were determined.
Highlights
While the Mannich reaction is an organic reaction used to convert a primary or secondary amine and two carbonyl compounds to a β-amino carbonyl compound, known as a Mannich base, using an acid or base catalyst, in a variant of the reaction the enolizable carbonyl component can be replaced with an electronrich aromatic system, which is called an aminomethylation of an arene
Efforts to quantify the complexation equilibrium were based on the use of UV spectrophotometry, conductometric measurements were used to obtain preliminary estimates of the stoichiometry of complexes formed
Complexation of metal cations in methanol The logarithms of the stability constants log βxy and the stoichiometries of the different complexes formed by compounds [2, 3] and 5 with alkali metals, alkaline-earth metals and some transition metals in methanol are given in Tables 1 and 2
Summary
While the Mannich reaction is an organic reaction used to convert a primary or secondary amine and two carbonyl compounds (one non-enolizable and one enolizable) to a β-amino carbonyl compound, known as a Mannich base, using an acid or base catalyst, in a variant of the reaction the enolizable carbonyl component can be replaced with an electronrich aromatic system, which is called an aminomethylation of an arene. Their complexation of alkali metal, alkaline earth metal and transition metal cations, and the liquid liquid extraction of metallic picrate salts by coumarin derivatives [2, 3] and 5 were investigated, . The Mannich bases [2,3] were prepared starting from 7-hydroxy 4-methyl-2H-chromen2-one 1 with 40% formaldehyde and suitable secondary amines in 95% ethanol in rather good yield[22] (Scheme 1).
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