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Two-phase potentiometric titration was used to determine partition constants for a series of a-aminophosphonates (RO) 2 P(O)CH 2 NR 1 R 2 [R = Alk (C 2 3C 5 ), R 1 , R 2 = Me, Et, (CH 2 ) 5 ] between water and organic solvents, such as chloroform, carbon tetrachloride, toluene, octane, n-octanol, nitrobenzene, o-xylene, and cyclohexane. Correlations between the partition constants and the number of carbon atoms in substrate molecules were obtained. Solvent effects on partition constants were discussed, and solution parameters of a-aminophosphonates were calculated.The fast recent progress of the chemistry of aminophosphoryl compounds is primarily connected with their extensive practical use. Being structural analogs of proteinogenic amino acids, they proved to be highly effective biologically active compounds with a broad-spectrum activity [133].Though the biological activity of aminophosphosphoryl compounds is a very attractive feature, some other field of practical use of this type of phosphorus compounds have recently been recognized. Among a-aminophosphonates, highly effective extractants, complex-forming agents, membrane transporters, ionophores, and some other reagents whose activity is based on the complex-forming ability of aminophosphonates have been found [1].Previously we described [438] methods of synthesis of new compounds containing one or two aaminophosphoryl groups, studied their acid3base properties, and demonstrated their use for extraction and analysis of metal ions. Extractive properties of these compounds present undoubted interest for searching new highly effective analytical and transport reagents. The possibility of wide variation of the nature of substituents at the reaction centers of the alkylaminophosphoryl skeleton of these compounds. i.e. phosphorus, a-carbon, and nitrogen, renders them promising objects for research into the effect of structural factors on extractive and other important properties.At the same time, of great importance for studying mechanisms of liquid-phase and membrane extraction, developing technology of purification of aminophosphonates, and predicting their biological activity are quantitative data on the behavior of these compounds in two-phase aqueous3organic solvent systems.In this connection we set ourselves the aim to determine the partition constants of aminophosphonates containing alkyl and heterocyclic (piperidyl) fragments, in two-phase systems comprising water and organic solvents of different nature.Aminophosphonates I3IX were prepared by Kabachnik3Fields reaction [1] in a ternary system comprising a dialkyl hydrogen phosphite, formaldehyde, and a carbonyl compound. Characteristics of newly synthesized phosphonates are presented in [5]. E I!IXR 1 = n-Pr, R 2 = R 3 = Me (I); R 1 = n-Bu, R 2 = R 3 = Me (II); R 1 = Et, R 2 = R 3 = Et (III); R 1 = n-Pr, R 2 = R 3 = Et (IV); R 1 = n-Bu, R 2 = R 3 = Et (V); R 1 = Et, R 2 + R 3 = (CH 2 ) 5 (VI); R 1 = n-Pr, R 2 + R 3 = (CH 2 ) 5 (VII); R 1 = i-Pr, R 2 + R 3 = (CH 2 ) 5 (VIII); R 1 = Et, R 2 = CH(CH 3 ) 2 , R...

New and previously known -aminoethylphosphonates were synthesized by addition of primary and secondary amines to vinylphosphonates, and their IR and NMR spectra were examined. Diethyl 2-diethylaminoethylphosphonate and diethyl 2-morpholinoethylphosphonate were found to be stronger bases than the corresponding aminomethylphosphonates, but all these are weaker bases than their precursors, nonphosphorylated amines. Distribution constants of -aminophosphonates between water and some organic solvents were determined and compared with those of their -amino homologs.In the series of our preceding publications we described methods of synthesis and acid-base properties of a large number of -aminophosphoryl compounds [1] which can be regarded as phosphorus-containing analogs of natural amino acids. In the recent years, these compounds attract attention of researchers working in the fields of not only fine organic synthesis and chemistry of biologically active substances but also related sciences, such as biochemistry, pharmacology, medicine, agricultural chemistry, etc. [2, 3]. Apart from high efficiency as bioactive substances, -aminophosphoryl compounds were shown to be capable of forming complexes with various species, including metal ions, organic and inorganic acids, etc. [4,5]. In particular, we studied -aminophosphonates as extractants which ensured selective separation of noble metal ions from concomitant elements [6]. Variation of substituents at the phosphorus, -carbon, and nitrogen atoms over a wide range showed that the most selective extractants were those aminophosphoryl reagents which contained more than 20 carbon atoms; in this case, the optimal hydrophilic-lipophilic balance was achieved. It should be emphasized specially that the above information was deduced by analysis of correlations between the number of carbon atoms in the extractant molecules and their distribution constants in waterorganic solvent systems [7]. Therefore, the latter parameter is necessary to elucidate the structure-property relations with a view to effect subsequent purposeful synthesis of extractants, bioactive, and other potentially useful substances possessing an optimal combination of the desired characteristics.The present article opens a series of publications on the synthesis and study of extracting, membranetransfer, and ionophoric properties of a new class of phosphorus-and-nitrogen-containing complexing agents, -aminophosphoryl compounds. Here, we report on the synthesis, acid-base properties, and distribution constants in two-phase aqueous-organic systems of a series of previously described and new -aminophosphonates. When possible, the parameters under study were compared with the data for their analogs, -aminophosphonates, and precursors, the corresponding amines. We believe that such analysis is useful for estimation of factors responsible for physiological and complexing properties of the compounds under study.Properties of -phosphorylated amines have been studied to a considerably lesser extent, as compared to their ...

Structural thermodynamic analysis of the acidity of a-aminophosphoryl compounds in water3isopropanol systems was carried out by means of evaluation of the Gibbs energies of transfer of species involved in protolytic equilibria. Protonated (deprotonated) forms of structurally diverse aminophosphoryl compounds similarly interact by the mechanism of specific and universal solvation with each of the water3 isopropanol solvents (100, 50, and 25 vol % of water) in the reaction series used. For this reason, there are significant linear correlations between acidity parameters for various media, which makes possible successful predictions of the acid3base properties of structurally diverse compounds of the class studied in water3iso-propanol media with various water contents.We previously studied the acid3base properties of a series of a-aminophosphoryl compounds in the water3 ethanol medium and revealed certain structure3 basicity relationships. Specifically, it was found that variation of substituents on phosphorus, nitrogen, and carbon only slightly affects the basicity of phosphorylated amines, and the pK a values of their conjugate acids are 536 units lower than values characteristic of their precursors, nonphosphorylated amines [1]. Since we previously evaluated pK a values for a broad range of aminophosphoryl compounds in water3isopropanol media with varied component ratios, in the present work we considered it necessary to express quantitatively the effect of the medium on the dissociation constants. It is known that the ionization constants of structurally related compounds in various media are linearly related to each other, and establishment of such linear correlations makes possible prediction of the ionization constants of aminophosphoryl compounds in mixed solvents. However, such approach is correct only when the linear free energy principle is fulfilled for interactions of the participants of acid3 base equilibria and the medium.Dissociation constants can be measured in water, as well as in other solvents or in their aqueous solutions. As organic compounds are generally sparingly soluble in water, their pK a values are measured in aqueous-organic media containing a significant fraction of the organic solvent, such as DMF, 2-methoxyethanol, and some other water-miscible compounds solvents. Lower alcohols (C 1 3C 3 ) are most often used for this purpose [235].It is commonly accepted that the pK a values of acids in alcohol-containing media linearly vary with the dielectric constant of the mixed solvent [637]. Hydrophobic solvation effects can also take place [8]. They give rise to extrema in organic-poor parts of composition3property plots for aqueous-organic media.Solvent is an important outer variable, since alteration of its nature and composition means, in essence, shift of the equilibrium. In terms of thermodynamics, this means transformation of the energy of the initial and final states of the system due to alteration of the solvation state of the components involved in the equilibrium [10312]. Solvent ...

Organo-phosphorus compounds S 0080 Synthesis of β-Aminophosphonates and Study of Their Acid-Base Properties and Phase Distribution in Water-Organic Solvent Systems. -Aminophosphonates (III) are generally obtained in high yields. In the case of derivative (IIIc) containing a long alkyl chain, the yield is only low. -(CHERKASOV*, R. A.; GALKIN, V. I.; KHUSAINOVA, N. G.; MOSTOVAYA, O. A.; GARIFZYANOV, A. R.; NURIAZDANOVA, G. K.; KRASNOVA, N. S.; BERDNIKOV, E. A.; Russ. J. Org.