Basicity of a Novel Macrocycle Containing Thiopyrimidine and Uracil Moieties in Various Water–Organic Mixtures

The acid–base behavior of the novel macrocycle, containing thiopyrimidine and uracil moieties 32-trimethyl-23,36-dioxo-15,19-dithio-2,9,13,20,24,31,34,35-octaazatatracyclo [28,3,1^10,14,1^20,24]hexatriacontaheptaen-1(34),10(35),11,13,21,30,32 (1) and the acyclic 1,6-bis[4-(N,N-dimethylamino)-6-methylpyrimidinile-2-thio]hexane (2) were studied by potentiometric, UV-Vis, ¹H, NMR spectroscopic methods in water–dimethyl sulfoxide (methanol, 1,4-dioxane) solutions and at the interface between water and chloroform phases. The data obtained indicate, that thiopyrimidine nitrogens are the protonation sites of both 1 and 2. The protonation of 2 occurs in one step, while 1 is protonated stepwise in the pH range 9–2.5. The NMR data indicate that the intramolecular interaction between protonated pyrimidine and uracil moieties is the main reason for the stabilization of protonated forms of 1. The protonation constants of 1 were found to be different in various water–organic mixtures, which is in accord with the different ¹H NMR spectra of 1 in various solvents. The protonation of 1 at the water–organic phase boundary is effected by the extraction of [1·2H]²⁺ into the aqueous phase, which can be regarded as a way of obtaining its water -soluble form.     

Intermolecular interactions of tetraanions of macrocyclic tetraresorcinol in H2O—DMF solutions

According to the data of pH-metric titration, macrocyclic tetraresorcinol (1c) dissociates stepwise with the abstraction of one, two, and four protons. Aggregation of tetraanions of 1c in H₂O-DMF solutions was detected by conductometry. The degree of aggregation increases as the size of the counterion decreases and the content of DMF in the solvent mixture increases.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1171–1174, May, 1996.     

Mannich Reaction as a Convenient Route to New Macrocyclic Compounds Containing an Uracil Fragment

Mannich reaction of 1,3-bis[4-(2-mercaptomethylphenoxy)butyl]-6-methyl-1,2,3,4-tetrahydropyrimidine-2,4-dione, formaldehyde, and N-benzylamine afforded a 24-membered macrocyclic compound containing an uracil fragment, 1,3-(11-benzyl-6,7:15,16-dibenzo-5,17-dioxa-9,13-dithia-11-aza-6,15-heneicosadiene-1,21-diyl)-6-methyl-1,2,3,4-tetrahydropyrimidine-2,4-dione.     

Two-fragment α-adrenolytics. 4. Synthesis of phosphorylated derivatives of 2-aryloxyethylamines and N-phenylpiperazine

The reactions of 3-chloropropylphosphonates, 3-chloropropylthiophosphonates, or 3-chloropropylphosphinates with 2-aryloxyethylamines or N-phenylpiperazine afford the corresponding 3-(2-aryloxyethylamino)propylphosphonates and -phosphinates or 3-(4-phenylpiperazin-1-yl)propylphosphonates and -phosphinates. The compounds obtained exhibit -adrenolytic and hypotensive activities, the latter being found to depend on the substituents at the P atom.     

Near-field effect in thermal radio-frequency radiation

The near-field effect was experimentally observed in the thermal radiation of an absorbing medium in the rf range. The radiation from a temperature-stratified aqueous medium was measured at a wavelength of 31 cm using specially developed electrically small antennas. The effect manifests itself as a decrease in the effective thickness of a layer in which the received radiation is formed and in the dependence of this thickness on the receiving antenna’s size and its height above the medium surface.     

Intermodulation in a microwave resonator with a high-temperature superconductor

Intermodulation, or the generation of a combination-frequency signal, is studied theoretically in the case where the nonlinearity is provided by a high-temperature superconductor placed in a microwave resonator. A general formula that relates the power of an intermodulation signal to the electromagnetic performance of the resonator, the physical parameters of the superconductor, and the intensity of pump waves is derived. A parameter that characterizes the nonlinearity is evaluated from data available from the literature. The potentialities of various resonators for the microwave characterization of the nonlinearities in high-temperature superconductors are assessed.     

The role of secondary reggeons in central meson production

We estimate the contribution of f₂ trajectory exchange to the central and production. It is shown that secondary reggeons may give a large contribution to processes of double diffractive meson production at high energies. Received: 10 May 2000 / Accepted: 4 June 2000     

Amphiphilic pyrimidinophane,a new dimeric surfactant: Synthesis,aggregation, and catalytic activity

Abstract Tensiometry, conductometry, dynamic light scattering, and potentiometry are used to study the aggregation of a new amphiphilic alkylated pyrimidinophane (APP) in aqueous solutions in the presence of polyethylen-imine. The new geminal surfactant is shown to possess high micellization ability (CMC = 0.00001 M) due to the presence of an additional alkyl radical in the pyrimidine fragment. APP aggregates are characterized by a low degree of counterion binding (lower than 50%). Spectrophotometry is employed to investigate the catalytic activities of individual surfactant solutions and solutions of APP—polyethylenimine binary mixtures with respect to the hydrolysis of phosphonic acid esters. The effect of APP on phosphonate hydrolysis is typical of cationic surfactants. The higher acceleration is observed for the hydrolysis of a more hydrophobic phophonate.     

Synthesis of Some 1-Alkyl 3,5-Bis(ω-haloalkyl) Isocyanurates

1-Methyl or 1-benzyl 3,5-bis(-bromoalkyl) isocyanurates with the alkyl chain comprising 3 through 6 methylene units were synthesized by the reaction of disodium methyl and benzyl isocyanurates with ,-dibromoalkanes. The reaction of disodium methyl and benzyl isocyanurates with ethylene chlorohydrin was used to obtain 1-methyl or 1-benzyl 3,5-bis(2-hydroxyethyl) isocyanurates whose treatment with PBr3 or SOCl2 gave the corresponding 1-alkyl 3,5-bis(2-haloethyl) isocyanurates. 1-Methyl and 1-benzyl 3,5-bis-(chloromethyl) isocyanurates were prepared by treatment with SOCl₂ of 1-methyl or 1-benzyl 3,5-bis(hydroxymethyl) isocyanurates obtained, in their turn, by condensation of methyl and benzyl isocyanurates with formaldehyde.