Derivatives of Methyl N-[5(6)-(4-Aminophenylsulfanyl)benzimidazol-2-yl]carbamate and Phthalic Anhydrides. Synthesis and Biological Properties

Products of the reactions methyl N-[5(6)-(4-aminophenylsulfanyl)benzimidazol-2-yl]carbamate with phthalic anhydrides, involving the aniline nitrogen atoms, were obtained. Biological properties (embryotoxicity and toxicity) of the products and their mixtures with phase-transfer catalysts were studied. On this basis, new antihelminthic agents were developed.     

Regularities of the photodestruction of acridine dyes in aqueous media

Acridine dyes were found to exhibit a low light fastness in oxygen-containing aqueous solutions because of photooxidation with the participation of molecular oxygen. The values of the quantum yield for the photooxidation of Acridine Yellow, Acridine Orange, and proflavin acetate at their initial concentration 2 × 10^?5 mol/l were determined to be 1.8 × 10^?3, 1.5 × 10^?3, and 0.8 × 10^?3, respectively. It was concluded that the photooxidation of these acridine dyes in dilute solutions results in the formation of primary photoproducts of peroxide nature. For proflav in acetate, as an example, it was demonstrated that the increase of the substrate concentration to 6 × 10^?4 mol/l results in a fourfold increase in the quantum yield, a behavior indicative of a change in the photodecomposition mechanism. The rate of the interaction between exited and unexcited proflavin molecules, the process responsible for the photodecomposition of this compound, was found to be ～4 × 10⁷ l/(mol s). The quantum yield for the photooxidation of the proflavin base was estimated to exceed that for the photooxidation of the proflavin monocation by more than an order of magnitude.     

Interaction of phosphomolybdovanadium heteropolyacids with hydrazine hydrate studied by a calorimetric method

The heats of interaction of VO ₂ ⁺ and of heteropolyacids H_3+nPMo_12−nV_nO₄₀ (n=1,2,3,6) with N₂H₄ have been measured.

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Измерены теплоты взаимодействия VO ₂ ⁺ и гетерополикислот H_3+nPMo_12−nV_nO₄₀ (n=1,2,3,6) с N₂H₄.

     

Features of complexing of molecular NMR relaxation probes with cellulose acetates in solutions

The method of active and inert NMR relaxation probes can be used for determining the degree of substitution of cellulose acetates. The formation of hydrogen bonds between the hydroxyl and acetate groups of cellulose acetate is more probable than between the hydroxyl groups, which results in relative large shielding of the free OH groups in the polymer in samples with high degrees of substitution.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1761–1765, August, 1989.We would like to thank N. I. Naimark for providing the samples of the cellulose acetates.     

Nitration of 4-Acetylamino-4'-nitrodiphenyl Sulfide

Procedures have been developed for the acylation of 4-amino-4'-nitrodiphenyl sulfide with an almost quantitative yield by the action of acetic anhydride in aprotic organic solvents and subsequent nitration of 4-acetylamino-4'-nitrodiphenyl sulfide with nitric acid in a mixture of acetic acid and an aprotic organic solvent with addition of a mixture of sulfuric and acetic acids by the end of the process.     

Phenolic compounds of the plantGossypium hirsutum and of callus tissue from its anthers

The chemical composition of the catechins, leucoanthocyans, proanthocyanidins, and anthocyans of callus tissue ofGossypium hirsutum L. has been studied in comparison with cotton plants growing under natural conditions. From callus tissue of lines L-29, L-32, and L-35 we have isolated (+)-catechin, (±)-gallocatechin, (–)-epicatechin, cyanidin 3-O--D-glucopyranoside, and cyanidin 3-O-[O--D-xylopyranosyl-(14)--D-glucopyranoside]. It has been shown that the components of the phenolic complexes in the plant and in callus tissue differ qualitatively and quantitatively.A. S. Sadykov Institute of Biorganic Chemistry, Academy of Sciences, Tashkent, fax 62 70 71. Institute of Genetics of the Republic of Uzbekistan, Tashkent, fax (3712) 64 32 30. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 250–253, March–April, 1997.     

Synthesis and properties of derivatives of 2-mercaptobenzothiazole

2,3-Dihydro-4H-[1,3]-thlazino[2,3-b]benzothiazolium chlorides have been synthesized and their reduction with sodium borohydride has given previously-unknown derivatives of (perhydro-1,3-thiazino) [2,3-b]benzothiazoline. The stability of the compounds in acid and alkaline media has been studied.For part VII, see [1].     

Electrode Response of a Fluoride-Selective Electrode in Buffer Solutions of Potential-Determining Ions

The electrode response of a fluoride-selective electrode was studied in HNO₃ and Al(NO₃)₃ solutions of different concentrations and ionic strengths. We have substantiated the ion-exchange mechanism of the formation of fluoride ions in the near-membrane layer of blank buffer solutions and found that their concentration (⁰) was (4.0 ± 0.4) × 10^–6 M.     

Conducting and Photoactive Polymers on the Basis of Transition Metal Complexes: Electrochemical Synthesis

Mechanism of electrochemical oxidative polymerization and formation of polymers based on the transition metal complexes are considered. The complexes under study are assumed to have the resonance structures and a highly reactive imino group (–N=CH–) in the macrocyclic ring. IR spectra of the bis(salicylidene)ethylenediamine ligand (H₂Salen), [NiSalen] and [PdSalen] monomers, and the respective polymers are examined and used for the experimental substantiation of the proposed mechanism underlying the formation of conducting polymers.