Pyrido[2,3-d]dipyrimidines 8. Synthesis of pyrrolo(2′,3′∶4,5)pyrido[2,3-d]pyrimidines

The reaction of 1,3-dimethyl-5-chloro-6-nitropyrido[2,3-d]pyrimidine-2,4-dione with CH-acids yielded 5-substituted pyridol[2,3-d]pyrimidines which were used in the synthesis of pyrrolo(2,34,5)pyrido[2,3-d]pyrimidines.For Communication 7, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 800–803, June, 1993.     

The lignin of the sea island cotton plant of variety S-6030 affected by fusarial wilt. I

A comparative study of the dioxane lignins isolated from healthy and wilt-affected cotton plant stems has shown thatFusarium fungi demethylate lignin and make it more oxidized than the lignin from healthy stems.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 825–827, November–December, 1985.     

The effect of nanosized titania-silica film composition on the photostability of adsorbed methylene blue dye

The effect of nanosized porous films (average density 10 g/m²) of TiO₂. TiO₂/SiO₂, and SiO₂ on the photostability of adsorbed methylene blue (MB) dye during UV irradiation in air was investigated by optical spectroscopy and laser-induced mass spectrometry. The effectiveness of the photodecomposition of MB decreases in the order TiO₂ > TiO₂/SiO₂ > SiO₂ with rate constants 1E-2, 0.6E-2, and 0.3E-2 min⁻¹ respectively. A mechanism including the participation of both excited states of the dye molecules and photoexcited titanium dioxide is proposed for the photodecolorization of MB adsorbed on the surface of the investigated films. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 43, No. 4, pp. 220–225, July–August, 2007.     

Sensing Element of a Benzopurpurin 4B-Based Optical Sensor for Determining the Acidity of Etch Solutions

Deposition conditions are studied, and a Langmuir–Blodgett film (LBF) based on the benzopurpurin 4B indicator immobilized in the polyamide acid salt matrix is obtained. The protolytic properties of the indicator are studied in water, micelles of cationic and nonionic surfactants, and LBFs. It is shown that, in going from water to the cited micelles and LBFs, pK _ind is shifted to the acidic region by 3.25, 1.18, and 2.30 pH units, respectively. The possibility of using the produced LBF as the sensing element of an optical sensor for the determination of the acidity of solutions in the pH range 1–0 is demonstrated. The LBF is applied to the determination of the acidity of solutions in etch baths. The response time in the operating range is 10–20 s; the standard deviation is no more than 4%.     

New acylated flavone glycoside fromGnaphalium uliginosum

A new acylated flavone glycoside has been isolated for the first time from the herb marsh cudweed, and for it the structure of 6-caffeyl-7--D-glucopyranosyloxy-4,5-dihydroxy-3,6dimethoxyflavone has been established. In addition, the aglycone, identified as 4,5,7-trihydroxy-3,6-dimethoxyflavone has been isolated. The identifications were made on the basis of UV, IR, PMR, and mass spectra, the products of alkaline and acid hydrolyses, and the results of elementary analysis, melting points, and specific rotations.Vitebsk Medical Institute. All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 311–315, May–June, 1979.     

Study of the formation of polyimide from complexes of benzophenonetetracarboxylic acid diester with different diamines. 2. Features of thermal imidization of the molecular complex of benzophenonetetracarboxylic acid diester with 2,6-diaminopyridine

H-bond complexes of benzophenonetetracarboxylic acid dimethyl ester with 2,6-diaminopyridine (BZPE·DAP) have a dimeric structure in which one of the amino groups of the diaminopyridine participates in the formation of an H bond and the other does not form strong intermolecular bonds. During thermal imidization, the relative reactivity of the free amino group is lower than the reactivity of the group bound in the complex. In the BZPE·DAP system, 10% of the free amino groups remain after completion of imidization and they disappear at a high temperature. It is hypothesized that they can participate in the formation of interchain imide bonds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 530–533, March, 1990.     

Synthesis and reactions of esters of 3-cyano-2-OXO-5,6-tri(tetra)methylene-1,2-dihydroisonicotinic and 2-amino-3-Ethoxycarbonyl-5,6-tri(tetra)-methyleneisonicotinic acids

Esters of 3-cyano-2-oxo-5, 6-tri (tetra)-methylene-1, 2-dihydroisonicotinic and 2-amino-3-ethoxycarbonyl-5, 6-tri (tetra)methyleneisorticotinic acids have been obtained by the reaction of 2-oxocyclopentyl(hexyl)glyoxylic acid esters with malonic acid derivatives. Boiling the esters containing a tetramethylene ring with 75% sulfuric acid gave hydrolysis of the ester and cyano groups to carboxyl with subsequent decarboxylation at the 3 position and the formation of 2-oxo-5, 6-tetramethylene-1, 2-dihydroisonicotinic acid (2-oxo-1, 2, 5, 6, 7, 8-hexahydroquinoline-4-carboxylic acid).Perm Pharmaceutical Institute, Perm, 614000. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 370–373, March, 1996. Original article submitted July 10, 1995, revision submitted December 26, 1995.     

Possible Shubnikov's formulas of chemical compounds

M. V. Lomonosov Moscow State University. Translated fromZhumal Struktumoi Khimii, Vol. 36, No. 4, pp. 760–763, July–August, 1995     

Thermodynamics of phenylated polyphenylene between 0 and 340 K

In an adiabatic vacuum calorimeter, the temperature dependence of the heat capacity C _p of phenylated polyphenylene and initial comonomer 1,4-bis(2,4,5-triphenylcyclopentadienone-3-yl)benzene was studied between 6 and 340 K with an uncertainty of about 0.2%. In a calorimeter with a static bomb and an isothermal shield their energies of combustion DUcomb were measured. From the experimental data, the thermodynamic functions C _p ⁰ (T), H ⁰(T)-H ⁰(0), S ⁰(T)-S⁰(0), G ⁰(T)-H ⁰(0) were calculated from 0 to 340 K, and standard enthalpies of combustion ΔH _comb ⁰ and thermodynamic parameters of formation-enthalpies ΔH _f ⁰, entropies ΔH _f ⁰, Gibbs functions ΔG _f ⁰ - of the substances studied were estimated at T=298.15 K at standard pressure. The results were used to calculate the thermodynamic characteristics (ΔH _f ⁰ ,ΔS _f ⁰, ΔG _f ⁰) of phenylated polyphenylene synthesis in the range from 0 to 340 K. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermodynamics of dimethylene urethane and poly(dimethylene urethane) in the range from T → 0 to 490 K at standard pressure

By high-precision dynamic calorimetry the temperature dependences of heat capacity of dimethylene urethane (DMU) between 320 and 370 K and partially crystalline poly(dimethylene urethane) (PDMU) in the range 326-490 K at standard pressure have been determined within ±1.5%. The thermodynamic characteristics of fusion of the substances, namely the temperature interval of melting, temperature, enthalpy and entropy of fusion, as well as the characteristics of devitrification and glassy state for poly(dimethylene urethane) have been estimated. The first and the second cryoscopic constants have been calculated for dimethylene urethane. The experimental data obtained in the present work and literature findings on the heat capacity of the substances were used to calculate their thermodynamic functions: the heat capacity C°_p (T), enthalpy H°(T)−H°(0), entropy S°(T) and Gibbs function G°(T)−H°(0) over the range from T→0 to (370-480) K. Based on the data, the thermodynamic characteristics of polymerization process with five-membered ring opening Δ_polH°, Δ_polS° and Δ_polG° of dimethylene urethane with the formation of linear partially crystalline poly(dimethylene urethane) have been evaluated.