Tetracyclines Communication 21. Synthesis of 2- and 3-substituted 10-oxo-9-hydroxy-9-methyl-1,2,3,4,4a,9,9a,10-octahydroanthracenes

Summary Various 10-oxo-9-hydroxy-9-methy 1-1,2,3,4,4a,9,9a,10-octahydroanthracenes were synthesized; they are analogous in structure to the DCB ring system of tetracyclines and have active functional groups in the 2- and 3-positions (halogen atoms, the epoxy group, hydroxyl, and ketonic carbonyl), which creates the potentiality of the further introduction of suitable substituents and then the building up of the fourth ring of tetracyclines.For communication 20 see [1].The authors are deeply indebted to L. B. Senyavina for the measurement of infrared spectra.Translated from Izvestiya Akademii Nauk SSSR, Setiya Khimicheskaya, No. 6, pp. 1013–1024, June, 1964     

Tetracyclines

Summary As a result of a spectropolarimetric comparison of the phthalidecarboxylic products (IIIa) and (IIIb)of the degradation of aureomycin with specially synthesized 3S-(-)-3-methyl-3-phthalidecarboxylic acid (IV), the absolute configuration (I) was proved for tetracycline and 7-halotetracyclines and was postulated for 5-hydroxy- and 6-de-methyl- tetracyclines.For Communications 13–15 see [1-3].     

Investigation of inclusive production ofK 0 andK * (892)0 mesons inK + A interactions at 11.2 GeV

Inclusive production ofK ⁰ andK ^* (892)⁰ mesons inK ⁺ A-interactions (A=Be, Cu, Pb) at the energy 11.2 GeV has been investigated to study hadronisation of the leading \(\bar s\) -quark; the results are presented. Double differential cross sections d²σ/dx _f dp _t ² were measured in the region of incident particle fragmentation (0.4≦x _f ≦1,p _t ≦0.5 GeV/c). The experimental data obtained were analysed on the basis of the Lund model FRITIOF and a quark-gluon model that takes into account colour screening and hadron formation length effects. The experimental data confirm the picture of hadronisation of the leading \(\bar s\) -quark developed in the latter model.     

Dependence of characteristics of tantalum powders on the type of the extractant used in preparation of raw material

The effect exerted by different extractants (cyclohexanone, dimethylamides of carboxylic acids C₁₀-C₁₃, and octanol-1), which are used for preparation of potassium heptafl uorotantalate, on its purity and characteristics of sodium-reduced tantalum powders was studied experimentally.     

Diffusion Coating of Nickel with Tantalum in Chloride-Fluorotantalate Melts

The effect of temperature and time on the diffusion saturation of nickel with tantalum in molten salt mixture NaCl-14 mol % K₂TaF₇ in the presence of metallic tantalum powder was studied, and characteristics of the obtained diffusion coatings were analyzed.     

Combined TEM-AFM study of “transrotational” spherulites growing in thin amorphous films

“Transrotational” Se and α-Fe₂O₃ spherulites have been investigated by transmission electron microscopy and atomic force microscopy. Combination of these two microscopic methods made it possible to reveal structural peculiarities and the character of the spherulite surface, as well as to compare these data. It is established that, along with the regularly changing lattice orientation at the crystallization front, there is a regular relief of the crystal surface. Inheritance of the globular structure of the amorphous matrix by a growing crystal is revealed. In this case, the structure remains homogeneous, independent of the differences in the lattice orientation and imperfection of the regions crystallized.     

Determination of the recombination parameters of a semiconducting material by the Prony method

A generalized Prony method is used to process experimental data of the relaxation type. The method can be used to separate a compound relaxation process into elementary components (damped exponentials) and to systematically trace the variation of their parameters in the presence of external excitation, thereby opening additional channels of information on the generating physical process. The method is applied to the processing of photoconductivity decay data for complex-doped, compensated silicon in the temperature range 100–300 K after pulsed excitation by laser radiation with λ=1.06 μm in a microwave field. The position of the energy level is obtained as 0.17±0.01 eV, in good agreement with the energy of the oxygen-vacancy complex. Zh. Tekh. Fiz. 69, 54–59 (April 1999)     

Synthesis of 2,5,7‐Triaryl‐4,7(6,7)‐dihydropyrazolo[1,5‐a]pyrimidine‐3‐carbonitriles by Reaction of 5(3)‐Amino‐3(5)‐aryl‐1H‐pyrazole‐4‐carbonitriles with Chalcones

The reaction of 5(3)‐amino‐3(5)‐aryl‐1H‐pyrazole‐4‐carbonitriles with 1,3‐diaryl‐2‐propen‐1‐ones (chalcones) in refluxing DMF leads to 2,5,7‐triaryl‐4,7(6,7)‐dihydropyrazolo[1,5‐a]pyrimidine‐3‐carbonitriles. In DMSO solution, the latter exist in equilibrium of two tautomeric 4,7‐dihydropyrazolo[1,5‐a]pyrimidines and 6,7‐dihydropyrazolo[1,5‐a]pyrimidines in various ratios, depending on the nature of aryl substituents in chalcone building blocks.