Synthesis of 2α,3β- and 2β,3β-caranediols

Conclusions 2,3- and 2,3-caranediols were synthesized by the oxymercuration-demercuration of 3-carene- and 3(7)-caren-2-trans-ols with successive reduction of 3,4-epoxycaran-2-one with KBH₄, and LiAlH₄, respectively.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1294–1298, June, 1979.     

A Zinc-Selective Electrode with a Low Detection Limit and Its Use in the Analysis of Environmental Samples

The analytical characteristics of a tetrathiocyanozincate ion-selective film electrode were studied. The electrode membrane was based on the specially synthesized highly lipophilic [(CH₃)₃N(C₄₃H₇₉O₃)]₂Zn(SCN)₄ ion exchanger, which served as an ionophore. It was shown that this electrode can be used for determining zinc(II) in environmental samples at the level lower than its maximum permissible concentration (MPC).     

Condensation of 2-Alkylcyclohexane-1,3-diones with Cyclic Azomethines

Reaction of 2-acylcyclohexane-1,3-diones with 5- and 6-membered cyclic azomethines (3,4-dihydro-2H-pyrrole and 2,3,4,5-tetrahydropyridine) furnished derivatives of 2,3,3a;,4,8,9-hexahydropyrrolo[1,2-a]quinoline-5,6(1H,5aH)-dione and 3,4,4a,5,9,10-hexahydro-1H-pyrido[1,2-a]quinoline-6,7(2H,8H)-dione respectively. In reaction with 7-membered 3,4,5,6-tetrahydro-2H-azepine we failed to isolate polycyclic nitrogen-containing products.     

Characterization of vacancy-related defects introduced into silicon during heat treatment by deep-level transient spectroscopy and gamma-ray diffraction techniques

Vacancy-related defects introduced into n-Si during annealing or aluminium diffusion at high temperature (1000–1250°C) have been studied. Different ambients (argon, nitrogen, vacuum and chlorine-containing atmosphere) were used to create a vacancy supersaturation during heat treatments. Three deep-level centers whose formation is governed by the presence of vacancies have been identified. They were characterized by the following temperature dependences of the thermal emission rate:e3 = 7.92 × 10⁷ T ² × exp(– 0.455/kT),e ₅ = 2.64 × 10⁶ T ² × exp( – 0.266/kT),e ₇ = 7.26 × 10⁶ T ² × exp (– 0.192/kT). The influence of different factors, such as heat-treatment conditions, concentration of oxygen and doping level in initial crystals, on center formation was studied. An asymmetric diffuse-ray scattering was observed near the surface of a crystal irradiated by thermal neutrons and annealed in a chlorine-containing atmosphere. This scattering is related to the formation of structural defects of the vacancy type. In the same region of the crystal, the concentration of the E7 center was one order of magnitude higher than that of other deep-level centers. Comparison of the-ray diffraction and deeplevel transient spectroscopy (DLTS) data suggests that the formation of the center occurs under the conditions of Si supersaturation with vacancies.     

3-acyl-1,2,3,4-tetrahydropyridine-2,4-diones: Synthesis and chemical properties

N-Substituted 6-methyl-1,2,3,4-tetrahydropyridine-2,4-diones reacted with aliphatic carboxylic acid chlorides in the presence of pyridine or triethylamine to give the corresponding 4-O-acyl derivatives which underwent O,C-migration of the acyl group by the action of 2 equiv of triethylamine and a catalytic amount of 2-hydroxy-2-methylpropanenitrile. Reactions of 3-acyl-6-methyl-1,2,3,4-tetrahydropyridine-2,4-diones thus formed with aliphatic and aromatic amines gave the corresponding enamino derivatives at the side acyl group. Enamino derivatives at the C⁴ =O group were obtained by transformation of 3-acyl-1,2,3,4-tetrahydropyridine-2,4-diones into 3-acyl-4-methoxy-6-methyl-1,2-dihydropyridin-2-ones via alkylation with dimethyl sulfate and subsequent treatment with amines.     

Synthesis of 17a-ethoximino derivatives of 8-aza-d-homogona-12,17a-diones by annelation of 3,4-dihydroisoquinolines with 2-acetyl-3-ethoximino-5,5-dimethylcyclohexanone

[2+4] Cyclocondensation of 3,4-dihydroisoquinolines with 2-acetyl-5,5-dimethyl-3-ethoximinocyclo-hexanone has been used to synthesize the previously unavailable 17a-ethoximino derivatives of 8-aza-D-homogona-12,17a-diones.Institute of Bioorganic Chemistry, Belorussian Academy of Sciences, Minsk 220141. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 232–235, February, 1999.     

Mechanism of reactions of acyl isocyanates with azomethines

Conclusions A study of the isomerization of the adducts, and the isolation of the free bipolar ion from the reaction of trichloroacetyl isocyanate with p-dimethylaminobenzalaniline, disclosed that the reaction of acyl isocyanates with azomethines belongs to the type of 1,4-dipolar cycloaddition.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 953–954, April, 1977.     

4-Acyl-2H-thiopyran-3,5(4H,6H)-diones: Synthesis,Oxidation, and Reaction with Amines

Acylation of 2H-thiopyran-3,5(4H,6H)-dione and 2-methyl-2H-thiopyran-3,5(4H,6H)-dione with acetyl chloride or propionyl chloride afforded the corresponding 4-acyl-2H-thiopyran-3,5(4H,6H)-diones. Oxidation of 4-acetyl-2H-thiopyran-3,5(4H,6H)-dione with m-chloroperoxybenzoic acid gave 4-acetyl-2H-thiopyran-3,5(4H,6H)-dione 1-oxide. 4-Acyl-2H-thiopyran-3,5(4H,6H)-diones and 4-acetyl-2H-thiopyran-3,5(4H,6H)-dione 1-oxide reacted with pyrrolidine, allylamine, and p-anisidine, resulting in formation of the corresponding 4-aminomethylene derivatives.     

Potentiometric biosensing of proteins with ultrasensitive ion-selective microelectrodes and nanoparticle labels

We report here for the first time on the use of potentiometry for ultrasensitive nanoparticle-based detection of protein interactions. A silver ion-selective microelectrode is used to detect silver ions oxidatively released from silver enlarged gold nanoparticle labels in a sandwich immunoassay. Since potentiometry is expected to largely maintain its analytical characteristics upon reducing the sample volume, it is anticipated that this approach may form the basis for bioassays with attractive detection limits.