Bromination of 3-acyl-2-aminoindoles

Unlike 3-acylindoles, 3-acyl-2-aminoindoles display high selectivity on being electrophilically attacked in the benzene ring, and are substituted at the 6-position. At the same time, an unco-subsitution of the acyl group takes place (to the greatest extent — the formyl group). Direct bromination of 3-acyl- and 3-cyano-2-aminoindoles provides the 6-bromo- and 6,4-dibromo-2-aminoindoles and their derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 486–490, April, 1990.     

A spin-dependent unitary group approach to many-electron systems

In this article we derive a segment-level formula for the matrix elements of the U(2n) generators in a basis symmetry adapted to the subgroup U(n) × U(2) (i.e., spin-orbit basis), for the representations appropriate to many-electron systems. This enables the direct evaluation of the matrix elements of spin-dependent Hamiltonians.     

Halogenation of isoflavones using thionyl and sulphuryl chlorides

The reactions of thionyl and sulphuryl chlorides on isoflavones have been found to give a number of new chloroisoflavones and isoflavanones, whose structures have been elucidated on the basis of their spectral analytical data.     

On the behavior of α-brominated dimethyl o-benzenediacetate toward nitrogen nucleophiles. Part II. Reaction of dimethyl α-bromo-o-benzenediacetate with hydrazines

Dimethyl α-bromo-o-benzenediacetate ( 1 ) condensed with hydrazine and acetylhydrazine to give respectively 1-carbomethoxy-2-amino-1,4-dihydro-3-(2H)isoquinolinone (2) and its N-acetyl derivative ( 9 ). Replacement of the bromine atom of 1 with the N-1-methylhydrazino ( 3 ) and the N-1-phenylhydrazino ( 5 ) groups occurred by allowing 1 to react respectively with methylhydrazine and phenylhydrazine. In the latter case alkylation by 1 at the N-2 also occurred which led to the formation of the 2-phenylaminoisoquinolinone ( 8 ). Derivatives 3 and 5 smoothly cyclized to the 1-earbomethoxy-5(H)-1,2,3,4-tetrahydro-2,3-benzodiazepin-4-ones 4 and 6 . A series of derivatives of 2 were also pharmacologically tested as antiinflammatory and CNS depressant agents.     

Pyrimidines

The condensation of -substituted acetophenones with benzylidenebisurea in an acid medium has given 5-R-2-oxo-4,6-diphenyl-1,2,3,4-tetrahydropyrimidones. The analogous condensation of propiophenone forms 5-methyl-2-hydroxy-4,6-diphenylpyrimidine. The tetrahydro derivatives obtained are readily dehydrogenated to 5-R-2-hydroxy-4,6-diphenylpyrimidines.For part XX, see [1].     

Phase diagram and X-ray diffraction analysis of the acrylic acid–acrylamide system

The phase diagram of the acrylic acid–acrylamide system as determined by DTA and the supporting x-ray diffraction data are presented. This diagram shows that the system forms a 1 : 1 addition compound which decomposes above 0°C. There is also one eutectic point at a 67 mole-% acrylic acid composition.     

Über die Konstitution eines Nebenalkaloides aus Adhatoda vasica Nees

Zusammenfassung Das in der vorangehenden Mitt. vonE. Späth undF. Gandini-Kesztler beschriebene Nebenalkaloid wird auf synthetischem Wege mit dem 6-Hydroxy-peganin identifiziert. Die phenolische OH-Gruppe steht also, bezogen auf Formel III, nicht an der Stelle, welche dem CH₃O des Harmins entspricht.     

Accurate local spin-polarized exchange potential: Reconciliation of generalized Slater and Kohn–Sham methods

Using simple physical arguments, a local spin-polarized exchange potential, V_xσ, is constructed from the single-particle Hartree–Fock (HF ) potentials (generalized Slater method) that reduces to the usual Kohn–Sham (KS ) result in the uniform gas limit. Numerical results for 10 closed subshell atoms demonstrate that the total energy calculated employing this V_xσ is closer to the exact KS results than those of other standard exchange approximations with electron densities and highest occupied orbital eigenvalues that closely approximate the HF results.     

Skeletal reactions of perfluoromethylethyl- and perfluorodiethylbenzocyclobutenes with 1,1- and 1,2-alkyl groups in SbF5

Taking perfluoro-1,1-dialkylbenzocyclobutenes as examples, it has been shown to be possible to enlarge the four-membered ring in polyfluorobenzocyclobutenes to five-membered in the presence of SbF₅, by cleavage of the four-membered ring followed by cyclization of the resulting polyfluorostyrene to the polyfluoroindane, which then undergoes further reactions. Perfluoro-1-methyl-1-ethylbenzocyclobutene isomerizes at 50°C in the presence of SbF₅ to perfluoro-,-o -trimethylstyrene, which is reversibly converted at 130°C into perfluoro-1,2-dimethylindane. Perfluoro-l,l-diethylbenzocyclobutene isomerizes at 130°C in the presence of SbF₅ to give perfluoro- -ethyl-,o -dimethylstyrene, which at 170°C gives perfluoro-2-methyl-3-ethylindene- and perfluoro-2-methyl-3-ethyl-4,5,6,7-tetrahydroindene. The last two compounds, together with perfluoro-o-dipropylbenzene, are obtained from per fluoro-1,2-diethylbenzocyclobutene-with SbF₅ at 170°C. From perfluoro-1-methyl-2-ethylbenzocyclobutene with SbF₅ at 95°C there is obtained perfluoro-1-ethylindane, while at 130°C, in addition to the latter compound, there are obtained perfluorinated 1,1-dimethylindane, 1,2-dimethylindane, ,,o-trimethylstyrene, 2,3-dimethylindene, and 2,3-dimethyl-4,5,6,7-tetrahydroindene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1114–1120, May, 1990.     

Electrochemical reductive breakdown of solid-phase chlorinated rubber in aprotic and aqueous media

A study has been made of the electrochemical reductive breakdown (ECRB) of solid-phase chlorinated butyl rubber (CBR). It has been established that CBR does not accept electrons under conditions of fast sweep of electrode potential; however, with prolonged cathodic polarization of the substrate at the polymer/cathode/solution three-phase boundary, it undergoes reduction and subsequent chemical conversion, including intermolecular cross-linking and breakdown of the macromolecules. The rate of ECRB of the CBR depends on the potential and materials of the cathode, and also on the nature of the solvent. In a aprotic medium, the process of CBR breakdown leads to the formation of long polyconjugated structures that color its surface black in the vicinity of the three-phase boundary. In an aqueous medium, no such color is observed, but the products of ECRB are found to contain conjugated double bonds with a shorter conjugation chain than in the case of the aprotic medium. It has been established that he starting reaction in ECRB of CBR is reduction of the C-Cl bond and subsequent elimination of Cl^–.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 6, pp. 710–715, November–December, 1989.