The Reaction of Cyclic Nitroenamines with Isocyanates. Synthesis of 1,6-Polymethylene-6-nitromethyl-1,3,5-triazine-2,4-dione Derivatives

The reactions of cyclic nitroenamines with isocyanates were investigated. It was found that two different products could be obtained: in inert media -carbamoyl products were observed and when a strong base was used 1,6-polymethylene-6-nitromethyl-1,3,5-triazine-2,4-dione derivatives were isolated.     

Molecular and crystalline structure of λ3-2,4,6-tri-tert-butylphenyldibromomethylenephosphine

Institute of Organic Chemistry, Ukrainian Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 2, pp. 174–177, March–April, 1992.     

Domains in C n+1 with noncompact automorphism group

We consider certain pseudoconvex domains in C ⁿ⁺¹ and show that if the automorphism group is noncompact, then the domain is equivalent to for some integerm ≥ 1. Communicated by Steven Krantz     

Quantum chemical modeling of the photode-composition of the water dimer in chlorophyll complexes of magnesium and manganese

On the basis of quantum-chemical calculations in the MPNDO/3 approximation, a reaction has been proposed for the photodecomposition of water in complexes M·Chl_a...(H₂O)₂M·Chl_a+O₂+4H⁺+4e^– (M=Mg, Mn), which suggests an interpretation of the primary event of photosynthesis. Calculations of the photosynthetic evolution of oxygen according to the Joliot-Kok model in complexes M·Chl_a...(H₂O)₂ are in good agreement with the experimental data of the thermoluninescence of chlorophyll photosystem II.Kiev Polytechnic Institute. Translated from Zhurnal Strukturnoi Khimii, Vol. 34, No. 2, pp. 33–38, March–April, 1993.     

Motion of protons in the central opening of porphyrins

The distribution of the electrostatic potential of the molecule of porphine (P) and the anions formed by the successive elimination of one and two central protons from it has been studied by the SCF-MO-LCAO method in the all-valence-electron CNDO/2 approximation. The electrostatic potential of the potential of the (P-2HO^2– dianion is characterized by the presence of four minima located at a distance of about 1 Å from the nitrogen atoms. The potential in them is equal to –991 kJ/mole. The value of the potential at the center of the opening is –978 kJ/mole. The distribution of the electrostatic potential of the (P-H)^– anion with a fixed position of the proton near one of the nitrogen atoms is characterized by the presence of a deep valley situated at the oppositely lying nitrogen atom perpendicularly to the N-H bond. The potential of the molecule of P in the plane of the ring does not have negative values, attesting to the energetic unfavorability of the planar conformations of the (P+H)⁺ cation.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 2, pp. 216–220, March–April, 1986.     

Characteristics of polyether urethanes with mixed soft segments,prepared by two- and three-step procedures

A three-step procedure for preparing polyurethanes with mixed polyether segments was suggested. It involves preparation of the “inverse” prepolymer by the reaction of one of oligodiisocyanates with 1,4-butanediol taken in a double excess, followed by the reaction with the other oligodiisocyanate. Polyurethanes with alternating poly(tetramethylene oxide) and poly(propylene oxide) soft segments were prepared by this procedure. Such materials surpass polyurethanes prepared from a mixture of oligodiisocyanates in the strength and softening point of the hard phase. In contrast to poly(tetramethylene oxide) urethane, elastomers with mixed polyether segments do not crystallize.     

C-Phosphorylation of Formamidines

C-Phosphorylation of formamidines by trivalent phosphorus halides was researched. Direction of the phosphorylation depends on nature of substituents at the amidine nitrogens. C-Phosphorylated products was shown to be of valuable possibilities to construct phosphoruscontaining heterocycles