Dipole moments and molecular conformations of acetylpyrimidines

By comparing experimentally determined dipole moments with those derived from vector-addition and semiempirical computation using MNDO and AM 1 approximations the conformations of 4- and 5-acetylpyrimidines were found to be close to planar, while that of 2-acetylpyrimidine exhibited a torsion angle of 90°.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1387–1390, October, 1992.     

Synthesis of isomeric aminophenylbipyrimidines and study of the liquid crystalline properties of anils structurally related to aminophenylpyrimidines

5-Amino-2,5bipyrimidines and bis-(5-aminopyrimidinyl-2)-p-phenylenes have been synthesized as well as isomeric bis-(p-aminophenyl)pyrimidines. From these, substituted benzylidenamino derivatives have been prepared and their liquid crystalline properties studied.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 509–513, April, 1993.     

Synthesis and Biological Activity of Cyanoethyl Derivatives of Fusidic Acid

3,11-Dihydroxy and 3,11-dioxo triterpenoids of the fusidane series reacted with acrylonitrile in 1,4-dioxane in the presence of alkali and phase-transfer catalyst to give mono- and bis(2-cyanoethoxy) and 2-cyanoethyl derivatives. The reaction with 3,11-dioxo analog afforded 2,2-disubstituted derivative as a result of addition of two cyanoethyl groups to the α-position with respect to the C³=O carbonyl group. The isolated compounds were screened for antibacterial and antifungal activities.

     

Synthesis of schiff bases of 2-substituted 5-aminopyrimidines and their mesomorphic properties

Schiff bases of 2-substituted 5-aminopyrimidines were synthesized, and their liquid-crystal and dielectric properties were investigated. It is shown that narrow ranges of the existence of meso phases and a greater (as compared with benzyl-ideneanilines) tendency for the development of a smectic state are characteristic for 2-alkoxy-, 2-alkyl-, and 2-cyano-5-arylideneaminopyrimides. The introduction of an aryl substituent into the 2 position of the pyrimidine ring gives rise to a pronounced increase in the thermostability of the meso phase and significantly increases the range of its existence. The use of groups with higher dipole moments as terminal groups leads to the production of compounds with high positive dielectric anisotropies.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1545–1552, November, 1982.     

Acylation and oxidation of 4-chloro-6-hydroxyaminopyrimidines. Synthesis of 4-chloro-6-nitro(nitroso)pyrimidines

Treatment of 2-R-4,6-dichloropyrimidines with hydroxylamine gives 2-R-4-chloro-6-hydroxyaminopyrimidines, which are converted to mono- and diacyl derivatives upon acylation. Oxidation of 4-chloro-6-hydroxyaminopyrimidines with manganese dioxide or ozone gives the first reported synthesis of 4-chlorine-containing 6-nitroso- or 6-nitropyrimidines, respectively.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1088–1093, August, 1989.     

Pyrimidines. 70. Relative reactivities of the chlorine atoms of 2,2′,4-trichloro-4′,5-dipyrimidinyl in its reaction with piperidine

2,2,4-Trichloro-6-phenyl-4,5-dipyrimidinyl, for which nucleophilic substitution with piperdine under various conditions was studied, was obtained from 2,2,4-trioxo-6-phenyl-1, 1,2,2,3,4-hexahydro-4,5-dipyrimidinyl. It is shown that there is an appreciable difference in the rates of substitution of the first, second, and third chlorine atoms, and this made it possible to obtain reaction products that contain one, two, and three piperidino groups. The chlorine atom in the 4 position is replaced initially, after which the chlorine atom in the 2 position undergoes substitution. The structures of the compounds were proved by chemical transformations and analysis of the PMR spectra.See [1] for communication 69.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 821–826, June, 1979.     

Synthesis of 2- and 4-Nitropyrimidines and 2-Nitro-sym-triazines by ozonization of hydroxyamino and nitroso derivatives

The action of ozone on aryl(methyl)-substituted 2- and 4-hydroxyamino- or -nitrosopyrimidines in chloroform gave 2- and 4-nitropyrimidines. The unambiguous character of the process depends on the molar ratio of the substrate and ozone; the side formation of azoxy-, chloro-, and hydroxypyrimidines is possible. 2-Nitro-sym-triazines were obtained by ozonization of substituted 2-hydroxyamino-sym-triazines.See [1, 2] for our preliminary communications.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 657–661, May, 1990.     

Determination of the parameters of the two-well potentials of slightly asymmetric hydrogen bonds in the enols of B-diketones by the NMR method

Institute of Bioorganic Chemistry, Academy of Sciences of the Belorussian SSR. M. V. Lomonosov Moscow State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 4, pp. 46–50, July–August, 1991.     

Pyrimidines

Some hydrogenation products of 2-hydroxy-4-phenylbenzo [h]quinazoline are acetylated with acetic anhydride. Mono and diacetyl derivatives are obtained, depending on the extent of hydrogenation of the quinazoline ring. From spectroscopic data structures are put forward for these compounds. Formation of a diacetyl derivative from 2-hydroxy-4-phenyl-3, 4, 5, 6-tetrahydrobenzo [h]quinazoline offers support for a previously advanced view regarding its structure.For Part III see [1].